Sex estimation methods using traditional cranial nonmetric traits utilize predictive models to pr... more Sex estimation methods using traditional cranial nonmetric traits utilize predictive models to produce a final sex estimation, using the resulting model's score to classify the individual. When sex estimations are assigned from discriminant scoring alone, statistical confidence in the resultant estimate is not always assessed or reported. Although some forensic anthropologists may qualitatively report their confidence in the assessment (e.g., “probable male”), these statements are subjective, not standardized, and not necessarily based on statistical results in a uniform way. The goals of this study were to evaluate how posterior probability‐informed thresholds (PPITs) impacted accuracy rates, assess the balance between sample inclusion and accuracy for the proposed PPIT approach, and make recommendations for the use and interpretation of specific thresholds in casework. Using a sample of U.S. Black and White females and males (n = 292), we examined how PPITs can standardize the decision‐making process of inferring sex for two methods using nonmetric cranial traits. We found that using PPITs of at least 0.85 increased accuracy (over 92% for some PPITs) yet remained highly inclusive of the sample. PPITs < 0.75 did not produce classification accuracy rates significantly higher than chance, and when using these cranial trait sex estimation methods, cases with posterior probabilities (PPs) <0.75 should be reported as “indeterminate.” The 0.75–0.84 PPIT interval had an accuracy rate of 76%, which was both statistically significantly different from chance as well as from the higher (>0.85) groups, suggesting that although sex estimation at this level may be acceptable, the results hold lower confidence.
The purpose of this study was to investigate the accuracy rates and trends in forensic anthropolo... more The purpose of this study was to investigate the accuracy rates and trends in forensic anthropology casework concerning the estimation of the biological profile (sex, age, ancestry, and stature). Identified cases from the Forensic Anthropology Database for Assessing Methods Accuracy (FADAMA; n = 359) were analyzed to explore the following: accuracy rates per biological profile component, case‐level performance in assessing the biological profile, and factors related to inaccuracy rates. Accuracy rates for the four biological profile components ranged from 83% to 98%, with sex estimation performing the best and stature performing the poorest. While the overall sex estimation inaccuracies were the lowest of any biological profile component, we found that females are missexed approximately ten times more often than males. Inaccurate age estimates were more frequently the result of overestimation than underestimation, while the trends are reversed for stature estimation. Regarding ancestry estimation performance, African American/Black and White decedents had the lowest inaccuracy rates, while Hispanic and Asian/Pacific Islander decedents demonstrated greater inaccuracy rates. When examining accuracy rates for each case, 81% of cases had no inaccurate biological profile estimates, while 17% and 2% inaccurately estimated one and two biological profile components, respectively. The demographic trends of identified forensic anthropology cases reflect the national unidentified decedent demographics. Biological profile accuracy rates were generally comparable to previous studies. The findings highlight the current status of forensic anthropologists’ casework performance, with a greater amount of case‐level inaccuracy rates than previously thought, and demonstrate the potential methodological and sampling strategies that could improve accuracy rates.
We report on the functionality, available support, and research capability of the Forensic Anthro... more We report on the functionality, available support, and research capability of the Forensic Anthropology Database for Assessing Methods Accuracy (FADAMA; DOJ
Racial disparities in the US criminal justice system (CJS) have been extensively documented in sc... more Racial disparities in the US criminal justice system (CJS) have been extensively documented in scholarly work. Critical race scholars have suggested that color-blind racial attitudes inform the set of beliefs that CJS practitioners use in decision making. If this is the case, factors that are related to color-blind racial attitude trends in CJS practitioners must be better understood. We focus on a single CJS practitioner—the police—to assess their color-blind racial beliefs and compare these to the broader US public. Using the Color-Blind Racial Attitudes Scale (CoBRAS), we identified sociodemographic variables associated with high CoBRAS scores in a multiracial lay sample (N = 1401; males and females, mean age = 33.4 years). Police (N = 112) and police recruits (N = 52) CoBRAS scores were compared to CoBRAS scores of lay participants with similar sociodemographics as the police and recruit samples, (respectively, N = 451; N = 291). Police scored significantly higher on the CoBRAS than laypersons even when controlling for sociodemographic variables. Police recruits also have higher CoBRAS scores than laypersons, again controlling for sociodemographic variables. These findings suggest that police work attracts people who endorse color-blind racial beliefs. These findings make understanding the relationship between color-blind racial beliefs and discriminatory behavior of CJS practitioners imperative.
