Gene Conversion Maintains Nonfunctional Transposable Elements in an Obligate Mutualistic Endosymbiont

作者：Cordaux Richard^*

来源：Molecular Biology and Evolution, 2009, 26(8): 1679-1682.

DOI：10.1093/molbev/msp093

• gene conversion
• transposable element
• insertion sequence
• reductive evolution
• endosymbiont
• Wolbachia

Long-term bacterial endosymbionts typically exhibit reduced genomes, lack genes encoding recombination functions and transposable elements, such as insertion sequences (ISs). In sharp contrast, I found that ISs constitute 2.4% of the genome of the obligate mutualistic endosymbiont Wolbachia wBm. Although no IS copy is transpositionally functional, I show that ISs persist in wBm because of frequent recombinational gene conversion (GC) homogenizing homologous IS sequences. These results not only indicate that there exists a functional recombination molecular machinery in wBm, but they also suggest that, by slowing down the rate of IS degradation and loss, GC may represent a major force influencing reductive evolution in wBm.

• 出版日期2009-8