Diversity and locus specificity of chicken MHC B class I sequences.
The major histocompatibility complex B (MHC B) region in a standard haplotype of Leghorn chickens contains two closely linked class I loci, B-FI and B-FIV. Few sequences of B-FI alleles are available, and therefore alleles of the two loci have not been compared with regard to sequence diversity or locus specificity. Here, we report eight new B-F alpha 1/alpha 2-coding sequences from broiler chicken MHC B haplotypes, and a unique recombinant between the two B-F loci. The new sequences were combined with existing B-F sequences from Leghorn and broiler haplotypes for analysis. On the basis of phylogenetic analysis and conserved sequence motifs, B-F sequences separated into two groups (Groups A and B), corresponding to B-FIV and B-FI locus, respectively. Every broiler haplotype had one B-F sequence in Group A and the second B-F sequence, if it existed, clustered in Group B. Group B (presumptive B-FI locus) sequences identified in broiler haplotypes resembled the human MHC class I HLA-C locus in their distinctive pattern of allelic polymorphism. Compared with B-FIV, B-FI alleles were less polymorphic and possessed a conserved locus-specific motif in the alpha1 helix, but nevertheless demonstrated evidence of diversifying selection. One B-FI alpha 1/alpha 2-coding nucleotide sequence was completely conserved in four different broiler haplotypes, but each allele differed in the exon encoding the alpha 3 domain.
Livant
E J
EJ
Department of Poultry Science Department of Pathobiology, Auburn University, Auburn, AL 36849, USA.
Brigati
J R
JR
Ewald
S J
SJ
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002645:Chickens / Q000235:genetics*; D016000:Cluster Analysis; D017124:Conserved Sequence / Q000235:genetics; D017931:DNA Primers; D005805:Genes, MHC Class I / Q000235:genetics*; D006239:Haplotypes / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D011110:Polymorphism, Genetic; D017422:Sequence Analysis, DNA
D017931:DNA Primers