Scheda di dettaglio – i prodotti della ricerca
| Dato | Valore |
|---|---|
| Title | Evidence for inefficient selection against deleterious mutations in cytochrome oxidase I of asexual bdelloid rotifers |
| Abstract | Evolutionary theory predicts that natural selection should be less efficient in asexually than in sexually reproducing organisms. Obligate asexuals are expected to adapt slowly to changing environments and to accumulate mildly deleterious mutations to their genomes, potentially explaining their typically short evolutionary lifespans. One group of animals that appear to challenge these ideas is the bdelloid rotifers, a large and ancient clade of obligate asexuals. Previous work has found no evidence for inefficient selection against deleterious mutations in protein-coding genes of bdelloids. However, these studies relied mostly on between-species comparisons and were therefore unable to detect mildly deleterious mutations that persist within populations but are removed by selection over longer time periods. Here, we test for inefficient purifying selection acting on the cytochrome oxidase I (cox1) mitochondrial gene in 3 clades of bdelloids. Patterns of variation are compared to those of two facultatively sexual clades: a monogonont rotifer (Brachionus) and a branchiopod crustacean (Daphnia). As predicted due to the strict linkage between mitochondrial and nuclear genomes, bdelloids exhibit higher frequencies of putatively deleterious amino acid polymorphism within populations than the two facultatively sexual clades. While the monophyly and age of bdelloids makes it hard to rule out other explanations for the observed differences, several possible confounding factors, such as differences in effective population size or patterns of codon usage, are shown not to explain the observed differences. We therefore conclude that bdelloid mitochondrial DNA variation does display the signature of inefficient selection expected of obligate asexuals. |
| Source | Molecular biology and evolution 24 (9), pp. 1952–1962 |
| Keywords | bdelloid rotifersasexualadaptationmutationspopulation genetics |
| Journal | Molecular biology and evolution |
| Editor | University of Chicago Press,, Chicago, Ill., Stati Uniti d'America |
| Year | 2007 |
| Type | Articolo in rivista |
| DOI | 10.1093/molbev/msm123 |
| Authors | Barraclough, Timothy G.; Fontaneto, Diego; Ricci, Claudia; Herniou, Elisabeth A. |
| Text | 283708 2007 10.1093/molbev/msm123 ISI Web of Science WOS 000249587200006 bdelloid rotifers asexual adaptation mutations population genetics Evidence for inefficient selection against deleterious mutations in cytochrome oxidase I of asexual bdelloid rotifers Barraclough, Timothy G.; Fontaneto, Diego; Ricci, Claudia; Herniou, Elisabeth A. Imperial College London; Imperial College London; Jodrell Bank Centre for Astrophysics; University of Milan Evolutionary theory predicts that natural selection should be less efficient in asexually than in sexually reproducing organisms. Obligate asexuals are expected to adapt slowly to changing environments and to accumulate mildly deleterious mutations to their genomes, potentially explaining their typically short evolutionary lifespans. One group of animals that appear to challenge these ideas is the bdelloid rotifers, a large and ancient clade of obligate asexuals. Previous work has found no evidence for inefficient selection against deleterious mutations in protein coding genes of bdelloids. However, these studies relied mostly on between species comparisons and were therefore unable to detect mildly deleterious mutations that persist within populations but are removed by selection over longer time periods. Here, we test for inefficient purifying selection acting on the cytochrome oxidase I cox1 mitochondrial gene in 3 clades of bdelloids. Patterns of variation are compared to those of two facultatively sexual clades a monogonont rotifer Brachionus and a branchiopod crustacean Daphnia . As predicted due to the strict linkage between mitochondrial and nuclear genomes, bdelloids exhibit higher frequencies of putatively deleterious amino acid polymorphism within populations than the two facultatively sexual clades. While the monophyly and age of bdelloids makes it hard to rule out other explanations for the observed differences, several possible confounding factors, such as differences in effective population size or patterns of codon usage, are shown not to explain the observed differences. We therefore conclude that bdelloid mitochondrial DNA variation does display the signature of inefficient selection expected of obligate asexuals. 24 Articolo in rivista University of Chicago Press, 0737 4038 Molecular biology and evolution Molecular biology and evolution Mol. biol. evol. Molecular biology and evolution. MBE diego.fontaneto FONTANETO DIEGO |