We studied ectopic gene conversions, i.e., gene conversions between duplicated genes located at different chromosomal positions, in eukaryotic genomes. In the first part we examined the factors affecting ectopic gene conversions in the human genome and compared their characteristics to those observed in other eukaryotic and prokaryotic species. In the second part, we examined the effect that ectopic conversions have on the GC-content of the duplicated genes found in yeast and Arabidopsis genomes.
Using Stanley Sawyer's method implemented in his GENCONV program, we identified and characterized the ectopic gene conversions of the human genome. The human gene families containing 3 or more members contained 483 pairs of converted genes. The average length of conversions is 371+/-752 (+/- standard deviation) nucleotides long with the smallest conversions being 10 nucleotides long and the largest 6011 nucleotides long. Larger gene conversions are found between sequences that are more similar and the frequency of intra-chromosomal gene conversion increases as the distance between genes decreases. Pairs of intra-chromosomal genes sharing the same transcriptional orientation convert more often than intra-chromosomal genes in opposite transcriptional orientation. The excess of conversions in the 3'-end suggest incomplete cDNA molecules are often involved in gene conversions with chromosomal gene copies.
Allelic recombination has previously been shown to increase the GC-content of the sequences of a wide variety of eukaryotic species. Ectopic recombination between clustered tandemly repeated genes has also been shown to increase their GC-content. Here we show that gene conversions between the dispersed genes found in the duplicated regions of the yeast and Arabidopsis genomes also increases their GC-content when these genes are more than 88% similar.
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/27111 |
| Date | January 2006 |
| Creators | Benovoy, David |
| Publisher | University of Ottawa (Canada) |
| Source Sets | Université d’Ottawa |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 59 p. |
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