In this study, complete nucleotide as well as derived amino acid sequence characterization of water buffalo (Bubalus bubalis) kappa-casein gene has been presented. Kappa-casein cDNA clones were identified and isolated from a buffalo lactating mammary gland cDNA library. Sequence analysis of kappa-casein cDNA revealed 850 nucleotides with an open reading frame (ORF) of 573 nucleotides, encoding mature peptide of 169 amino acids. The 5' untranslated region (UTR) comprised 71 nucleotides, while 3' UTR was of 206 nucleotides. A total of 11 nucleotide and seven amino acid changes were observed in, buffalo (Bubalus bubalis) as compared to cattle (Bos taurus), sheep (Ovis aries) and goat (Capra hircus). Among these nucleotide changes, eight were unique in buffalo as they were fully conserved in cattle, sheep and goat. Majority of the nucleotide changes and all the amino acid changes; 14 (Asp-Glu), 19(Asp/Ser-Asn), 96(Ala-Thr), 126(Ala-Val), 128(Ala/Gly-Val), 156(Ala/Pro-Val) and 168(Ala/Glu-Val) were limited to exon IV. Three glycosylation sites, Thr 131, Thr 133 and Thr 142 reported in cattle and goat kappa-casein gene were also conserved in buffalo, however, in sheep Thr 142 was replaced by Ala. Chymosin hydrolysis site, between amino acids Phe 105 and Met 106, important for rennet coagulation process, were found to be conserved across four bovid species. Buffalo kappa-casein with the presence of amino acids Thr 136 and Ala 148 seems to be an intermediate of "A" and "B" variants of cattle. Comparison with other livestock species revealed buffalo kappa-casein sharing maximum nucleotide (95.5%) and amino acid (92.6%) similarity with cattle, whereas with pig it showed least sequence similarity of 76.0% and 53.2%, respectively. Phylogenetic analysis based on both nucleotide and amino acid sequence indicated buffalo kappa-casein grouping with cattle, while sheep and goat forming a separate cluster close to them. The non-ruminant species viz. camel, horse and pig were distantly placed, in separate lineages.

The present study was aimed to identify single-nucleotide polymorphic (SNP) sites in coding regions of CXCR2 gene in Vrindavani cattle. A total of 95 animals were screened for CXCR2 gene locus. Single-strand conformation polymorphism (SSCP) analysis revealed polymorphic patterns, and a total of five distinct patterns were observed in the exon 2 of CXCR2 gene. Sequence analysis of different SSCP variants revealed the presence of five novel SNP at A214G, T340C, G344A, C856T and G1027A. No association of mastitis incidence was detected with different patterns of SSCP for both amplicons of CXCR2 exon 2.

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The exon 2-3 region of bovine major histocompatibility complex (MHC) class I BoLa-A gene was investigated for polymorphisms in three breeds of cattle originated in the Indian subcontinent namely Sahiwal, Tharparkar, Hariana, as well as crossbred (Bos taurus x Bos indicus) cattle and Jersey, the exotic breed (Bos taurus). The PCR amplified fragment of 714 bp showed distinct DdeI-, TaqI-and HinfI-RFLP patterns, thus confirming a higher degree of polymorphism in this region. To our knowledge this is the first report of HinfI restriction patterns for BoLa-A exon 2-3. The sequencing results revealed a number of nucleotide substitutions in this region, which resulted in amino acid changes. The present investigation confirmed that MHC class I BoLa-A exon 2-3 is highly polymorphic in cattle.

Biological diversity, the variability of life on earth, exists in the form of different species and breeds within the animal kingdom. This diversity is created in the process of molecular/biochemical/metabolic reactions, and acts as a critical measure of adaptation in changing climatic conditions. Indigenous breeds have adapted to climatic variations since time immemorial, and hence have acquired unique traits that make them suitable in given agroclimatic zones; for example, the Indian cattle breeds, Tharparkar and Sahiwal, are heat and tick resistant. Similar cases have also been observed worldwide in Asia, Africa, Europe, Latin America, North America and the south-west Pacific region, having a total of 1144, 1300, 345, 104 and 108 breeds of major livestock species, respectively. Native breeds, namely N'Dama cattle, Red Massai sheep, etc., have developed trypanosomiasis resistance and gastrointestinal nematode tolerance by continuous natural selection. The overwhelming majority of indigenous livestock around the world are bred locally and kept by small-scale livestock keepers; hence, there is a need to promote local indigenous livestock species, as they represent a genetic resource that is relatively resilient to climate variability.