Based on mitochondrial DNA (mtDNA), it has been estimated that at least 15 founder hap-logroups p... more Based on mitochondrial DNA (mtDNA), it has been estimated that at least 15 founder hap-logroups peopled the Americas. Subhaplogroup C1d3 was defined based on the mitogen-ome of a living individual from Uruguay that carried a lineage previously identified in hypervariable region I sequences from ancient and modern Uruguayan individuals. When complete mitogenomes were studied, additional substitutions were found in the coding region of the mitochondrial genome. Using a complete ancient mitogenome and three mod-ern mitogenomes, we aim to clarify the ancestral state of subhaplogroup C1d3 and to better understand the peopling of the region of the Río de la Plata basin, as well as of the builders of the mounds from which the ancient individuals were recovered. The ancient mitogenome, belonging to a female dated to 1,610±46 years before present, was identical to the mitogen-ome of one of the modern individuals. All individuals share the mutations defining subha-plogroup C1d3. We estimated ...
Recent genotypic analyses of U.S.-Mexico border-crossing fatalities reveal greater indigenous anc... more Recent genotypic analyses of U.S.-Mexico border-crossing fatalities reveal greater indigenous ancestry in individuals who are currently unidentified and have been recovered in more recent years—called an “identification bias” in the forensic case analysis of Hispanics of Mexican origin. Given the implications of these findings for the human identification process, this study uses craniometrics to validate these genotypic results. We test if the dynamic temporal, geographic, and identification trends in Hispanic casework revealed with genetic ancestry information can be reproduced with ancestry estimates derived from the cranium. We find an inverse relationship between the amount of European and Native American ancestry and an increased representation of peoples with more Native American ancestry in more recent years. Our results support the identification bias as the individuals with greater Native American ancestry are less likely to have complete case information, particularly birthplace, on record and are more often assigned low identity status scores. KEYWORDS: ancestry, Admixed Native American, Hispanic population, Latin America, U.S.-Mexico border, undocumented migrant deaths, skeletal identification, geographic structure, temporal trends, craniometrics, genetics
Unprovenanced skeletal remains were located by law enforcement in a private residence in rural Mi... more Unprovenanced skeletal remains were located by law enforcement in a private residence in rural Missouri. Forensic anthropological assistance was requested to determine the origin and medicolegal significance of the material. The homeowner provided written documentation that the remains were legally obtained from an archaeological site in Guatemala; however, police expressed concern they were actually illegally looted and retained from a local historic African American cemetery. The recovered skeletal material was inventoried and a minimum number of individuals established based on crania and cranial fragments. The ten most complete crania were subject to further analyses. Assessment of biological profile, DNA analyses, and stable isotopes were utilized by three forensic anthropological practitioners to address three hypotheses of potential origin. Based on the collaborative results, none of the recovered skeletal material tested was from the proposed region of Iztapa, Guatemala. Data indicate that at least two of the recovered crania cannot be ruled out as being from the historic African American cemetery. However, results show it is likely the skeletal material is representative of multiple historic sites within the central and eastern Missouri region. This case emphasizes the need for utility of collaboration within the forensic anthropological field. KEYWORDS: forensic anthropology, stable isotopes, DNA
Filipinos represent a significant contemporary demographic group globally, yet they are underrepr... more Filipinos represent a significant contemporary demographic group globally, yet they are underrepresented in the forensic anthropological literature. Given the complex population history of the Philippines, it is important to ensure that traditional methods for assessing the biological profile are appropriate when applied to these peoples. Here we analyze the classification trends of a modern Filipino sample ( n = 110) when using the Fordisc 3.1 (FD3) software. We hypothesize that Filipinos represent an admixed population drawn largely from Asian and marginally from European parental gene pools, such that FD3 will classify these individuals morphometrically into reference samples that reflect a range of European admixture, in quantities from small to large. Our results show the greatest classification into Asian reference groups (72.7%), followed by Hispanic (12.7%), Indigenous American (7.3%), African (4.5%), and European (2.7%) groups included in FD3. This general pattern did not change between males and females. Moreover, replacing the raw craniometric values with their shape variables did not significantly alter the trends already observed. These classification trends for Filipino crania provide useful information for casework interpretation in forensic laboratory practice. Our findings can help biological anthropologists to better understand the evolutionary, population historical, and statistical reasons for FD3-generated classifications. The results of our study indicate that ancestry estimation in forensic anthropology would benefit from population-focused research that gives consideration to histories of colonialism and periods of admixture.
