Allele mining in the caprine alpha-lactalbumin (LALBA) gene of native Saudi origin

Abstract

Alpha-lactalbumin (α-LA) is a distinctive whey protein found in bovine milk and the milk of other mammalian species. Its main function in the lactating mammary glands is involved in lactose biosynthesis, which makes it a potential quantitative trait locus. The aim of this study is to determine the incidence of single nucleotide polymorphisms (SNPs) within the exonic and intronic portions of the caprine α-LA gene (LALBA) in native Saudi breeds (Ardi, Habsi and Harri) in relation to utility traits. Blood samples were collected from 300 animals (100 for each breed). Genomic DNA was extracted and a 268 bp fragment of the LALBA gene comprising exon 3 and its flanking area was amplified. Subsequent digestion with MvaI restriction endonuclease resulted in two different banding patterns: αLA A1/αLA A1 and αLA A1/αLA A2, and two allelic forms, i.e. αLA A1 and αLA A2. Nucleotide sequencing of the designated LALBA amplicons was done and, following successful BLAST analysis, the sequences were submitted to GenBank (NCBI Accession No. KM267632, KM267633, KM267634 and KP940442). SNPs were searched within breeds of Saudi origin and homology was sought among caprine, ovine and bovine species. A C > T transition was identified within the fifth nucleotide of the silent α-LA A2 allele. Phylogenetic analysis on the basis of LALBA nucleotide sequence of Saudi goats indicated similarity with evolutionarily related sheep, while the origin of bovine species and deer was located some distance away.

Keywords

• α-LA
• SNPs
• alleles
• nucleotide sequencing
• phylogenetics