1 00:00:00,000 --> 00:00:10,000 The fuel is burning down to my bones 2 00:00:10,000 --> 00:00:16,000 But I see the truth now 3 00:00:16,000 --> 00:00:21,000 I'll never be more alone 4 00:00:21,000 --> 00:00:26,000 I run through the trees as fast as I can 5 00:00:26,000 --> 00:00:31,000 I fall to my knees and I find a place to land 6 00:00:31,000 --> 00:00:35,000 Whisper in the moonlight, stopping the life we 7 00:00:35,000 --> 00:01:04,000 freeze, see into the shadows, taking over me 8 00:01:05,000 --> 00:01:10,000 I'm sorry for the long absence from the show 9 00:01:10,000 --> 00:01:15,000 Life has been a little crazy for all of us 10 00:01:15,000 --> 00:01:20,000 We appreciate your patience while you waited for our next episode to come out 11 00:01:20,000 --> 00:01:25,000 On an exciting note, me, Jenna, speaking to you now, I got a job 12 00:01:25,000 --> 00:01:30,000 I'm now working for the court system here in Ontario as an exhibit clerk 13 00:01:30,000 --> 00:01:34,000 Full disclaimer though, I have to go through the nitty gritty of it 14 00:01:34,000 --> 00:01:37,000 This is not the presentation of the Ontario or Superior Court of Justice or the 15 00:01:37,000 --> 00:01:41,000 Ministry of the Attorney General 16 00:01:41,000 --> 00:01:44,000 So anything that I say is just purely my own opinion 17 00:01:44,000 --> 00:01:48,000 And how I feel about stuff and it has nothing to do with our Ontario court system 18 00:01:48,000 --> 00:01:56,000 That being said, I'm going to throw it over to Ashley to introduce this week and our new guest 19 00:01:56,000 --> 00:02:01,000 Well hello and welcome everybody 20 00:02:01,000 --> 00:02:08,760 Tiffany and she'll be discussing isotopes, which is something that one of you all wanted us to 21 00:02:08,760 --> 00:02:17,560 discuss today. We wanted to talk about isotopes today because this is a new and growing area 22 00:02:17,560 --> 00:02:24,440 within the field of anthropology, particularly in the area of identifying people and locations 23 00:02:24,440 --> 00:02:31,720 from where they come from. And we have today Dr. Tiffany Prakasha. 24 00:02:32,600 --> 00:02:33,240 Brachia. 25 00:02:33,880 --> 00:02:36,200 Brachia. I'm not like the bread. 26 00:02:39,080 --> 00:02:46,280 I was a professor at Vanderbilt University. So if you want, go ahead and introduce yourselves. And 27 00:02:46,280 --> 00:02:51,080 what got you interested in isotopes as an area of research? 28 00:02:51,080 --> 00:02:59,080 Well, again, I'm Dr. Tiffany Frachia and I'm an associate professor of the practice of anthropology 29 00:02:59,080 --> 00:03:05,000 at Vanderbilt University. In addition to that, you hear that professor of the practice piece. What 30 00:03:05,000 --> 00:03:13,640 that means is I'm also in my field of study actively practicing. So here in the middle Tennessee area, 31 00:03:13,640 --> 00:03:20,040 I'm responsible for forensic anthropology casework across numerous counties. So I'm 32 00:03:20,040 --> 00:03:27,640 actually completed a forensic case today. And so I do casework, I'm teaching courses, 33 00:03:27,640 --> 00:03:33,800 and I'm actively engaged in research. And so I really like the question of how did I find my way 34 00:03:33,800 --> 00:03:45,320 to isotope analysis? Because I did not start out as a young child or a teenager, even an undergraduate 35 00:03:45,320 --> 00:03:51,880 student thinking, wow, I really want to do isotope analysis as a research topic, or this is something 36 00:03:51,880 --> 00:03:59,400 I want to learn more about. It was not until I was working on a master's degree in biology 37 00:03:59,400 --> 00:04:06,280 with still a very strong focus in anthropology that I first heard about isotope analysis 38 00:04:06,280 --> 00:04:14,280 as a tool for forensic anthropologists. I heard about it at a workshop for forensic anthropologists 39 00:04:14,280 --> 00:04:20,680 and they were talking about what happens when the biological profile that we create as forensic 40 00:04:20,680 --> 00:04:27,560 anthropologists doesn't lead to any perspective identifications. And here in the United States, 41 00:04:27,560 --> 00:04:35,080 what happens is that case goes cold very quickly. And isotope analysis can tell us a little bit more 42 00:04:35,080 --> 00:04:41,400 about someone. It's important to note that this is not an outright identification tool. So we 43 00:04:41,400 --> 00:04:47,000 don't get the same one-to-one comparison like we do for DNA where it tells you exactly who this person 44 00:04:47,000 --> 00:04:53,560 is. Isotope analysis gives us sort of big picture categories. And the whole premise that makes it 45 00:04:53,560 --> 00:04:59,400 work is that you are what you eat and you're also where you eat. So we can use chemical signatures 46 00:04:59,400 --> 00:05:04,280 from our bones and from our teeth and from our hair and other tissues to tell us more about 47 00:05:04,280 --> 00:05:09,960 someone's dietary history and their geographic origins. So when I first heard about this and I 48 00:05:09,960 --> 00:05:15,880 heard new tool in forensic anthropology, all of these bells and whistles started going off for me 49 00:05:15,880 --> 00:05:22,600 in terms of that could be something I could learn more about. And I think for a lot of graduate 50 00:05:22,600 --> 00:05:30,040 students, that's the struggle is being very intimidated because you love this field. So for 51 00:05:30,040 --> 00:05:35,240 us, we love anthropology. We love forensic anthropology and we want to contribute to our 52 00:05:35,240 --> 00:05:42,040 field with research, but it feels like everything's already been done. And so for me to hear that there 53 00:05:42,040 --> 00:05:50,840 was something new that was so obviously exciting for people that really drew me in and I wanted to 54 00:05:50,840 --> 00:05:56,600 know more. I did mention I did a master's degree in biology. So that hard science piece of this is 55 00:05:56,600 --> 00:06:04,200 also really appealing to me. And so it became a way that I could merge anthropological theory 56 00:06:04,200 --> 00:06:10,680 with sort of a hard science. And that was really what prompted me to look into this further. 