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Evolution of Mhc-DRB introns: Implications for the origin of primates
- Source :
- Journal of Molecular Evolution. 48:663-674
- Publication Year :
- 1999
- Publisher :
- Springer Science and Business Media LLC, 1999.
-
Abstract
- Introns are generally believed to evolve too rapidly and too erratically to be of much use in phylogenetic reconstructions. Few phylogenetically informative intron sequences are available, however, to ascertain the validity of this supposition. In the present study the supposition was tested on the example of the mammalian class II major histocompatibility complex (Mhc) genes of the DRB family. Since the Mhc genes evolve under balancing selection and are believed to recombine or rearrange frequently, the evolution of their introns could be expected to be particularly rapid and subject to scrambling. Sequences of intron 4 and 5 DRB genes were obtained from polymerase chain reaction-amplified fragments of genomic DNA from representatives of six eutherian orders—Primates, Scandentia, Chiroptera, Dermoptera, Lagomorpha, and Insectivora. Although short stretches of the introns have indeed proved to be unalignable, the bulk of the intron sequences from all six orders, spanning >85 million years (my) of evolution, could be aligned and used in a study of the tempo and mode of intron evolution. The analysis has revealed the Mhc introns to evolve at a rate similar to that of other genes and of synonymous sites of non-Mhc genes. No evidence of homogenization or large-scale scrambling of the intron sequences could be found. The Mhc introns apparently evolve largely by point mutations and insertions/deletions. The phylogenetic signals contained in the intron sequences could be used to identify Scandentia as the sister group of Primates, to support the existence of the Archonta superorder, and to confirm the monophyly of the Chiroptera.
- Subjects :
- Primates
HLA-DR beta-Chains
Molecular Sequence Data
Biology
Archonta
Evolution, Molecular
Phylogenetics
Genetics
Animals
Humans
Molecular Biology
Gene
Phylogeny
Ecology, Evolution, Behavior and Systematics
Base Sequence
Phylogenetic tree
Histocompatibility Antigens Class II
Intron
HLA-DR Antigens
biology.organism_classification
Introns
HLA-DRB5 Chains
Scandentia
genomic DNA
Sister group
HLA-DRB1 Chains
Subjects
Details
- ISSN :
- 00222844
- Volume :
- 48
- Database :
- OpenAIRE
- Journal :
- Journal of Molecular Evolution
- Accession number :
- edsair.doi.dedup.....eb53dfe2cfb01b994040e761eb725f2d
- Full Text :
- https://doi.org/10.1007/pl00006510