The present study was undertaken with the objectives of molecular characterization and detection of genetic polymorphisms in the HSPB6 gene of Sahiwal cattle. A total of 100 Sahiwal cattle maintained at LRC, NDRI, Karnal (Haryana) were included in the study. HSPB6 gene has been mapped on Bos taurus autosome 18 (BTA 18) and spans nearly 2620 bp comprising 3 exons and 2 introns. Four sets of forward and reverse gene-specific oligonucleotide primers of HSPB6 gene were designed using Primer3 software and amplicon size of 529 bp, 460 bp, 670 bp and 502 bp were ascertained. On the basis of comparative sequence analysis, total three polymorphic loci (SNPs) were detected at locus G436A, A2152G and A2417T in HSPB6 gene as compare to Bos taurus (NCBI GenBank AC_000175.1). Out of these three SNPs, two (A2152G & A2417T) were found in 3´-UTR region and third one (G436A) was detected in intronic region 1. However, monomorphic pattern was found in exon 2 of HSPB6 gene in Sahiwal cattle. Further research need be directed to find out the association of allelic variants in major heat shock protein genes to establish markers for the future genetic improvement of livestock through marker assisted selection. 

Molecular characterization and polymorphism detection in  HSPB6 gene in Sahiwal cattle

<div>Background: Selection process for milk performance traits has left remarkable selection signatures in the genome and their identification can guide to utilize under genomic breeding programs for improving productivity in dairy cattle. 
 
Methods: This study utilizes genotype data of Sahiwal (19), Tharparkar (17) and Gir (16) to identify selection signatures in the genomes of Sahiwal-Gir (SW-GR), Sahiwal-Tharparkar (SW-TP) and Tharparkar-Gir (TP-GR) breed pairs by using FST approaches. The highest FST peaks (FST &gt;0.25) were considered as selection signature region. The functional genes underlying signature regions controlling milk performance traits were also annotated. 
 
Result: We identified 41, 29 and 60 selection signatures exhibiting footprints of positive selection among SW-GR, SW-TP and TP-GR breed pairs, respectively. The selection signals controlling milk performance traits were detected as ACADL, SLC26A2, PLCB1, SYT9 genes mapped on chromosome 2, 7, 13 and 15, respectively for SW-GR breed pair. Selection signature regions in the genome of SW-TP breed revealed genes ATPAF1, LEF1, PPARGC1B, EIF6 and ACSS3 for milk production. Furthermore, PLA2R1, SCP2, ATPAF1, CACNA2D1, LEF1 and SUMF1 genes were identified in TP-GR breed pair controlling metabolism and morphogenesis of mammary gland. Moreover, HSPB6, LTBP1, SLIT3, FSHR and ASIP genes were also found in association with thermo-tolerance, disease resistance, immunity, reproduction and coat colour in our indigenous dairy cattle breeds.</div>

Molecular characterization and polymorphism detection in HSPB6 gene in Sahiwal cattle

Identification of Selection Signatures for Milk Performance Traits among Indigenous Dairy Cattle Breeds using High Density Genomic Information