57 00:06:11,240 --> 00:06:18,600 I was very fortunate to work with Dr. Donnie Stedman at the University of Tennessee in Knoxville 58 00:06:18,600 --> 00:06:25,000 as my dissertation advisor. And I had talked to Dr. Stedman early on in my application process 59 00:06:25,000 --> 00:06:30,840 about wanting to pursue isotope analysis as a research topic for my dissertation. And she was 60 00:06:30,840 --> 00:06:36,760 very supportive from the beginning. It's important to note that isotope analysis is a destructive 61 00:06:36,760 --> 00:06:43,960 analysis. And so when you're looking for a research topic, you have to think about the materials that 62 00:06:43,960 --> 00:06:49,240 are available to you. And so since our skeletal collections are such a precious and finite 63 00:06:49,240 --> 00:06:55,240 resource, and we also want to treat them with the utmost respect, we have to really consider 64 00:06:55,240 --> 00:07:00,280 whether the data that we're getting and what we can learn from that is justified in the questions 65 00:07:00,280 --> 00:07:06,680 that we're asking and that destructive analysis piece of this. So that was sort of how I wandered 66 00:07:06,680 --> 00:07:13,000 into this and a few of the pieces about how I got there. I did do my dissertation research 67 00:07:13,560 --> 00:07:20,520 at the UT Knoxville Forensic Anthropology Center Anthropology Research Facility, also very commonly 68 00:07:20,520 --> 00:07:27,240 known as the Body Farm. So that's also something that's available for us to talk about today if 69 00:07:27,240 --> 00:07:36,520 you have questions about that. But in general, this idea of figuring out who someone is using 70 00:07:36,520 --> 00:07:44,520 an extra clue or extra information using diet history and also using geographic travel history 71 00:07:44,520 --> 00:07:58,680 was what sort of got me there. Interesting. I do have one question. What are isotopes and isotopic 72 00:07:58,680 --> 00:08:06,680 analysis? I mean, it's... Yeah, what are they? For the non-chemistry people, maybe. People who 73 00:08:06,680 --> 00:08:13,320 have taken those hard sciences. Well, so we talked about what was exciting about this topic for me, 74 00:08:13,320 --> 00:08:19,080 but we should also mention what was intimidating about this topic for me. A lot of people don't 75 00:08:19,080 --> 00:08:25,480 enjoy chemistry. I was very excited about the hard science piece of this, but I was very intimidated 76 00:08:25,480 --> 00:08:31,400 by the chemistry piece of this. And so it's important to know that using isotope analysis, 77 00:08:32,440 --> 00:08:37,400 which is again, using those sort of chemical signatures that we can get from our bones and 78 00:08:37,400 --> 00:08:46,440 teeth and other human tissues to tell us more about a person's lived experiences. Thinking about that 79 00:08:47,080 --> 00:08:51,240 from an anthropological perspective is very different than thinking about it from the 80 00:08:51,240 --> 00:08:57,640 chemistry laboratory perspective. And so not only did I receive anthropological training, but I had 81 00:08:57,640 --> 00:09:06,200 to seek out opportunities to learn the chemistry piece of this. And so I attended a two-week 82 00:09:06,200 --> 00:09:14,440 intensive course, which was at the time held at the University of Utah called ISOCamp. And so my 83 00:09:14,440 --> 00:09:21,880 friends to this day refer to this as that time you went to nerd camp. But it was two weeks intensive 84 00:09:21,880 --> 00:09:30,760 learning about all of the biology and chemistry that goes into this. So the question of what is 85 00:09:30,760 --> 00:09:37,400 an isotope requires us to go back to chemistry. And so what I always ask people to do is picture 86 00:09:37,400 --> 00:09:44,280 the periodic table and think about all of those letters and numbers and those little squares on 87 00:09:44,280 --> 00:09:51,960 the periodic table. If we scrolled across the periodic table and we found the element carbon, 88 00:09:52,680 --> 00:09:58,280 we would find the number six with the element carbon. And what that number six tells us is 89 00:09:58,280 --> 00:10:04,280 that there are six protons in the nucleus of a carbon element. So having those six protons 90 00:10:04,280 --> 00:10:09,640 means that it's carbon. It's going to act like carbon no matter what. But there are different 91 00:10:09,640 --> 00:10:19,080 versions of carbon. And so there's different versions come to us by the number of neutrons 92 00:10:19,080 --> 00:10:27,480 that are present. So what we're looking for is adding those together and we get carbon 12 when 93 00:10:27,480 --> 00:10:33,800 there are six of those and we get carbon 13 when there are seven. And we also get the radiogenic 94 00:10:33,800 --> 00:10:38,760 or the radioactive version of carbon, which is carbon 14, which a lot of people have heard of 95 00:10:39,480 --> 00:10:48,520 for use in radiocarbon dating. So telling us how old the really old stuff is. So an isotope, 96 00:10:48,520 --> 00:10:57,560 very simply put, is two versions of the same element. So it's got just a slight difference 97 00:10:57,560 --> 00:11:01,960 of the contents of its nucleus. It's always going to have six protons because it's carbon, 98 00:11:02,840 --> 00:11:09,480 but there is slight variety in those other components that make up that atom. 99 00:11:11,160 --> 00:11:16,280 So pretty easy, right? And when we do isotope analysis, what we're actually doing is measuring 100 00:11:16,280 --> 00:11:23,480 the ratio of those two different versions. So we talk a lot about stable isotope analysis. 101 00:11:23,480 --> 00:11:29,080 And what this means is we're looking at the stable form. So they stay consistent over time. So they 102 00:11:29,080 --> 00:11:37,160 don't break down the same way radiogenic or radioactive elements do. So that radiocarbon, 103 00:11:37,160 --> 00:11:43,800 that carbon 13 or carbon 14 breaks down, has a decay that's very different from these more stable 104 00:11:43,800 --> 00:11:49,640 versions. So that's where we get that stable isotope analysis piece of this. So when we're 105 00:11:49,640 --> 00:11:57,560 making these measurements, we're using a mass spectrometer and we are combusting samples and 106 00:11:57,560 --> 00:12:01,880 we're measuring those different forms of the elements we're interested in and then we're 107 00:12:01,880 --> 00:12:10,440 reporting those as a ratio. So a few of the elements that I'm interested in isotopic analysis of 108 00:12:10,440 --> 00:12:17,160 are carbon and nitrogen, oxygen and strontium. So these are the ones that I use in anthropology 109 00:12:17,160 --> 00:12:25,640 pretty frequently. I say, I really like how you said, you are what you eat, you are where you eat, 110 00:12:25,640 --> 00:12:37,400 those types of things. I know in my personal work with isotopes, my boss always says, it's like 111 00:12:37,400 --> 00:12:42,600 eating vanilla ice cream, but do you like French vanilla or do you like regular vanilla