![]() ![]() In general, they occupy distinct geographic and climatic locations worldwide. The domestication of wild aurochs ( Bos primigenous) in two distinct locations, in the Middle East (~ 10,000 years ago) and the Indian subcontinent (~ 8000), resulted in the separate evolution of two cattle lineages and in divergences between the genomes of taurine ( Bos primigenous taurus) and indicine ( Bos primigenous indicus) cattle. Thus, HELB likely contributed to the adaptation of tropical cattle to their harsh environment. HELB is involved in the response to DNA damage including exposure to ultra-violet light and is associated with reproductive traits and yearling weight in tropical cattle. We identified a 430-kb selective sweep in Asian indicine cattle located on chromosome 5, which carries SNPs that are fixed in indicine populations and located in the coding sequences of the HELB gene. Major genomic sequence differences between Bos taurus and Bos indicus are enriched for promoter and coding regions. Based on in-house genome sequences, we proved that mutations in HELB segregate independently of the copy number variation HMGA2-CNV, which is located in the same region. By mining information from the 1000 Bull Genomes Project, we found that HELB carries mutations that are specific to indicine cattle but also found in taurine cattle, which are known to have been subject to indicine introgression from breeds, such as N’Dama, Anatolian Red, Marchigiana, Chianina, and Piedmontese. We identified nine single nucleotide polymorphisms (SNPs) in coding regions that are fixed for different alleles between subspecies, eight of which were located within the DNA helicase B ( HELB) gene. At the nucleotide level, sites that show a strong divergence in allele frequency between European taurine and Asian indicine are enriched for the same functional categories. Regions under selection in indicine cattle display significant enrichment for promoters and coding genes. HELB, IRAK3, ENSBTAG00000026993, GRIP1 and part of HMGA2. We identified selective sweeps in beef cattle taurine and indicine populations, including a 430-kb selective sweep on indicine cattle chromosome 5 that is located between 47,670,001 and 48,100,000 bp and spans five genes, i.e. ![]() Next, we studied the impact of divergent selection by exploiting predicted and experimental functional annotation of the bovine genome. In this study, we assessed the impact of artificial selection and environmental adaptation by comparing whole-genome sequences from European taurine and Asian indicine breeds and from African cattle. Distinct domestication events, adaptation to different climatic zones, and divergent selection in productive traits have shaped the genomic differences between taurine and indicine cattle. ![]()
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