Аннотация
The Adai horse represents one of Kazakhstan’s valuable local genetic resources; however, molecular genetic data on the genetic diversity and population structure of individual farm populations remain limited. Therefore, this study aimed to assess the genetic diversity of three Adai horse populations and characterize their genetic structure using microsatellite markers. A total of 166 horses from the Mukhit (n=67), Darkhan (n=56), and Islam (n=43) farms were genotyped at 17 STR loci. Genetic diversity parameters were calculated using GenAlEx, while genetic relationships among the populations were assessed using factorial correspondence analysis (FCA) and Bayesian clustering. All investigated STR loci were polymorphic; the mean number of alleles was 8.510±0.298, the mean effective number of alleles was 5.008±0.209, and Shannon’s information index was 1.750±0.040. Observed heterozygosity ranged from 0.746 to 0.805 across populations, whereas expected heterozygosity ranged from 0.772 to 0.784. The overall FIS value indicated no pronounced heterozygote deficiency, while FST=0.018 indicated a low level of genetic differentiation among the populations. A total of 29 private alleles were identified across the three populations. FCA and STRUCTURE analyses revealed weak genetic substructure among the populations; in the STRUCTURE analysis, K=3 was identified as the most likely model, with shared genetic components and Admixture observed in all populations. The results indicate that a high level of genetic diversity and a shared genetic background are maintained in the studied Adai horse populations, while local genetic characteristics have also developed. These findings may be used to support the conservation of Adai horse genetic resources, monitor genetic diversity within populations, and facilitate scientifically informed breeding programs.