or do you 112 00:12:42,600 --> 00:12:47,480 like, like there's various kinds and sometimes you might put a scoop of French vanilla and a 113 00:12:47,480 --> 00:12:51,960 scoop of regular vanilla in your bowl and you have all of that inside of you. And so I really 114 00:12:51,960 --> 00:13:01,080 appreciate the like, you are what you eat situation. I say, as far as, so for a lot of our listeners, 115 00:13:01,080 --> 00:13:07,880 you know, they're anthropology students or just lay people who probably like myself didn't really 116 00:13:07,880 --> 00:13:15,480 enjoy my chemistry classes in school if I took them. But when you're thinking about carbon and 117 00:13:15,480 --> 00:13:22,680 the variations on carbon, what do you, I guess for those, for our audience, what does that carbon 118 00:13:22,680 --> 00:13:33,400 and nitrogen reflect dietarily? Is it a certain type of food or what? So, yes, so we mentioned 119 00:13:33,400 --> 00:13:37,560 that there are a couple different things we can get from isotopes, one of those being sort of a 120 00:13:37,560 --> 00:13:44,440 picture of someone's diet. So when we're looking at carbon isotopes, we're actually looking at what 121 00:13:44,440 --> 00:13:53,560 kind of plants people are eating. So isotope analysis has this very rich history in anthropology 122 00:13:53,560 --> 00:14:01,160 and it actually started in archaeology. So looking at the remains of people from the past. And so the 123 00:14:01,160 --> 00:14:07,480 questions that we wanted to ask and answer were, you know, we think we're seeing certain cultural 124 00:14:07,480 --> 00:14:14,600 practices reflected in the artifacts that are found with these people, but does that truly reflect 125 00:14:15,320 --> 00:14:23,160 what's happening? So for example, if we're finding evidence of agriculture and we're 126 00:14:23,160 --> 00:14:29,000 presuming that people were engaging in maize agriculture, so they were going, growing corn, 127 00:14:30,200 --> 00:14:34,680 were they actually eating the corn or were they doing something else with the corn? 128 00:14:34,680 --> 00:14:41,960 And so when we drill down quite literally to these chemical analyses of human remains, 129 00:14:41,960 --> 00:14:48,920 what we would be looking at are those embodiments of cultural practices. So we're looking at 130 00:14:50,360 --> 00:14:58,120 what kind of foods were they consuming? And we differentiate plants by these different categories. 131 00:14:58,120 --> 00:15:03,560 And so primarily we're interested in what we call C3 plants and C4 plants. There's something else 132 00:15:03,560 --> 00:15:08,680 called CAM plants that can factor into this, but that gets really complicated. So for sake of this 133 00:15:08,680 --> 00:15:15,080 discussion, we'll focus on C3 versus C4. And when we're differentiating those, we can talk about the 134 00:15:15,080 --> 00:15:25,000 C3 plants as being things that we think of as a more wild grain based diet. So things like 135 00:15:25,000 --> 00:15:31,400 wild grasses, things that we would think would occur naturally in the environment, as opposed 136 00:15:31,400 --> 00:15:36,760 to C4 plants, which are things that we associate more with agriculture and cultivation. So things 137 00:15:36,760 --> 00:15:46,760 like corn, sugar cane, those are things that we see marking that difference in behavior 138 00:15:47,640 --> 00:15:53,080 archaeologically. So that's really where isotopes as a tool kind of got its start with anthropology. 139 00:15:53,640 --> 00:15:59,480 And we were really interested in what people were eating and what kinds of plants they were eating. 140 00:15:59,480 --> 00:16:04,920 When we measure nitrogen, what we're actually asking is where are you on the food chain? 141 00:16:04,920 --> 00:16:12,200 So we're looking at whether someone has a more plant-based diet or has more meat in their diet. 142 00:16:12,200 --> 00:16:17,320 And what we're essentially measuring is the protein content from meat-based products. 143 00:16:18,360 --> 00:16:24,840 So when you see someone higher up on the nitrogen values, you can assume that they are eating 144 00:16:24,840 --> 00:16:35,880 more meat in their diet. I say, is that also true for... I know a lot of the isotope stuff that I 145 00:16:35,880 --> 00:16:43,640 do for my job is trying to determine, are you a US citizen or eating a typical US diet versus 146 00:16:43,640 --> 00:16:50,920 eating a non-typical US diet? And a lot of times we look at carbons and nitrogens to try to get at 147 00:16:50,920 --> 00:16:58,840 that. And one thing that's always talked about at work is United States, you eat a lot of meat, 148 00:16:58,840 --> 00:17:02,520 like you might not necessarily eat a lot of corn, but the meat you're eating is eating a lot of corn. 149 00:17:03,080 --> 00:17:10,440 And that's not necessarily true worldwide. So like kind of thinking about cultural differences 150 00:17:10,440 --> 00:17:18,440 between what different areas of the world might be eating. Can you look at that and try to get at 151 00:17:18,440 --> 00:17:25,800 migration or movement of people, both, I guess, archeologically and anthropologically? 152 00:17:26,760 --> 00:17:33,640 Absolutely. I think that's a fantastic question. And that's where I see the most active research 153 00:17:33,640 --> 00:17:39,480 right now and a lot of aspects of isotope analysis is an attempt to address these questions about 154 00:17:40,520 --> 00:17:46,600 deceased migrants who have died in a different place than they lived. So 155 00:17:46,600 --> 00:17:53,720 when we think about geographic history, we're thinking about where someone's been over the 156 00:17:53,720 --> 00:18:01,560 course of their lives. And so when we ask those questions, we can use diet. We can also use things 157 00:18:01,560 --> 00:18:09,240 like the drinking water consumption, and we can measure that and make comparisons to drinking water 158 00:18:09,240 --> 00:18:15,560 across the world. And so we use oxygen isotopes for that. And we can also use strontium as a 159 00:18:15,560 --> 00:18:21,960 geolocator. When you're thinking about diet and sort of making those differentiations between people, 160 00:18:21,960 --> 00:18:27,240 I think it's always useful to use what we call a multi isotope approach. And I think that 161 00:18:27,240 --> 00:18:32,360 in your question was sort of embedded that idea, right? So it's not just which plants are you 162 00:18:32,360 --> 00:18:39,160 eating, but it's which plants are you eating in terms of the way that you're eating. And so 163 00:18:39,160 --> 