This study presents genetic data for nine Native American populations from northern North America... more This study presents genetic data for nine Native American populations from northern North America. Analyses of genetic variation focus on the Pacific Northwest (PNW). Using mitochondrial, Y chromosomal, and autosomal DNA variants, we aimed to more closely address the relationships of geography and language with present genetic diversity among the regional PNW Native American populations. Patterns of genetic diversity exhibited by the three genetic systems were consistent with our hypotheses: genetic variation was more strongly explained by geographic proximity than by linguistic structure. Our findings were corroborated through a variety on analytic approaches, with the unrooted trees for the three genetic systems consistently separating inland from coastal PNW populations. Furthermore, analyses of molecular variance support the trends exhibited by the unrooted trees, with geographic partitioning of PNW populations (FCT = 19.43%, p = 0.010 ± 0.009) accounting for over twice as much ...
Based on mitochondrial DNA (mtDNA), it has been estimated that at least 15 founder haplogroups pe... more Based on mitochondrial DNA (mtDNA), it has been estimated that at least 15 founder haplogroups peopled the Americas. Subhaplogroup C1d3 was defined based on the mitogenome of a living individual from Uruguay that carried a lineage previously identified in hypervariable region I sequences from ancient and modern Uruguayan individuals. When complete mitogenomes were studied, additional substitutions were found in the coding region of the mitochondrial genome. Using a complete ancient mitogenome and three modern mitogenomes, we aim to clarify the ancestral state of subhaplogroup C1d3 and to better understand the peopling of the region of the Río de la Plata basin, as well as of the builders of the mounds from which the ancient individuals were recovered. The ancient mitogenome, belonging to a female dated to 1,610±46 years before present, was identical to the mitogenome of one of the modern individuals. All individuals share the mutations defining subhaplogroup C1d3. We estimated an age of 8,974 (5,748-12,261) years for the most recent common ancestor of C1d3, in agreement with the initial peopling of the geographic region. No individuals belonging to the defined lineage were found outside of Uruguay, which raises questions regarding the mobility of the prehistoric inhabitants of the country. Moreover, the present study shows the continuity of Native lineages over at least 6,000 years.
The purpose of this study was to investigate the accuracy rates and trends in forensic anthropolo... more The purpose of this study was to investigate the accuracy rates and trends in forensic anthropology casework concerning the estimation of the biological profile (sex, age, ancestry, and stature). Identified cases from the Forensic Anthropology Database for Assessing Methods Accuracy (FADAMA; n = 359) were analyzed to explore the following: accuracy rates per biological profile component, case-level performance in assessing the biological profile, and factors related to inaccuracy rates. Accuracy rates for the four biological profile components ranged from 83% to 98%, with sex estimation performing the best and stature performing the poorest. While the overall sex estimation inaccuracies were the lowest of any biological profile component, we found that females are missexed approximately ten times more often than males. Inaccurate age estimates were more frequently the result of overestimation than underestimation, while the trends are reversed for stature estimation. Regarding ances...
