ABSTRACT
Major histocompatibility complex class II locus DRB variation was investigated by single-strand conformation polymorphism analysis and sequence analysis in the two subspecies of Pyrenean chamois (Rupicapra pyrenaica) endemic to the Iberian Peninsula. Low levels of genetic variation were detected in both subspecies, with seven different alleles in R. p. pyrenaica and only three in the R. p. parva. After applying the rarefaction method to cope with the differences in sample size, the low allele number of parva was highlighted. The low allelic repertoire of the R. p. parva subspecies is most likely the result of bottlenecks caused by hunting pressure and recent parasitic infections by sarcoptic mange. A phylogenetic analysis of both Pyrenean chamois and DRB alleles from 10 different caprinid species revealed that the chamois alleles form two monophyletic groups. In comparison with other Caprinae DRB sequences, the Rupicapra alleles displayed a species-specific clustering that reflects a large temporal divergence of the chamois from other caprinids, as well as a possible difference in the selective environment for these species.
Subject(s)
HLA-DR Antigens/genetics , Rupicapra/genetics , Amino Acid Sequence , Animals , Evolution, Molecular , Gene Frequency , Genetic Variation , Genetics, Population , Geography , HLA-DRB1 Chains , Molecular Sequence Data , Phylogeny , Polymorphism, Genetic , Polymorphism, Single-Stranded Conformational , Sequence Analysis, DNA , SpainABSTRACT
Primers based on GenBank sequences of the ovine tumour necrosis factor (TNF)-alpha gene were designed to amplify a 273-bp fragment comprising part of the fourth exon and the 3' untranslated region (UTR) of the ovine TNF-alpha gene. Five different single-strand conformational polymorphism (SSCP) patterns were detected in a number of unrelated animals and three different alleles were identified and sequenced. These alleles differed in one deletion and one single nucleotide polymorphism (SNP) and were named TNF*01, TNF*02 and TNF*03. These alleles corresponded to three sequences previously characterized by other groups. In the population analysis, no significant differences were found in the frequencies of the Latxa and Rasa breeds. This is the first description of allelic variation in the ovine TNF-alpha gene.
