Mitochondrial DNA analysis of ancient sheep from Kazakhstan: evidence for early sheep introduction

Abstract

Kazakhstan covers a vast territory, and it has always been a land of nomadic pastoralism, where domesticated horses and sheep were moved by nomadic people across the steppe. Previous reports suggest that sheep breeds from Kazakhstan have an intermediate genetic composition between Asian and European breeds; however, this data appears to be limited. Therefore, we studied the genetic diversity of ancient domestic sheep from two Late Bronze Age settlements, Toksanbai and Kent, located in the Pre-Caspian region of Kazakhstan and central Kazakhstan, respectively. We have applied ZooMS analysis for taxonomic identification of small ruminant remains to select ancient specimens of domestic sheep (Ovis aries). To assign sheep mitochondrial DNA (mtDNA) haplogroups, the single nucleotide polymorphisms (SNPs) from the control region were analyzed by real-time PCR and direct sequencing. Identical distribution of mtDNA haplogroups A (8/14; 57%), B (5/14; 36%), and C (1/14; 7%) was observed in the specimens from Toksanbai (n ¼ 14) and Kent (n ¼ 14). Ovine haplogroup A was predominant in both settlements. Both archeological sites had similar patterns of haplogroup distribution, indicating early sheep introduction into the region. These results are important to gain a better understanding of sheep migrations in the Eurasian steppe and highlight the importance of genomic analysis of earlier local lineages.