The Combined DNA Index System (CODIS) loci are a standard microsatellite marker set widely used f... more The Combined DNA Index System (CODIS) loci are a standard microsatellite marker set widely used for distinguishing among individuals in forensic DNA identity testing for medico-legal casework in the United States and in other countries. In anthropological genetic research, CODIS markers have become an important tool for uses extending beyond case investigations to quantify ancestry proportions, reveals patterns of admixture and trace population histories. These investigations are especially prevalent in studies of Latin American population structure. Nevertheless, the accuracy of the ancestry estimates computed from the CODIS loci for highly admixed Latino populations has not been formally tested. Long-standing arguments have been made that small ancestry panels, including the CODIS loci specifically, are not suitable for ancestry inference in admixed populations, due to the high heterozygosity and limited number of the loci used. Recent studies on ancestry inference using the CODIS loci suggest that these do confer more information of population-level identifiability than recognized in forensic genetic scholarship and by the medico-legal community. Here, we formally test the ability of CODIS and CODIS-Proxy (e.g. high heterozygosity and individual identifiability loci) marker panels to accurately estimate admixture proportions of individuals, including a sample of Latinos with a wide range of ancestry proportions. Using the same individuals in order to make direct comparisons of the outcomes, we produce ancestry estimates from 1) a small CODIS/CODIS Proxy loci panel and 2) a robust and validated microsatellite ancestry informative panel. We find evidence (e.g. ρ = 0.80 to 0.88) that supports the use of CODIS/CODIS-Proxy loci to capture the general ancestry estimation trends of a sample. This finding is in line with what studies using CODIS on Latin American populations have found, in that the ancestry estimations generated by CODIS present trends supported by documented population histories (e.g. colonialism and
Assigning correct population affinity to a skeleton can contribute important information to an in... more Assigning correct population affinity to a skeleton can contribute important information to an investigation-yet recent work highlights high error rates when classifying Latinos with a traditional tool, Fordisc 3.1 (FD3). Our study examines whether misclassification trends exist, and whether these can be used to infer population affinity. We examine the relationships among ancestry, geography, and FD3 misclassifications of Latinos using canonical variate analysis and unsupervised model-based clustering of craniometrics. Northern Mexicans appear more strongly associated with FD3 references samples with elevated amounts of European ancestry (e.g., American Blacks and Whites), while Southern Mexicans are more strongly associated with FD3 reference samples with reduced amounts of European ancestry (e.g., Guatemalans and Native Americans). FD3 classifications revealed that Latinos exhibited lower posterior probabilities when compared to other common case demographics (Whites and African ...
Sex estimation methods using traditional cranial nonmetric traits utilize predictive models to pr... more Sex estimation methods using traditional cranial nonmetric traits utilize predictive models to produce a final sex estimation, using the resulting model's score to classify the individual. When sex estimations are assigned from discriminant scoring alone, statistical confidence in the resultant estimate is not always assessed or reported. Although some forensic anthropologists may qualitatively report their confidence in the assessment (e.g., “probable male”), these statements are subjective, not standardized, and not necessarily based on statistical results in a uniform way. The goals of this study were to evaluate how posterior probability‐informed thresholds (PPITs) impacted accuracy rates, assess the balance between sample inclusion and accuracy for the proposed PPIT approach, and make recommendations for the use and interpretation of specific thresholds in casework. Using a sample of U.S. Black and White females and males (n = 292), we examined how PPITs can standardize the decision‐making process of inferring sex for two methods using nonmetric cranial traits. We found that using PPITs of at least 0.85 increased accuracy (over 92% for some PPITs) yet remained highly inclusive of the sample. PPITs < 0.75 did not produce classification accuracy rates significantly higher than chance, and when using these cranial trait sex estimation methods, cases with posterior probabilities (PPs) <0.75 should be reported as “indeterminate.” The 0.75–0.84 PPIT interval had an accuracy rate of 76%, which was both statistically significantly different from chance as well as from the higher (>0.85) groups, suggesting that although sex estimation at this level may be acceptable, the results hold lower confidence.