00:18:45,480 combination with how much protein you're getting in your diet. And then not just what are you eating, 164 00:18:45,480 --> 00:18:51,080 but what were your protein sources eating as well, right? Isotopes do sort of have that 165 00:18:51,080 --> 00:19:01,000 compounding effect. And so we are absolutely able to make these sort of distinctions if a 166 00:19:01,000 --> 00:19:07,800 population's behaviors are distinct enough, right? So that's always one of the questions that you 167 00:19:07,800 --> 00:19:16,360 have to start with in that preliminary research is can we find enough of a split between two 168 00:19:16,360 --> 00:19:24,280 different populations to say confidently, if a person has these values, they would most likely 169 00:19:24,280 --> 00:19:29,080 sort into this group. And if a person has these values, they would most likely sort into this 170 00:19:29,080 --> 00:19:34,680 group. And those two don't overlap or have minimal overlap. And that's ideal for sorting. 171 00:19:34,680 --> 00:19:40,760 So in the example you've given, you're thinking about people who've consumed a US-based diet, 172 00:19:40,760 --> 00:19:48,760 what's available to us very commercially in those resources that we associate with US agriculture 173 00:19:49,400 --> 00:19:58,120 versus something that may be a more grain-based diet. That's a product of plants growing differently 174 00:19:58,120 --> 00:20:03,960 in different parts of the world, right? Based on climate, based on soil types. So there are a lot 175 00:20:03,960 --> 00:20:10,600 of different pieces that we have to think about, but that sorting piece of this is super useful 176 00:20:10,600 --> 00:20:17,560 when you're asking the question, is this person local or not local? So does this person 177 00:20:18,120 --> 00:20:25,640 isotopically look like what we would expect from someone who originated in this area, 178 00:20:25,640 --> 00:20:29,800 or does this look like someone who may have been traveling from somewhere else? 179 00:20:29,800 --> 00:20:35,480 So in the United States, we know that we have a crisis at our southern border where we have 180 00:20:35,480 --> 00:20:42,280 people who are navigating hostile terrain and are succumbing to that in the desert, 181 00:20:43,080 --> 00:20:49,000 people who are dying far away from where their journey started. And so if we don't have any 182 00:20:49,000 --> 00:20:55,160 information about who that person is, a good starting point would be knowing where they came 183 00:20:55,160 --> 00:21:03,000 from so that we could start advertising that biological profile to find out if there are any 184 00:21:03,880 --> 00:21:11,240 missing persons in that particular area that might match the person that we've recovered and 185 00:21:11,240 --> 00:21:18,840 hopefully be able to repatriate those remains to their loved ones. This isn't a problem that's 186 00:21:18,840 --> 00:21:24,280 exclusive to the United States. Over the summer, I did some work in Tanzania where they're just 187 00:21:24,280 --> 00:21:33,000 starting the conversation. Tanzania has two main migrant routes that pass through a desert as well. 188 00:21:33,000 --> 00:21:38,760 So one to the north where people are coming from multiple countries trying to get to the 189 00:21:38,760 --> 00:21:44,280 Mediterranean, and then one that travels sort of to the south for people who are trying to get to 190 00:21:44,280 --> 00:21:53,000 South Africa. And people are coming from multiple countries, and it's very difficult to know where 191 00:21:53,000 --> 00:21:59,160 people originated again so that those bodies can be repatriated. So it's a problem within Tanzania 192 00:21:59,800 --> 00:22:05,880 regarding what do we do with these bodies? How do we honor these bodies according to their 193 00:22:05,880 --> 00:22:12,440 lived customs and traditions? But also the volume, which is something that we're experiencing at the 194 00:22:12,440 --> 00:22:19,560 southern US border as well. So being able to address these humanitarian needs of human 195 00:22:19,560 --> 00:22:25,880 identification, we need all the tools in our tool belt, and isotopes I think is a very useful one 196 00:22:25,880 --> 00:22:34,920 for that. This may be in the realm of theoretical more than practical at the moment, but can you 197 00:22:34,920 --> 00:22:44,040 also do this temporally as well as geographically? I mean, I'm thinking the changes we've had in US 198 00:22:44,040 --> 00:22:51,000 agriculture over the time, particularly with the development of grain, the development of corn, 199 00:22:51,000 --> 00:22:56,280 the development of soybean, development of our grasses to make them more stable, climate stable, 200 00:22:56,280 --> 00:23:02,600 et cetera. Would that have an impact on the isotopes? And could you theoretically at some 201 00:23:02,600 --> 00:23:10,280 point be able to say, this is someone from an older population because we see this type of isotopic 202 00:23:10,280 --> 00:23:15,080 signature and this one's from a newer population because we see a different isotopic signature? 203 00:23:15,800 --> 00:23:20,680 I think that's a great question. And I think that would be a fantastic avenue for somebody who's 204 00:23:20,680 --> 00:23:31,000 looking for a research project to sort of pursue. I think that it's got some good grounding 205 00:23:31,800 --> 00:23:35,640 theoretically because I'm just thinking of other examples of ways that we've 206 00:23:35,640 --> 00:23:40,840 sort of exploited chemical signatures from body tissues to tell us even more about a person. 207 00:23:41,480 --> 00:23:48,920 The example I'm thinking of that gives us a little bit of a timeline temporally is lead contents 208 00:23:50,360 --> 00:24:00,120 in people because we can measure lead content in populations where lead was part of the glaze 209 00:24:00,120 --> 00:24:07,800 lead was part of the glaze that was put on our dinnerware or lead in our pipes, 210 00:24:07,800 --> 00:24:14,600 but also leaded gasoline. And so we were breathing that. So that's something that has been used to 211 00:24:14,600 --> 00:24:19,480 sort of differentiate populations where leaded gasoline was used for longer periods of time 212 00:24:19,480 --> 00:24:26,120 than it was in the US. So there's definitely a sorting mechanism there. So I think that's a 213 00:24:26,120 --> 00:24:31,960 reasonable precedent to say that what you're proposing would potentially be viable for sure. 214 00:24:42,440 --> 00:24:43,480 Stephanie, you're muted. 