Linked Life Data

10331274

Source:http://linkedlifedata.com/resource/pubmed/id/10331274

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1999-6-22
pubmed:databankReference
pubmed:abstractText
The major histocompatibility complex (Mhc) of the ring-necked pheasant contains two polymorphic Mhc class II B genes. We show here, by screening of a cDNA library and RT-PCR from RNA, that both of these loci, Phco-DAB1 and Phco-DAB2, normally are transcribed in the spleen. They differ mainly in the 3' untranslated (UT) region, with the transcript lengths, not including the poly(A) tails, being 1,100 nt for DAB1 and 955 nt for DAB2. These two loci are orthologous to the B-LBI and B-LBII loci of the domestic chicken, respectively. DAB1 and DAB2 therefore seem to have evolved from a duplication before the split of the evolutionary lineages leading to the pheasant and the domestic chicken ca. 20 MYA. This is the first report of an orthologous relationship between avian Mhc genes. Yet, the third exons of DAB1 and DAB2 were identical in all available sequences and differed at 10 positions from the exon 3 sequences of B-LBI/B-LBII. The species-specific exon 3 suggests that DAB1 and DAB2 are subject to concerted evolution, i.e., interlocus genetic exchange. The exon 2 sequences show characteristic polymorphism, with hypervariable segments occurring in different combinations in different alleles. Given the divergence in the 3'UT region, the finding of the same exon 2 sequence at both the DAB1 and the DAB2 loci in one of the pheasant haplotypes also suggests that interlocus genetic exchange does occur. Accordingly, the exon 2 sequences tended to cluster irrespective of locus in the phylogenetic analyses. Genetic exchange simultaneously involving both exon 2 and exon 3 may be facilitated by the short length of the intervening intron (< 100 bp) in pheasants and domestic chickens compared with, e.g., humans (about 3 kb).
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0737-4038
pubmed:author
pubmed:issnType
Print
pubmed:volume
16
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
479-90
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:10331274-3' Untranslated Regions, pubmed-meshheading:10331274-Alleles, pubmed-meshheading:10331274-Amino Acid Sequence, pubmed-meshheading:10331274-Animals, pubmed-meshheading:10331274-Base Sequence, pubmed-meshheading:10331274-Birds, pubmed-meshheading:10331274-Chickens, pubmed-meshheading:10331274-Cloning, Molecular, pubmed-meshheading:10331274-DNA, Complementary, pubmed-meshheading:10331274-DNA Primers, pubmed-meshheading:10331274-Evolution, Molecular, pubmed-meshheading:10331274-Genes, MHC Class II, pubmed-meshheading:10331274-Heterozygote, pubmed-meshheading:10331274-Homozygote, pubmed-meshheading:10331274-Humans, pubmed-meshheading:10331274-Molecular Sequence Data, pubmed-meshheading:10331274-Phylogeny, pubmed-meshheading:10331274-Sequence Homology, Amino Acid, pubmed-meshheading:10331274-Sequence Homology, Nucleic Acid, pubmed-meshheading:10331274-Species Specificity
pubmed:year
1999
pubmed:articleTitle
Concerted evolution of two Mhc class II B loci in pheasants and domestic chickens.
pubmed:affiliation
Centre National de la Recherche Scientifique, Villejuif, France. hakan.wittzell@teorekol.lu.se
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't