The purpose of this study was to investigate the accuracy rates and trends in forensic anthropolo... more The purpose of this study was to investigate the accuracy rates and trends in forensic anthropology casework concerning the estimation of the biological profile (sex, age, ancestry, and stature). Identified cases from the Forensic Anthropology Database for Assessing Methods Accuracy (FADAMA; n = 359) were analyzed to explore the following: accuracy rates per biological profile component, case‐level performance in assessing the biological profile, and factors related to inaccuracy rates. Accuracy rates for the four biological profile components ranged from 83% to 98%, with sex estimation performing the best and stature performing the poorest. While the overall sex estimation inaccuracies were the lowest of any biological profile component, we found that females are missexed approximately ten times more often than males. Inaccurate age estimates were more frequently the result of overestimation than underestimation, while the trends are reversed for stature estimation. Regarding ancestry estimation performance, African American/Black and White decedents had the lowest inaccuracy rates, while Hispanic and Asian/Pacific Islander decedents demonstrated greater inaccuracy rates. When examining accuracy rates for each case, 81% of cases had no inaccurate biological profile estimates, while 17% and 2% inaccurately estimated one and two biological profile components, respectively. The demographic trends of identified forensic anthropology cases reflect the national unidentified decedent demographics. Biological profile accuracy rates were generally comparable to previous studies. The findings highlight the current status of forensic anthropologists’ casework performance, with a greater amount of case‐level inaccuracy rates than previously thought, and demonstrate the potential methodological and sampling strategies that could improve accuracy rates.
We report on the functionality, available support, and research capability of the Forensic Anthro... more We report on the functionality, available support, and research capability of the Forensic Anthropology Database for Assessing Methods Accuracy (FADAMA; DOJ
Racial disparities in the US criminal justice system (CJS) have been extensively documented in sc... more Racial disparities in the US criminal justice system (CJS) have been extensively documented in scholarly work. Critical race scholars have suggested that color-blind racial attitudes inform the set of beliefs that CJS practitioners use in decision making. If this is the case, factors that are related to color-blind racial attitude trends in CJS practitioners must be better understood. We focus on a single CJS practitioner—the police—to assess their color-blind racial beliefs and compare these to the broader US public. Using the Color-Blind Racial Attitudes Scale (CoBRAS), we identified sociodemographic variables associated with high CoBRAS scores in a multiracial lay sample (N = 1401; males and females, mean age = 33.4 years). Police (N = 112) and police recruits (N = 52) CoBRAS scores were compared to CoBRAS scores of lay participants with similar sociodemographics as the police and recruit samples, (respectively, N = 451; N = 291). Police scored significantly higher on the CoBRAS than laypersons even when controlling for sociodemographic variables. Police recruits also have higher CoBRAS scores than laypersons, again controlling for sociodemographic variables. These findings suggest that police work attracts people who endorse color-blind racial beliefs. These findings make understanding the relationship between color-blind racial beliefs and discriminatory behavior of CJS practitioners imperative.
Based on mitochondrial DNA (mtDNA), it has been estimated that at least 15 founder hap-logroups p... more Based on mitochondrial DNA (mtDNA), it has been estimated that at least 15 founder hap-logroups peopled the Americas. Subhaplogroup C1d3 was defined based on the mitogen-ome of a living individual from Uruguay that carried a lineage previously identified in hypervariable region I sequences from ancient and modern Uruguayan individuals. When complete mitogenomes were studied, additional substitutions were found in the coding region of the mitochondrial genome. Using a complete ancient mitogenome and three mod-ern mitogenomes, we aim to clarify the ancestral state of subhaplogroup C1d3 and to better understand the peopling of the region of the Río de la Plata basin, as well as of the builders of the mounds from which the ancient individuals were recovered. The ancient mitogenome, belonging to a female dated to 1,610±46 years before present, was identical to the mitogen-ome of one of the modern individuals. All individuals share the mutations defining subha-plogroup C1d3. We estimated ...
