Analysis of the Accuracy of AncesTrees Software in Ancestry Estimation in Brazilian Identified Sample

Abstract

In the present study a software tool for craniometric ancestry estimation, An-cesTrees, was evaluated in an identified Brazilian skeletal sample with known self-reported ancestry. Twenty-three craniometric measures were obtained from each skull and analyzed using AncesTrees software, with two classification strategies-tournamentForest and ancestralForest algorithm. The tournament-Forest (53.54%) and ancestralForest algorithms with three ancestry groups (50.96%) were more accurate to classify Europeans, while the ancestralForest algorithm with six (50.00%) and two (67.64%) groups were more accurate to estimate the ancestry of African descents. Admixed ancestry specimens were classified predominantly as European descent. The use of the ancestralForest algorithm considering only European and African origin (58.42%) was the most accurate setup for ancestry estimation in Brazilian skulls. Supervised classification algorithms and tools such as the AncesTrees work based on data analysis and pattern matching, and there is no Brazilian sample in its database, the software showed a low accuracy Brazilian samples. The incorporation of representative craniometric data obtained from Brazilian skulls into the software database may significantly increase the accuracy of ancestry estimates.

Ancestry Estimation: Advances and Limitations in Forensic Applications

“…5,122 In their study on dry crania from a South African sample (Black, White and Coloured), Stull et al 39 refuted the claim that highly mixed populations cannot achieve high classification accuracy by producing classification rates of just over 80%. Moreover, in a validations study on Ancestrees performed by Fernandes et al, 123 a lower classification accuracy rate was obtained for a Brazilian sample likely due to the mixed ancestry of the individuals and the non-representation of this group in the software database. In addition, individuals from different parts within the same geographical areas (eg, Northern and Southern Mexican individuals) were shown to be associated to different reference samples when using FORDISC.3 with Latin American individuals showing overall lower posterior probabilities than Whites and African Americans.…”

Population affinity estimation on a Spanish sample: Testing the validity and accuracy of cranium and mandible online software methods

“…Thus, when the data permitted, the required craniometric values for the respective parameters were manually entered into AncesTrees for each of the 114 individuals in the sample [26]. For consistency and to facilitate better comparison to validation studies already published on this method [21], the left-side value was used. When the left side measurement was not available, the right side was used instead.…”

“…Regarding the metric approach, its objectivity based on the nature of data collection has been acknowledged and extensive research has been conducted [11][12][13]17,18]. Moreover, from all the skeletal elements used for population affinity estimation, the cranial skeleton is considered the most suitable as it might not be as environmentally affected as the postcranial elements [10,[19][20][21]. Thus, the number of metric methods developed using the cranium has increased in the last decade, with techniques using traditional methods employing discriminant function analysis as well as computerized methods being developed from large reference samples [12,17,18,22].…”

“…Thus, the number of metric methods developed using the cranium has increased in the last decade, with techniques using traditional methods employing discriminant function analysis as well as computerized methods being developed from large reference samples [12,17,18,22]. Considering the effect that population affinity has on the ensuing estimations and the emerging number of population affinity estimation methods, validation studies are required to ensure accurate and reliable results [21][22][23][24][25].…”

Estimativa da ancestralidade pelo crânio na população brasileira – revisão de literatura

“…6 teve como objetivo verificar a acurácia do AncesTress, pela comparação dos resultados do software com os registros prévios de 114 crânios, oriundos do estado de São Paulo. O autor constatou uma acurácia de 48% a 70%, dependendo da configuração dos grupos ancestrais.A análise de 266 crânios brasileiros identificados realizado por Fernandes29 , avaliou a precisão do software AncesTress e mostrou a prevalência do algorítimo AncestralForest com maior confiabilidade na estimativa de ancestralidade da amostra. Tal resultado reforça a importância de dados amostrais em softwares que são utilizados para estimativa de ancestralidade, de forma a aproximar os resultados das análises à realidade da população brasileira, contribuindo de forma relevante para o trabalho de peritos forenses que operam no Brasil.O método realizado por meio da análise dos dentes foi aplicado em estudos realizados na Região Nordeste do país.…”