215 00:24:43,480 --> 00:24:49,080 Sorry, I thought I was muted or I thought I was unmuted. But to kind of along the same lines of 216 00:24:49,080 --> 00:24:55,320 like research questions that might not have been answered yet because isotopes, 217 00:24:56,360 --> 00:25:02,600 while not being a new field overall, because there's been plenty of isotope research as far as 218 00:25:02,600 --> 00:25:09,560 soil content and other things like that and other fields of practice, but it's relatively new in 219 00:25:09,560 --> 00:25:16,840 anthropology. Do you have, I guess, any advice for someone who might be listening and thinking, 220 00:25:16,840 --> 00:25:25,000 might be listening and thinking, oh, I kind of like the idea of diet and migration patterns and 221 00:25:25,000 --> 00:25:33,720 getting to know that lived experience of the person, any avenues of how they should go about 222 00:25:33,720 --> 00:25:42,680 trying to decide maybe what schools are good for isotopic research or what are areas that the field 223 00:25:42,680 --> 00:25:48,760 has kind of been wanting people to do, but it just hasn't quite happened yet. Any advice for that type 224 00:25:48,760 --> 00:25:58,920 of stuff? Sure. Again, that was sort of the genesis for my dissertation project. My dissertation 225 00:25:58,920 --> 00:26:08,520 focused on looking at taphonomic processes and how they potentially impact isotopes. And I did that 226 00:26:08,520 --> 00:26:17,720 using hair. And so, you know, as anthropologists, we're very often thinking about bones and teeth 227 00:26:19,320 --> 00:26:26,920 because that's usually what we get. But those of us who practice in more arid conditions, 228 00:26:26,920 --> 00:26:34,120 so my colleagues who work in Peru, often recover thousand-year-old locks of hair. 229 00:26:34,120 --> 00:26:42,440 The primary decomposer of hair is fungus. So fungus really enjoys warm, wet areas. So if you have 230 00:26:42,440 --> 00:26:50,520 drier areas like crypts or tombs or even high-altitude arid climates, fungus doesn't 231 00:26:50,520 --> 00:26:54,760 like it and it doesn't grow very well there, which means you get a lot of preservation of hair. 232 00:26:55,400 --> 00:27:02,680 We also know at contemporary crime scenes, we recover scalp hair. I've recovered beard hair, 233 00:27:02,680 --> 00:27:11,240 like a full-length beard at a crime scene before. So we have hair available to us. 234 00:27:11,800 --> 00:27:16,680 One of the reasons anthropologists should care about hair in terms of human identification 235 00:27:17,320 --> 00:27:22,680 is that it provides us the most recent information about a person's diet and geography. 236 00:27:22,680 --> 00:27:33,000 So if we think about our teeth, you know, your teeth are the same teeth that you grew and developed 237 00:27:33,000 --> 00:27:40,600 when they first came in. So our tooth enamel can decay or erode, but we don't really grow new tooth 238 00:27:40,600 --> 00:27:46,600 enamel. So I always joke, don't be buying that toothpaste that tells you it's going to regrow 239 00:27:46,600 --> 00:27:54,680 your enamel because it's just not true. So what's great about the static nature of our tooth enamel 240 00:27:54,680 --> 00:28:00,680 is that it records our lived experiences in our childhood when those teeth are growing and 241 00:28:00,680 --> 00:28:09,720 developing. And so that becomes sort of a permanent record that we have of what we were eating and 242 00:28:09,720 --> 00:28:14,520 where we were eating it at the time those teeth were developing. So when we're talking about our 243 00:28:14,520 --> 00:28:19,080 permanent teeth, we're usually looking at, you know, between two and eight years old, depending 244 00:28:19,080 --> 00:28:27,880 upon the tooth, right? When you think about bone, our bones are alive and growing. So they respond 245 00:28:27,880 --> 00:28:34,600 to our activities, which means you kind of make yourself new bones every so often, and that's a 246 00:28:34,600 --> 00:28:42,440 slow but ongoing process. And so our bones are sort of that cumulative of our lived experiences 247 00:28:42,440 --> 00:28:49,080 over that turnover or regrowth time period. And it really depends upon which skeletal element that 248 00:28:49,080 --> 00:28:55,880 you're sampling. And of course, there are a lot of lived experiences and factors that go into that 249 00:28:55,880 --> 00:29:00,760 as well, but you're looking at a greater time span, right? So anything, you know, between 10 250 00:29:00,760 --> 00:29:07,960 and 30 years, depending upon which bone you're sampling. But your hair, your scalp hair grows at 251 00:29:07,960 --> 00:29:14,120 about a centimeter a month, which means in a strand of hair, if you chopped it into little 252 00:29:14,120 --> 00:29:20,280 one centimeter segments, however long that strand of hair is, you're going to have that many months 253 00:29:20,840 --> 00:29:28,600 of lived experiences recorded. So what that affords us is the opportunity to build a lifetime 254 00:29:29,320 --> 00:29:34,200 history. We can take those teeth and look at childhood, we can take the bones and look at 255 00:29:34,200 --> 00:29:41,000 sort of that overall lived experience over the last however many years. And then the hair again 256 00:29:41,000 --> 00:29:49,160 in those one centimeter segments gives us a monthly recap. And so we can build that lifetime 257 00:29:49,160 --> 00:30:01,080 history with that information. So what I think is really cool is that, you know, we used this as a 258 00:30:01,080 --> 00:30:08,280 tool in archaeology to tell us about people's lived experiences, right? There's not a way to double 259 00:30:08,280 --> 00:30:15,960 check whether or not we got it right. You know, we can use that information to support that story 260 00:30:15,960 --> 00:30:22,040 we're telling about the past through our archaeological work. And we have other lines of 261 00:30:22,040 --> 00:30:28,440 evidence that may support that story as well, but there's not a double check. When we start applying 262 00:30:28,440 --> 00:30:37,800 these theories to forensics, the stakes are different. So what that means is this technique 263 00:30:37,800 --> 00:30:46,680 has to stand up to that rigor and scrutiny. And if we get it wrong, there's potentially a major 264 00:30:46,680 --> 00:30:53,800 consequence. The consequence is that someone is going to go unidentified, right? So there's still 265 00:30:53,800 --> 00:31:01,640 going to be a person who's unidentified, whose family or loved ones are still waiting for answers 266 00:31:01,640 --> 00:31:09,320 about them. So for that reason, we really have to ask questions like, does