Recent genotypic analyses of U.S.-Mexico border-crossing fatalities reveal greater indigenous anc... more Recent genotypic analyses of U.S.-Mexico border-crossing fatalities reveal greater indigenous ancestry in individuals who are currently unidentified and have been recovered in more recent years—called an “identification bias” in the forensic case analysis of Hispanics of Mexican origin. Given the implications of these findings for the human identification process, this study uses craniometrics to validate these genotypic results. We test if the dynamic temporal, geographic, and identification trends in Hispanic casework revealed with genetic ancestry information can be reproduced with ancestry estimates derived from the cranium. We find an inverse relationship between the amount of European and Native American ancestry and an increased representation of peoples with more Native American ancestry in more recent years. Our results support the identification bias as the individuals with greater Native American ancestry are less likely to have complete case information, particularly birthplace, on record and are more often assigned low identity status scores. KEYWORDS: ancestry, Admixed Native American, Hispanic population, Latin America, U.S.-Mexico border, undocumented migrant deaths, skeletal identification, geographic structure, temporal trends, craniometrics, genetics
Unprovenanced skeletal remains were located by law enforcement in a private residence in rural Mi... more Unprovenanced skeletal remains were located by law enforcement in a private residence in rural Missouri. Forensic anthropological assistance was requested to determine the origin and medicolegal significance of the material. The homeowner provided written documentation that the remains were legally obtained from an archaeological site in Guatemala; however, police expressed concern they were actually illegally looted and retained from a local historic African American cemetery. The recovered skeletal material was inventoried and a minimum number of individuals established based on crania and cranial fragments. The ten most complete crania were subject to further analyses. Assessment of biological profile, DNA analyses, and stable isotopes were utilized by three forensic anthropological practitioners to address three hypotheses of potential origin. Based on the collaborative results, none of the recovered skeletal material tested was from the proposed region of Iztapa, Guatemala. Data indicate that at least two of the recovered crania cannot be ruled out as being from the historic African American cemetery. However, results show it is likely the skeletal material is representative of multiple historic sites within the central and eastern Missouri region. This case emphasizes the need for utility of collaboration within the forensic anthropological field. KEYWORDS: forensic anthropology, stable isotopes, DNA
Filipinos represent a significant contemporary demographic group globally, yet they are underrepr... more Filipinos represent a significant contemporary demographic group globally, yet they are underrepresented in the forensic anthropological literature. Given the complex population history of the Philippines, it is important to ensure that traditional methods for assessing the biological profile are appropriate when applied to these peoples. Here we analyze the classification trends of a modern Filipino sample ( n = 110) when using the Fordisc 3.1 (FD3) software. We hypothesize that Filipinos represent an admixed population drawn largely from Asian and marginally from European parental gene pools, such that FD3 will classify these individuals morphometrically into reference samples that reflect a range of European admixture, in quantities from small to large. Our results show the greatest classification into Asian reference groups (72.7%), followed by Hispanic (12.7%), Indigenous American (7.3%), African (4.5%), and European (2.7%) groups included in FD3. This general pattern did not change between males and females. Moreover, replacing the raw craniometric values with their shape variables did not significantly alter the trends already observed. These classification trends for Filipino crania provide useful information for casework interpretation in forensic laboratory practice. Our findings can help biological anthropologists to better understand the evolutionary, population historical, and statistical reasons for FD3-generated classifications. The results of our study indicate that ancestry estimation in forensic anthropology would benefit from population-focused research that gives consideration to histories of colonialism and periods of admixture.
This study presents genetic data for nine Native American populations from northern North America... more This study presents genetic data for nine Native American populations from northern North America. Analyses of genetic variation focus on the Pacific Northwest (PNW). Using mitochondrial, Y chromosomal, and autosomal DNA variants, we aimed to more closely address the relationships of geography and language with present genetic diversity among the regional PNW Native American populations. Patterns of genetic diversity exhibited by the three genetic systems were consistent with our hypotheses: genetic variation was more strongly explained by geographic proximity than by linguistic structure. Our findings were corroborated through a variety on analytic approaches, with the unrooted trees for the three genetic systems consistently separating inland from coastal PNW populations. Furthermore, analyses of molecular variance support the trends exhibited by the unrooted trees, with geographic partitioning of PNW populations (FCT = 19.43%, p = 0.010 ± 0.009) accounting for over twice as much ...
