|
Hokkaido University Collection of Scholarly and Academic Papers >
Graduate School of Agriculture / Faculty of Agriculture >
Peer-reviewed Journal Articles, etc >
Changes in base composition bias of nuclear and mitochondrial genes in lice (Insecta: Psocodea).
| Title: | Changes in base composition bias of nuclear and mitochondrial genes in lice (Insecta: Psocodea). |
| Authors: | Yoshizawa, Kazunori Browse this author →KAKEN DB | | Johnson, Kevin P Browse this author |
| Keywords: | molecular evolution | | GC content | | relaxed selection | | slightly deleterious mutation |
| Issue Date: | Dec-2013 |
| Publisher: | Springer |
| Journal Title: | Genetica |
| Volume: | 141 |
| Issue: | 10-12 |
| Start Page: | 491 |
| End Page: | 499 |
| Publisher DOI: | 10.1007/s10709-013-9748-z |
| PMID: | 24233690 |
| Abstract: | While it is well known that changes in the general processes of molecular evolution have occurred on a variety of timescales, the mechanisms underlying these changes are less well understood. Parasitic lice ("Phthiraptera") and their close relatives (infraorder Nanopsocetae of the insect order Psocodea) are a group of insects well known for their unusual features of molecular evolution. We examined changes in base composition across parasitic lice and bark lice. We identified substantial differences in percent GC content between the clade comprising parasitic lice plus closely related bark lice (=Nanopsocetae) versus all other bark lice. These changes occurred for both nuclear and mitochondrial protein coding and ribosomal RNA genes, often in the same direction. To evaluate whether correlations in base composition change also occurred within lineages, we used phylogenetically controlled comparisons, and in this case few significant correlations were identified. Examining more constrained sites (first/second codon positions and rRNA) revealed that, in comparison to the other bark lice, the GC content of parasitic lice and close relatives tended towards 50 % either up from less than 50 % GC or down from greater than 50 % GC. In contrast, less constrained sites (third codon positions) in both nuclear and mitochondrial genes showed less of a consistent change of base composition in parasitic lice and very close relatives. We conclude that relaxed selection on this group of insects is a potential explanation of the change in base composition for both mitochondrial and nuclear genes, which could lead to nucleotide frequencies closer to random expectation (i.e., 50 % GC) in the absence of any mutation bias. Evidence suggests this relaxed selection arose once in the non-parasitic common ancestor of Phthiraptera + Nanopsocetae and is not directly related to the evolution of the parasitism in lice. |
| Rights: | The final publication is available at link.springer.com |
| Type: | article (author version) |
| URI: | http://hdl.handle.net/2115/57601 |
| Appears in Collections: | 農学院・農学研究院 (Graduate School of Agriculture / Faculty of Agriculture) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
|
Submitter: 吉澤 和徳
|
