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Prospects of high throughput technology in animal genetics makes easy to investigate hidden genetic variation in farm animal?s genetic resources. However, many SNPs technologies are currently practicing in animal genetics. In this study, we investigated genome wide SNPs variations and its distribution across the indigenous cattle population in Pakistan using Illumina Bovine HD (777K) SNPs bead chip. A total of 136 individuals from ten different breeds were genotyped and after filtration 500, 939 SNPs markers were used for further analysis. The mean minor allele frequency (MAF) was 0.23, 0.20, 0.22, 0.22, 0.20, 0.18, 0.20, 0.22, 0.21 and 0.18 observed for Achi, Bhagnari, Cholistani, Dhanni, Dajal, Kankraj, Lohani, Red sindi, Sahiwal and Tharparkar cattle, respectively. Significant difference (P0.05) within breeds and remaining 36% were considered as monomorphic markers. Average observed (Ho) and expected (HE) heterozygosity values 0.662 and 0.640 were estimated among these breeds. In conclusion, this preliminary study results revealed that these SNPs variation level could potentially be used for genetic characterization of zebu cattle breeds and could also be used to estimate genetic potential of these cattle breeds for livestock improvement in country.

The bovine high density SNPs genotyping array has a wide range of applications including detection of selection signatures, identification of copy number variants (CNVs), genome wide association studies, and dendrogram relationships. This array can also be used to improve the accuracy of genomic predictions for low heritable traits viz. reproductive traits. The effectiveness of this array for genomic selection mainly depends on polymorphism level. In this study, we used 136 individuals from ten different Pakistani cattle breeds, include Achi (18), Bhagnari (14), Cholistani (13), Dajal (10), Dhanni (10), Kankraj (12), Lohani (19), Red Sindhi (13), Sahiwal (14), and Tharparkar (13) using high density SNPs genotyping and this array contained approximately 777, 962 SNPs. The results of this study revealed that approximately 500, 939 SNPs were found polymorphic in these breeds. The results indicate that high density SNPs bead chip would offer an informative genotyping platform for quantitative trait loci (QTL) mapping in indigenous Pakistani cattle breeds. Keywords: Copy number variants; Genotyping; Polymorphism; Quantitative trait loci; SNPs http://dx.doi.org/10.19045/bspab.2018.70026

The linkage disequilibrium (LD) is an important tool to study quantitative trait locus (QTL) mapping and genetic selection. In this study, we identified the extent of linkage disequilibrium (LD) in Sahiwal (n = 14) cattle using the bovine high density single-nucleotide polymorphisms (SNPs) BeadChip. After data filtering, 500,968 SNPs comprising 2518.1 Mb of the genome, were used for the LD estimation. The minior allele frequency (MAF) was 0.21 in a substantial proportion of SNPs and mean distance between adjacent markers was 4.77 ± 2.83 kb. The overall mean LD between adjacent markers was 0.18 (r 2 ) and 0.55 (|D'|), respectively. The LD (r 2 ) values reduced with the increase in distance between adjacent markers from 1 kb (0.35) to 100 kb (0.12) and |D'| specified distinct decay of the LD. Chromosomes 1, 27, 28 and 29 presented the LD at some distance between markers. The extent of LD was higher, except these four chromosomes, for markers separated by 20 kb. At < 3 kb distance, the upper value of the linkage disequilibrium (LD) was observed at 0.30. High level of the linkage disequilibrium (LD) between markers was observed at high minor allele frequency (MAF) threshold (0.15), at the short distance between markers. The results of this study revealed that the Bovine high density SNPs BeadChip will be informative for the estimation of breeding value in Sahiwal cattle. Keywords: Breeding value, linkage disequilibrium, minor allele frequency, molecular marker