Nucleotide polymorphisms in the bovine lymphotoxin A gene and their distribution among Bos indicus zebu cattle breeds.

The present study was undertaken to characterize the genetic variation present in lymphoxin A gene (LTA gene) encoding for the lymphotoxin A protein also known as tumor necrosis factor beta, a cytokine produced by lymphocytes, known to be cytotoxic for a wide range of tumor cells both in vitro and in vivo, and, which is essential for normal immunological development; in 40 animals of 5 diverse Bos indicus Indian zebu cattle breeds. These breeds survive under the harsh and tough tropical climatic conditions of various parts of the Indian subcontinent. The LTA gene in the present study was observed to contain 33 SNPs and 3 small insertion/deletion polymorphisms. Four SNPs occurred in the coding regions of the gene viz. g.1327A>G and g.1400C>T in exon 2 and g.1840C>T and g.1942C>T in exon 3, of which the SNP g.1327A>G in exon 2 resulted in a non-synonymous amino acid change G38D. This amino acid change was however predicted not be affecting the protein function in any manner. The gene contained putative transcription factor binding sites for the c-Re1 and for Pax-4 transcription factors. A putative promoter region was also predicted on the reverse DNA strand from position 894 to 644. Several repeat elements and microsatellite repeats were detected to be occurring across the 3.2kb LTA gene sequence. The study showed the occurrence of 40 genotypes and 48 most probable haplotypes. The genotypes at the observed SNP positions in the LTA gene were in near Hardy-Weinberg equilibrium. A negative Tajima's D value that was not significant statistically at P>0.10 indicated that the neutral mutation hypothesis could not be excluded. The genetic variations observed in the LTA gene in the present study have not been reported earlier and these could possibly be used as molecular markers for further studies involving association of the gene variability with disease resistance/tolerance traits.

Genetic polymorphisms in the bovine toll-like receptor 4 (TLR4) and monocyte chemo attractant protein-1(CCL2) genes: SNPs distribution analysis in Bos indicus Sahiwal cattle breed.

Toll-like receptor 4 gene (TLR4) that recognizes the Gram negative bacterial ligand LPS was sequenced in the Bos indicus Sahiwal cattle breed. Ninety four single nucleotide polymorphisms (SNPs) were detected within 10.8 kb gene region. Seventeen of the SNPs were in the coding regions and the one at position 9589(A > G) in exon3 resulted in an amino acid change from Valine to Isoleucine. These SNPs led to generation of 27 TLR4 gene haplotypes. All the Sahiwal animals studied presently showed the occurrence of the genotype CC at gene position 9662, which codes for the amino acid threonine at position 674 of the TLR4 protein, and which had been reported to be associated with lower somatic cell score and, therefore, a lower susceptibility to mastitis, in Taurus cattle. This nucleotide configuration of the Toll-like receptor 4 gene of the Bos indicus Sahiwal cattle breed could possibly indicate toward a lower susceptibility to mastitis in the Sahiwal animals. Monocyte chemo-attractant protein-1 (CCL2) gene encoding for small inducible cytokine A2 that belongs to the CC chemokine family was also sequence characterized in these Sahiwal animals. The CCL2 gene was observed to have 12 polymorphic sites in 3.3 kb region of which one SNP at position 2500 (A > G) in exon 3 resulted in amino acid change from Valine to Isoleucine at position 46 of the mature CCL2 peptide. Seventeen haplotypes of the CCL2 gene were predicted corresponding to 12 genotypes detected.

The major histocompatibility complex in bovines: a review.

Productivity in dairy cattle and buffaloes depends on the genetic factors governing the production of milk and milk constituents as well as genetic factors controlling disease resistance or susceptibility. The immune system is the adaptive defense system that has evolved in vertebrates to protect them from invading pathogens and also carcinomas. It is remarkable in the sense that it is able to generate an enormous variety of cells and biomolecules which interact with each other in numerous ways to form a complex network that helps to recognize, counteract, and eliminate the apparently limitless number of foreign invading pathogens/molecules. The major histocompatibility complex which is found to occur in all mammalian species plays a central role in the development of the immune system. It is an important candidate gene involved in susceptibility/resistance to various diseases. It is associated with intercellular recognition and with self/nonself discrimination. It plays major role in determining whether transplanted tissue will be accepted as self or rejected as foreign.