"Who were you ?": a genetic approach in the characterisation of biological identities

Abstract : Several types of biological information can be retrieved with  the  help  of  paleogenetics analyses, such as the biological sex of an individual, their mitochondrial haplotypes  or  their Y-chromosome one. These are important, firstly to assess other  sex-dependent  features  such as their size and age; moreover, to know the origin of their respectively maternai and paternal lineages, and finally to understand their identity as part of a group, i.e., their relationships and kinship with others [1, 2].

Morphological methods are often used to identify the sex of an individual, however, when this technique is applied to juveniles and infants it can be imprecise and unreliable [3]. To resolve this issue, several new techniques and technologies are now available, including paleogenomics and Shotgun Sequencing [4]. The latter can accurately identify the sex of an individual by comparing the fraction of sequences mapping on the Y chromosome to the total number of sequences aligned to the X and Y chromosomes [4, 5].

Lineages and migrations of people can be reconstructed with the help of traditional methods such as PCR or high-throughput sequencing [2, 6, 7]. lndeed, these methods allow the identification of the mitochondrial DNA haplotype, transmitted through the mother to descendants, and the Y-chromosome haplotype, transmitted through  the father  to male descendants. These can provide information about, firstly, what genetic group they are part of, and then, with the help of now constructed phylogenetic trees, where their lineage cornes from, what migration pathways the group took and how old it is [7]. Moreover, mtDNA and Y-chromosome haplogroups can give hints about the relationships, such as kinship of the maternai or paternal side of the family. Uniparental markers will not produce precise kinship proofs like nuclear markers could do [5], but they provide complementary information.

Such analyses combining sex and haplotypes determination have been undertaken in material recovered from several Eurasian archaeological sites to help us understand who the buried people were and any relationships between each other [8].

To conclude, new technologies and fields such as paleogenetics can help improve our understanding of archaeological remains  by providing more reliable information  about past people and their biological identity.