Nucleotide sequence variability analysis of Major Histocompatibility Complex Class II DQA1 gene in Nigerian goats

Major Histocompatibility Complex (MHC) molecules loaded with peptides derived from invading pathogens are recognised by the immune system to produce a highly effective and specific response against foreign pathogens. A 310-bp fragment of exon 2 of the MHC Class II DQA1 gene was amplified in 27 animals made up of three major Nigerian goat breeds [West African Dwarf (WAD), Red Sokoto (RS) and Sahel (SH)]. Twenty amino acid polymorphic sites were found in Nigerian goats. Comparison of predicted amino acid residues of DQA1 exon 2 alleles of Nigerian goats with similar alleles from other caprine species revealed considerable congruence in amino acid substitution pattern. A significant positive selection signature was detected at the DQA1 locus of Nigerian goats in that non-synonymous substitutions occurred at a faster rate compared to synonymous substitutions (dN:dS ratio = 1.28 ; Z-Statistics= 1.634; P<0.05). The evolutionary tree constructed using UPGMA, revealed that the southern WAD goat appeared to be more related to the northern RS than SH goat at the DQA1 locus. It will be interesting therefore, for future studies to investigate the association of the genetic variants in DQA1 gene of Nigerian goats with resistance/susceptiblity to diseases in order to conserve these precious animal genetic resources.

Short Communication: New alleles at the BoLA-DQA1 locus in Holstein–Fresian cattle

Kułajaj, D., Pokorska, J., Ormian, M. and Dusza, M. 2015. Short Communication: New alleles at the BoLA-DQA1 locus in Holstein Fresian cattle. Can. J. Anim. Sci. 95: 161–164. The aim of the study was to analyze genetic polymorphism at locus BoLA-DQA1 in Polish Holstein-Friesian cattle, using next generation sequencing technology (Miseq sequencer – Illumina). In the studied cattle population we identified 14 alleles, of which three were determined for the first time (BoLA-DQA1*0106, BoLA-DQA1*3201, BoLA-DQA1*3301). The frequencies of these alleles were respectively: 0.0423, 0.0282, 0.0282. At locus BoLA-DQA1 the highest frequency was found for the BoLA-DQA1*10011 and BoLA-DQA1*0101 alleles and their frequencies were respectively: 0.3592 and 0.2606. The frequencies of other alleles identified in the studied population ranged from 0.0070 to 0.0704. The results obtained in this study indicate that the BoLA-DQA1 locus is highly polymorphic and new alleles are still identifiable.