RESUMO
The yak (Bos grunniens), renowned for its adaptability to extreme cold and hypoxic conditions, stands as a remarkable domestic animal crucial for sustaining livelihoods in harsh climates. We conducted a comprehensive analysis of the whole genome sequence data from three distinct Indian yak populations: Arunachali yak (n = 10), Himachali yak (n = 10), and Ladakhi yak (n = 10). The genomic data for Indian yaks were meticulously generated by our laboratory and compared with their Chinese counterpart, the Jinchuan yak (n = 8), for a more nuanced understanding. Our investigation revealed a total of 37,437 runs of homozygosity (ROH) segments in 34 animals representing four distinct yak populations. The Jinchuan yak population exhibited the highest proportion, constituting 80.8 % of total ROHs, predominantly as small segments (<0.1 Mb), accounting for 63 % of the overall ROHs. Further analysis uncovered a significantly higher degree of inbreeding in Chinese yaks compared to their Indian counterparts. The Indian yak populations, in contrast, demonstrated relatively lower and consistent levels of inbreeding. Moreover, we identified ROH hotspots that covered at least 60 % of individuals in our study, indicating their pivotal role in environmental adaptation. A total of five hotspot regions were detected, housing genes such as ENSBGRG00000015023 (WNT2), YIPF4, SPAST, TLN2, and DSG4. These genes are associated with traits including hair follicle initiation, nutrient stress response, microtubule assembly, development of cardiac muscle, hair follicle, and coat color. This observation strongly suggests that there is substantial selection acting on these genes, emphasizing their important role in environmental adaptation among yak populations.
RESUMO
Cattle are losing maximum breeds among the world's livestock. Genetic variability data is essentially required for conservation decision-making. Thutho is a recently registered Indian cattle breed (INDIA_CATTLE_1400_THUTHO_03047) from the northeast region (NE), a biodiversity hotspot. Genetic diversity in the Thutho population and its differentiation from the only other cattle breed of NE (Siri) and cattle (Bachaur) of the neighboring region was established using highly polymorphic, FAO-recommended microsatellite markers. Numerous alleles (253) were detected across the 25 loci. The mean observed and expected numbers of alleles in the population were 10.12 ± 0.5 and 4.5 ± 0.37, respectively. The observed heterozygosity (0.67 ± 0.04) was lower than the expected heterozygosity (0.73 ± 0.03) which indicated a departure from the Hardy-Weinberg equilibrium. A positive FIS value (0.097) confirmed the heterozygote deficiency in the Thutho population. Genetic distance, phylogenetic relationships, differentiation parameters, population assignment, and Bayesian analysis explicitly ascertained the unique genetic identity of the Thutho cattle. The population did not suffer any bottlenecks in the past. Thutho has minimum diversity among the three populations; hence, its scientific management needs to be initiated immediately. Interestingly, genetic variation is enough for formulating breeding programs for managing, improving, and conserving this precious indigenous cattle germplasm.
