Variation and evolution of class I Mhc in sexual and parthenogenetic geckos
| Autor: | Ted J. Case, Britta Becker, Ray R. Radtkey, Roy Riblet, Robert D. Miller |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
Sequence analysis
Lineage (evolution) Outbreeding depression Molecular Sequence Data Parthenogenesis Lepidodactylus Major histocompatibility complex General Biochemistry Genetics and Molecular Biology Evolution Molecular biology.animal MHC class I Animals Humans Amino Acid Sequence General Environmental Science Genetics General Immunology and Microbiology biology Histocompatibility Antigens Class I Vertebrate Lizards General Medicine biology.organism_classification Antigenic Variation biology.protein General Agricultural and Biological Sciences Sequence Alignment |
| Zdroj: | Proceedings. Biological sciences. 263(1373) |
| ISSN: | 0962-8452 |
| Popis: | We present the first Mhc class I sequences in geckos. We compared Mhc variation in gekkonid species that reproduce sexually ( Hemidactylus frenatus, Lepidodactylus aureolineatus, L . moestus, L . sp. Arno, L . sp. Takapoto) to others reproducing parthenogenetically ( H. garnotii, L. lugubris ). These comparisons include the known maternal ( L. moestus ) and paternal ( L . sp. Arno) ancestors of the asexual L. lugubris . Sequences similar to other vertebrate species were obtained from both nuclear and cDNA templates indicating that these sequences are derived from expressed class I Mhc loci. Southern blot analysis using gecko class I probes, revealed that parthenogenetic clonal lineages of independent evolutionary origin have no within-clone band variation at class I loci and that no detectable recombination between restriction sites had taken place. Variability in the sexual species was similar to mammalian taxa, i. e. class I genes are highly variable in outbreeding sexual populations. Sequence analysis of the alpha-2 domain of class I genes identified point mutations in a clonal lineage of L. lugubris which led to amino acid substitutions. Potential transspecific allelic lineages were also observed. The persistence of asexual lineages with little or no class I diversification over thousands of generations seems to argue against strong selection for Mhc multi-allelism caused by pathogen-Mhc allele specificity. On the other hand, the high level of heterozygosity in the parthenogenetic species (a consequence of their hybrid origin) may provide clonal lineages with adequate antigen presenting diversity to survive and compete with sexual relatives. |
| Databáze: | OpenAIRE |
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