Genetic Structure in a Montane Mayfly Baetis Bicaudatus ( Ephemeroptera: Baetidae), from the Rocky Mountains, Colorado
Description
- Populations of a number of sub-tropical stream insect species have been found to show unexpected patterns of genetic variation, with more differences between samples from the same stream than between whole streams or between subcatchments. Many samples also showed deviations from Hardy–Weinberg proportions. It has been proposed that these patterns result from limited numbers of matings contributing to a given stream reach, because adults emerge throughout the year, and low levels of larval drift between reaches. These patterns may be less likely in a northern hemisphere montane species with synchronous emergence of adults and high levels of drift. We tested the hypothesis that patterns of genetic variation in a montane mayfly from the Rocky Mountains, Colorado, would reflect a pattern of 'isolation by distance' with samples from the same creek being more similar than samples from different creeks and that deviations from Hardy–Weinberg proportions would be minimal. 2. Based on allozyme variation, the hypothesis of minimal deviations from Hardy–Weinberg proportions was not supported and there was no evidence of isolation by distance. Nevertheless the levels of differentiation among samples from within the same stream were less than those reported for most subtropical species. 3. Results from analysis of a fragment of the cytochrome oxidase gene (subunit 1) revealed contrasting patterns. The levels of genetic differentiation were an order of magnitude higher between streams than among samples within streams. In addition, although there was no significant isolation by distance effect overall, a nested clade analysis provided evidence for restricted gene flow with isolation by distance for some clades. 4. We suggest that these contrasting results may reflect the differences in male and female dispersal patterns. While differentiation at nuclear gene markers (allozymes) give information about both male and female dispersal, mitochondrial DNA markers reflect only female dispersal. We suggest that in this species, female dispersal may be more restricted, perhaps mostly along stream channels, whereas male dispersal is more widespread. An alternative explanation for the different results is the different evolutionary rates of the mitochondrial and nuclear markers.
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| ID Code: | 10077 |
|---|---|
| Item Type: | Contribution to Journal (Journal Article) |
| Refereed: | Yes |
| Measurements or Duration: | 14 pages |
| DOI: | 10.1046/j.1365-2427.2003.01150.x |
| ISSN: | 0046-5070 |
| Pure ID: | 34129501 |
| Divisions: | Past > QUT Faculties & Divisions > Faculty of Science and Technology Past > QUT Faculties & Divisions > Science & Engineering Faculty Current > Research Centres > Australian Research Centre for Aerospace Automation |
| Copyright Owner: | Consult author(s) regarding copyright matters |
| Copyright Statement: | This work is covered by copyright. Unless the document is being made available under a Creative Commons Licence, you must assume that re-use is limited to personal use and that permission from the copyright owner must be obtained for all other uses. If the document is available under a Creative Commons License (or other specified license) then refer to the Licence for details of permitted re-use. It is a condition of access that users recognise and abide by the legal requirements associated with these rights. If you believe that this work infringes copyright please provide details by email to qut.copyright@qut.edu.au |
| Deposited On: | 11 Oct 2007 00:00 |
| Last Modified: | 03 Mar 2024 16:39 |
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