this work the way we think 267 00:31:09,320 --> 00:31:18,280 it's going to? So that was a very long drawn out way of saying, we got to make sure it works in all 268 00:31:18,280 --> 00:31:26,120 of these different situations. And that was the driving force behind my dissertation was saying, 269 00:31:26,120 --> 00:31:32,520 does this work the way we think it's going to? A body donation program like the one at the 270 00:31:32,520 --> 00:31:39,880 University of Tennessee in Knoxville for the body farm or the anthropology research facility 271 00:31:40,840 --> 00:31:46,600 is an ideal place for this because people pre-register. I was thinking about this, 272 00:31:46,600 --> 00:31:52,840 pre-register. So they have thousands of people who are so excited about forensic science that 273 00:31:52,840 --> 00:31:58,760 they've elected to pre-register as body donors upon death. And part of that pre-registration 274 00:31:58,760 --> 00:32:05,560 process is to provide living information, anti-mortem data. And so some of the questions they ask are 275 00:32:05,560 --> 00:32:12,360 about lifetime residence histories and are about, do you have any kind of special diet? And so we can 276 00:32:12,360 --> 00:32:21,320 ground truth the isotopic results that we get looking at that data that was self-reported 277 00:32:21,320 --> 00:32:26,680 by these people when they were alive. And so it's an ideal place to do this kind of research because 278 00:32:26,680 --> 00:32:33,640 there's a way to double check yourself. And so my advice to somebody who's looking for an avenue of 279 00:32:33,640 --> 00:32:41,480 research related to isotopes would be to think about how have we been using this tool and where 280 00:32:41,480 --> 00:32:46,360 are the question marks that we still have? And I'll tell you, there are quite a few. There's a 281 00:32:46,360 --> 00:32:51,400 lot of ways that we can look at this and say, is this tool telling us what we think it is? 282 00:32:53,160 --> 00:32:58,840 One really important area, I think, is just the overall expansion of the data sets that we have 283 00:32:58,840 --> 00:33:03,800 because when you talk about this person looks local or this person looks non-local, 284 00:33:03,800 --> 00:33:11,960 local versus non-local can be a very broad category. It can be US or non-US, or it could be 285 00:33:12,760 --> 00:33:23,160 Tennessee or New Mexico, or it could be US versus Europe. So our data and our comparisons are only 286 00:33:23,160 --> 00:33:28,280 as good as the data sets that we have. So finding ways to expand those data sets, whether it is 287 00:33:28,280 --> 00:33:35,320 through environmental comparisons or through questions that involve isotopic analyses of 288 00:33:35,320 --> 00:33:38,920 human samples, I think there's a lot of room for us to grow the field. 289 00:33:40,040 --> 00:33:48,040 I know one topic that I've been trying to wrap my own brain around of how can I get at the answer, 290 00:33:48,040 --> 00:33:55,640 I guess, is you were talking about how your teeth are your childhood, your hair is the last couple 291 00:33:55,640 --> 00:34:01,160 of months, depending on how long it is. But within the field of anthropology, we don't really know 292 00:34:01,160 --> 00:34:08,200 how fast bone turns over because there's so many different factors that come into play of why bone 293 00:34:10,200 --> 00:34:15,080 turns over to begin with, where your ribs are constantly moving, so are they turning over 294 00:34:15,080 --> 00:34:20,280 faster than your legs and your arms and different things like that? But it's never really, 295 00:34:20,280 --> 00:34:25,000 or at least from all the literature that I've read, there's never been a clear answer of like, 296 00:34:26,600 --> 00:34:34,680 you know, people think, oh, the last five, 10 years, but is that at the mid shaft? Is that at, 297 00:34:34,680 --> 00:34:41,160 you know, your epiphysis or the ends of your bones? Those like trying to really get at how bone turns 298 00:34:41,160 --> 00:34:46,200 over, I think, even if you're not necessarily like interested in isotopes, I think isotopes is a 299 00:34:46,200 --> 00:34:53,560 fabulous avenue to try to figure that out, because you can see, you know, if you happen to have access 300 00:34:54,120 --> 00:35:01,400 to skeletal remains that you can do multiple destructive testing on, to like get at that 301 00:35:01,960 --> 00:35:07,080 turnover by sampling various parts of bone, various different aspects of bone throughout the body, 302 00:35:07,080 --> 00:35:12,440 and trying to get at how fast that person turned over, especially if you know their lived history. 303 00:35:12,440 --> 00:35:17,640 And so I know like, that's one that I've been like, oh, I just want to know, like, because we, 304 00:35:18,760 --> 00:35:25,080 like, for the research that I've done so far is like, trying to figure out, you know, is it all 305 00:35:25,080 --> 00:35:32,760 one person? Or do I have coomingling in my assemblage? And when you're like, well, I'm testing 306 00:35:32,760 --> 00:35:38,120 this bone versus this bone to say it's one person, but I don't really know how those bones turn over. 307 00:35:38,120 --> 00:35:45,400 So is this reliable? Is this like actually getting at what I want it to get at? And I know my brain 308 00:35:45,400 --> 00:35:51,480 constantly is just like, about all of it, because it's just like, there's so much that can be done 309 00:35:51,480 --> 00:36:01,640 with isotopes, which is exciting. I guess you're saying, because this is kind of the part that I've 310 00:36:01,640 --> 00:36:10,520 never done in any of my isotope research is I don't really go to court. So my experience with 311 00:36:10,520 --> 00:36:16,600 like how the public use isotopes and, you know, do they trust it? Do they not? Those types of things 312 00:36:17,240 --> 00:36:22,600 is just from tours at the lab of being like, it's so cool, you are what you need. And then like, 313 00:36:22,600 --> 00:36:27,880 no one really asks more questions than that, because they're so overwhelmed with data. But 314 00:36:27,880 --> 00:36:38,200 they're so overwhelmed with data. But how do you find that like, in a public forum, like court 315 00:36:38,200 --> 00:36:46,440 testimony, do people view isotopes? I think that's a good question. And, you know, I get the question 316 00:36:46,440 --> 00:36:52,600 pretty frequently in general, as a forensic anthropologist about, you know, what's it like 317 00:36:52,600 --> 00:37:03,720 to testify? And I've never testified on a forensic case. And, you know, I've