Based on mitochondrial DNA (mtDNA), it has been estimated that at least 15 founder haplogroups pe... more Based on mitochondrial DNA (mtDNA), it has been estimated that at least 15 founder haplogroups peopled the Americas. Subhaplogroup C1d3 was defined based on the mitogenome of a living individual from Uruguay that carried a lineage previously identified in hypervariable region I sequences from ancient and modern Uruguayan individuals. When complete mitogenomes were studied, additional substitutions were found in the coding region of the mitochondrial genome. Using a complete ancient mitogenome and three modern mitogenomes, we aim to clarify the ancestral state of subhaplogroup C1d3 and to better understand the peopling of the region of the Río de la Plata basin, as well as of the builders of the mounds from which the ancient individuals were recovered. The ancient mitogenome, belonging to a female dated to 1,610±46 years before present, was identical to the mitogenome of one of the modern individuals. All individuals share the mutations defining subhaplogroup C1d3. We estimated an age of 8,974 (5,748-12,261) years for the most recent common ancestor of C1d3, in agreement with the initial peopling of the geographic region. No individuals belonging to the defined lineage were found outside of Uruguay, which raises questions regarding the mobility of the prehistoric inhabitants of the country. Moreover, the present study shows the continuity of Native lineages over at least 6,000 years.
The purpose of this study was to investigate the accuracy rates and trends in forensic anthropolo... more The purpose of this study was to investigate the accuracy rates and trends in forensic anthropology casework concerning the estimation of the biological profile (sex, age, ancestry, and stature). Identified cases from the Forensic Anthropology Database for Assessing Methods Accuracy (FADAMA; n = 359) were analyzed to explore the following: accuracy rates per biological profile component, case-level performance in assessing the biological profile, and factors related to inaccuracy rates. Accuracy rates for the four biological profile components ranged from 83% to 98%, with sex estimation performing the best and stature performing the poorest. While the overall sex estimation inaccuracies were the lowest of any biological profile component, we found that females are missexed approximately ten times more often than males. Inaccurate age estimates were more frequently the result of overestimation than underestimation, while the trends are reversed for stature estimation. Regarding ances...
The Combined DNA Index System (CODIS) loci are a standard microsatellite marker set widely used f... more The Combined DNA Index System (CODIS) loci are a standard microsatellite marker set widely used for distinguishing among individuals in forensic DNA identity testing for medico-legal casework in the United States and in other countries. In anthropological genetic research, CODIS markers have become an important tool for uses extending beyond case investigations to quantify ancestry proportions, reveals patterns of admixture and trace population histories. These investigations are especially prevalent in studies of Latin American population structure. Nevertheless, the accuracy of the ancestry estimates computed from the CODIS loci for highly admixed Latino populations has not been formally tested. Long-standing arguments have been made that small ancestry panels, including the CODIS loci specifically, are not suitable for ancestry inference in admixed populations, due to the high heterozygosity and limited number of the loci used. Recent studies on ancestry inference using the CODIS loci suggest that these do confer more information of population-level identifiability than recognized in forensic genetic scholarship and by the medico-legal community. Here, we formally test the ability of CODIS and CODIS-Proxy (e.g. high heterozygosity and individual identifiability loci) marker panels to accurately estimate admixture proportions of individuals, including a sample of Latinos with a wide range of ancestry proportions. Using the same individuals in order to make direct comparisons of the outcomes, we produce ancestry estimates from 1) a small CODIS/CODIS Proxy loci panel and 2) a robust and validated microsatellite ancestry informative panel. We find evidence (e.g. ρ = 0.80 to 0.88) that supports the use of CODIS/CODIS-Proxy loci to capture the general ancestry estimation trends of a sample. This finding is in line with what studies using CODIS on Latin American populations have found, in that the ancestry estimations generated by CODIS present trends supported by documented population histories (e.g. colonialism and
Assigning correct population affinity to a skeleton can contribute important information to an in... more Assigning correct population affinity to a skeleton can contribute important information to an investigation-yet recent work highlights high error rates when classifying Latinos with a traditional tool, Fordisc 3.1 (FD3). Our study examines whether misclassification trends exist, and whether these can be used to infer population affinity. We examine the relationships among ancestry, geography, and FD3 misclassifications of Latinos using canonical variate analysis and unsupervised model-based clustering of craniometrics. Northern Mexicans appear more strongly associated with FD3 references samples with elevated amounts of European ancestry (e.g., American Blacks and Whites), while Southern Mexicans are more strongly associated with FD3 reference samples with reduced amounts of European ancestry (e.g., Guatemalans and Native Americans). FD3 classifications revealed that Latinos exhibited lower posterior probabilities when compared to other common case demographics (Whites and African ...
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