Sex chromosomes and autosomes often differ in their relative rates of evolution, with sex chromosomes generally accumulating changes more rapidly (faster-X evolution). Transposable elements (TEs) make up a significant portion of eukaryotic genomes and are some of the most rapidly evolving genetic elements. We compared relative rates of insertion on the X and autosomes for 78 families found in Drosophila melanogaster. The average X/A ratio for these TE families was 1.11, similar to the mean dS X/A ratio, indicating no male-bias in mutation rate or TE insertion. The major mode of the distribution was ~0.8, indicating stronger purifying selection on the X chromosome for most TEs. We found no effect on X/A from sex-specific TE expression, but TEs with male-specific piRNA had an average X/A ratio of 0.62. We also found that TEs with very high X/A ratios (top 5%) had X chromosome insertions in areas of relative low recombination.
| Identifer | oai:union.ndltd.org:MSSTATE/oai:scholarsjunction.msstate.edu:td-4778 |
| Date | 12 August 2016 |
| Creators | Savell, Christopher D |
| Publisher | Scholars Junction |
| Source Sets | Mississippi State University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Theses and Dissertations |
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