done hundreds of cases 318 00:37:03,720 --> 00:37:11,080 at this point. But I think, you know, it depends on what the question is with your case, and the 319 00:37:11,080 --> 00:37:16,040 contentious nature of that question, right? I think that's the most important piece. So 320 00:37:16,040 --> 00:37:24,760 most of the time, as anthropologists utilizing the tool of isotopes for forensics, we're trying to 321 00:37:24,760 --> 00:37:31,320 make an identification. And so once that identification is made, you know, we're not 322 00:37:31,320 --> 00:37:36,200 going to use isotopes to individualize that identification. We're going to use some other 323 00:37:36,200 --> 00:37:43,160 means like anti-mortem record comparison, like either, you know, x-rays of the bones or dental 324 00:37:43,160 --> 00:37:51,720 records or DNA. We're going to use that as our formal means of identification. The bio profile 325 00:37:51,720 --> 00:37:58,200 that the anthropologist prepares, and maybe even the isotope analysis as an additional piece of 326 00:37:58,200 --> 00:38:05,320 information, is going to help with identification. So it's not going to help with the what happened 327 00:38:05,320 --> 00:38:13,880 to this person piece, which is usually what winds up being the contested portion of the 328 00:38:13,880 --> 00:38:21,800 anthropologist's work in court. Now, that's not to say that the technique of isotope analysis 329 00:38:21,800 --> 00:38:29,000 should not stand up to the rigorous examination that we give in court. It absolutely should, 330 00:38:29,000 --> 00:38:36,920 and it should be a tool that has repeatable results and that we're able to produce error rates and 331 00:38:36,920 --> 00:38:43,400 things like that on. And, you know, and it's still new. So we're still working on that information, 332 00:38:43,400 --> 00:38:48,920 and that's something that we have to continue demanding of those people who are utilizing the 333 00:38:48,920 --> 00:38:58,360 tool for forensic purposes. Now, that doesn't mean there aren't applications for this. So 334 00:38:58,360 --> 00:39:07,480 I'm thinking specifically about a case from a few years ago where neglect and abuse was alleged. 335 00:39:07,480 --> 00:39:15,480 And so we know that nitrogen values can potentially be higher in individuals who are malnourished. 336 00:39:15,480 --> 00:39:24,600 So measuring isotope ratios of nitrogen from hair samples, for example, is frequently used for 337 00:39:24,600 --> 00:39:30,440 people who are being treated for eating disorders, who might not be able to reliably report 338 00:39:30,440 --> 00:39:37,720 their own diets throughout the course of treatment. And so by measuring isotopes, nitrogen isotopes, 339 00:39:37,720 --> 00:39:43,720 you can sort of track that. People essentially sort of self-digest when they're malnourished, 340 00:39:43,720 --> 00:39:51,560 and so those nitrogen values get a little higher. And so in principle, you might be able to analyze 341 00:39:51,560 --> 00:40:04,120 those nitrogen values and prove or disprove neglect or malnourishment. The finite data on that, 342 00:40:04,120 --> 00:40:13,320 you know, is debatable. And so, you know, does that stand up to a rigorous examination in court? 343 00:40:13,320 --> 00:40:19,880 Are we able to confidently say that? And so that would be an example of something 344 00:40:19,880 --> 00:40:27,640 where it would be on the practitioner who's reporting those results to explain to a jury, 345 00:40:27,640 --> 00:40:33,880 hey, this is what isotopes are, and go through that whole introductory lesson that we gave here 346 00:40:33,880 --> 00:40:43,240 in an accessible way, you know, to a jury of people with basic education to help them 347 00:40:43,240 --> 00:40:49,400 understand what isotopes are and how they could potentially tell us this information. And then 348 00:40:49,400 --> 00:40:58,200 also provide us scientific evidence that shows that this is something that has been tested and 349 00:40:58,200 --> 00:41:02,920 is reproducible. And again, you know, that big question, is it telling us what we think it's 350 00:41:02,920 --> 00:41:07,160 telling us? So, you know, there'd have to be a lot of great care, I think, if we were going to 351 00:41:07,160 --> 00:41:13,400 accuse someone of a crime using isotopes. So is it that it hasn't been used in a court of law yet 352 00:41:13,400 --> 00:41:20,040 because it hasn't passed the admissibility criteria, or is it just that you yourself haven't? 353 00:41:20,040 --> 00:41:29,960 I personally have never been asked to address a question like that with isotopes. And, you know, 354 00:41:29,960 --> 00:41:37,320 and even in the cases where we're using this to provide leads for identification, you know, 355 00:41:37,320 --> 00:41:42,920 that, again, that's not really contested. You know, one other point to make, though, is lots 356 00:41:42,920 --> 00:41:47,960 of people are jumping on the isotopes bandwagon. You know, a lot of people are super excited about 357 00:41:47,960 --> 00:41:53,320 this as a tool that can be used. So you have labs that have been traditionally using isotopes 358 00:41:53,320 --> 00:42:00,120 archaeologically, who are now shifting to saying, oh, well, we can provide this service for forensic 359 00:42:00,120 --> 00:42:12,680 questions as well. And because there is not one cookbook recipe for all the steps involved in 360 00:42:12,680 --> 00:42:21,240 sample selection, sample preparation, and analytical methods, and even interpretations, 361 00:42:21,240 --> 00:42:30,600 because there's not a standard way of doing that, we've got people doing it all different ways. 362 00:42:31,480 --> 00:42:40,360 And so, you know, you have to be very cautious about which laboratories are providing information 363 00:42:41,640 --> 00:42:50,200 for forensic purposes. Are those laboratories used to being asked to address questions 364 00:42:50,200 --> 00:42:56,680 forensically and understand fully, you know, the gravity of that responsibility, and also that 365 00:42:56,680 --> 00:43:03,000 responsibility toward reproducibility of results, accounting for your methodologies, and all of those 366 00:43:03,000 --> 00:43:11,400 things. So, you know, this is something that I think could be a potential problem, right? Because, 367 00:43:11,400 --> 00:43:18,200 you know, there are a lot of tools that have been used forensically maybe once or twice. And then, 368 00:43:18,200 --> 00:43:27,560 you know, someone shows that there's not that repeatability piece of this that's so essential 369 00:43:28,440 --> 00:43:35,320 for scientific rigor. And it's like that technique gets a big black eye. And then ever more, 370 00:43:35,320 --> 00:43:41,560 even if it's the most useful technique, you know, in the back of the mind of the average person, 371 00:43:41,560 --> 00:43:48,520 or, you know, the court system, or science in general, it's always like, but it didn't really 372 00:43:48,520 --> 00:43:55,320 work, or can we really trust it? And so, that trust is such an important piece of forensic practice. 