Polymorphisms within Intron-4 and Exon-4 regions of SPP1 gene and their association with milk traits in Gaolao cattle

Secreted phosphoprotein 1 (SPP1) is an acidic, phosphorylated glycoprotein found in fluids including milk and is involved in development of mammary gland and exhibits impact on milk composition and yield. The aim of study was to reveal SPP1 gene polymorphisms and association with milk traits in Gaolao cattle. Blood was collected from 280 cows and test day milk was recorded. SPP1G1-BsrI locus in intron-IV was polymorphic and frequency of TT genotype was 0.99 and CT was 0.01, respectively. The association of SPP1G1-BsrI polymorphism with milk traits revealed significant difference in Milk yield and SNF% for CT genotype as compared to TT genotype. Sequencing of SPP1G1-BsrI locus-based TT and CT genotypes revealed G-A SNP at 32nd position. The SPP1G5-SSCP locus at exon-4 region was polymorphic with frequency for A pattern as 0.95 and for B patterns as 0.05. The association study, revealed significant differences for SNF% and Lactose% for SPP1G5-SSCP pattern A as compared to pattern B. Direct sequencing of SSCP pattern A and B of SPP1G5-SSCP revealed SNPs A-G at 71st, A-C at 109th and A-C at 208th position and 02 computational SNPs, viz. C-A at 109th position and C-A at 208th position. Identified significant association needs validation in large data sets with records for development of markers for bovine milk traits.