A review on genetic characterization of indigenous cattle breeds

Indian cattle breeds are diverse and well adapted to 15 different agro-climatic regions. Assessment of genetic diversity and population structure is highly essential for conservation and utilization of indigenous cattle genetic resources. Genome-wide Single Nucleotide Polymorphism (SNP) information is widely used for genetic characterization among the cattle population. Average heterozygosity was estimated as 0.35 among 11 diverse dairy, dual and draft type Indian cattle breeds, which provided scope for their genetic improvement through selection. Indian indigenous breeds are genetically distinct from exotic dairy cattle breeds, whereas a substantially shorter genetic distance was observed among Indian breeds. This supports the evolutionary theory of Indicine zebu cattle and their divergence from Taurine cattle. Principal component analysis revealed that the draft/dual breeds i.e. Vechur, Kangayam and Ongole are clustered separately from dairy type breeds. Population structure analysis identified the presence of highest level of admixture in Vechur cattle, due to which its population is sizably declining. Genetic characterization is essential to preserve the genomic variability which can further be used for genetic improvement of performance traits in a population. Therefore, this review suggests the genetic characterization of indigenous cattle population for formulating conservation policies in order to prevent our native population from extinction.