373 00:43:55,800 --> 00:44:03,320 And so, that's why we have to stepwise evaluate if the tool is telling us what we think it is, 374 00:44:03,320 --> 00:44:08,280 right? And so, that's why this is a wide open field for people who want to do research, 375 00:44:08,280 --> 00:44:12,040 because we've got to validate all of these methods. We've got to try it this way and that way, 376 00:44:12,040 --> 00:44:17,320 and see which way works the best. And then we as a field have to agree on this is how we're going to 377 00:44:17,320 --> 00:44:24,520 do it. So, I mean, along those same lines, you know, the field of all of the fields of 378 00:44:24,520 --> 00:44:30,360 forensic science are, we're going through the entire Academy standards boards, we're 379 00:44:31,080 --> 00:44:37,000 standardizing everything down to how we put a postage stamp on an envelope. Is this something 380 00:44:37,000 --> 00:44:46,520 that should be on their radar? Yes, and it is. I think that's a great question. So, 381 00:44:47,160 --> 00:44:57,640 you know, in response to the now notorious 2009 NAS report, scientific working groups 382 00:44:57,640 --> 00:45:02,680 were established for various fields in forensic science. Those scientific working groups have 383 00:45:02,680 --> 00:45:11,480 since been converted into the Organization of Scientific Area Committees, or the OSAC, 384 00:45:11,480 --> 00:45:20,600 for forensic sciences. And so, the OSAC is sort of works alongside NIST. So, the National Institute 385 00:45:20,600 --> 00:45:27,480 of Standards and Technology sort of helps facilitate OSAC meetings. So, these groups, 386 00:45:27,480 --> 00:45:35,080 I'm a member of the OSAC Subcommittee for Forensic Anthropology, and we are currently working on 387 00:45:35,960 --> 00:45:41,720 standards for isotope analysis. So, that is something that is actively happening now. 388 00:45:42,280 --> 00:45:47,720 And that's something that, you know, I would strongly encourage, regardless of whether you 389 00:45:47,720 --> 00:45:55,080 want to learn more about isotope analysis, or effective reporting as a forensic practitioner, 390 00:45:55,080 --> 00:46:01,000 or, you know, the do's and don'ts of DNA analysis, all of those have standards and best practices 391 00:46:01,000 --> 00:46:08,120 that are either in progress or have been published. And so, that's a really fantastic way to find out 392 00:46:08,120 --> 00:46:15,480 what the official sort of position on how you do these things is. And, you know, that's not to say 393 00:46:15,480 --> 00:46:23,000 there aren't still a lot of holes, a lot of gaps that need to be filled in that. But certainly, 394 00:46:23,000 --> 00:46:31,320 I think it's a strong response to a very valid critique of forensic science practice. 395 00:46:32,040 --> 00:46:36,360 So, yeah, I'm pretty sure that one just came out about isotopes not that long ago 396 00:46:37,240 --> 00:46:43,960 for like report writing and things like that that I read. And I mean, that's a great call for anyone 397 00:46:43,960 --> 00:46:48,280 within the field of anthropology as a whole to always go give your comments for those standards, 398 00:46:48,280 --> 00:46:54,600 because, you know, it can get published. And if your opinion wasn't given, then it's not going 399 00:46:54,600 --> 00:47:03,160 to be accounted for, and trying to make the standard as whole as possible. So, we're kind 400 00:47:03,160 --> 00:47:09,240 of coming up on our hour mark. I want to, you know, respect both our guest time and our listeners 401 00:47:09,240 --> 00:47:17,480 time. So, kind of just want to recap and say thank you so much for coming on and explaining 402 00:47:17,480 --> 00:47:24,600 what is a very broad and interesting topic in a way that I think, and I hope that our listeners, 403 00:47:24,600 --> 00:47:30,520 you know, can really understand and maybe it piques some interest and gave them some questions, 404 00:47:30,520 --> 00:47:34,520 which I think is always the best part about forensic science is like you listen to something 405 00:47:34,520 --> 00:47:41,000 and you're like, oh, wait, I have more questions on that. And then that is the basic basis of all 406 00:47:41,000 --> 00:47:47,880 research. So, just want to thank everyone for coming. If you, you know, our listeners have any 407 00:47:47,880 --> 00:47:53,560 more topics that you want us to talk about, if you want more isotope, we can always, you know, 408 00:47:53,560 --> 00:47:58,680 have a part two or part three or whatever if you have more specific questions. But you can also 409 00:47:58,680 --> 00:48:08,200 always email us at our email that's in the link. And then I'm going to poke and call and see if 410 00:48:08,200 --> 00:48:15,320 Tiffy, you'd be willing to give your email as well. We can add it to the kind of description 411 00:48:15,320 --> 00:48:20,600 for this podcast to see if like anyone has any specific questions that they would like to ask 412 00:48:20,600 --> 00:48:25,800 you maybe about, you know, your work in Tanzania or, you know, your work with Vanderbilt or even 413 00:48:26,680 --> 00:48:33,800 the body farm, if they could reach out to you specifically. But yeah, I think that's really it. 414 00:48:33,800 --> 00:48:41,480 If anyone has any last minute comments or whatever they want to make. Yeah, I don't know about you 415 00:48:41,480 --> 00:48:46,760 guys, but I just was inspired to write like five different proposals. That was such an interesting 416 00:48:46,760 --> 00:48:52,680 topic. I've never been a chemistry minded person. And that was like, I'm like exploding with ideas. 417 00:48:52,680 --> 00:48:56,840 My partner's not going to love me when I say that I want to quit my job and go back to school. But 418 00:48:56,840 --> 00:49:01,960 yeah, that was a really, really fascinating topic. And thank you so much, Dr. Tiffany Fracchia for 419 00:49:02,600 --> 00:49:09,960 giving us all that. That was awesome. Thank you so much. Well, you know, thanks for listening 420 00:49:09,960 --> 00:49:27,560 and we'll see you next time on the Bone Club. See y'all soon. Bye bye.