Scienski Kathy, Fay Justin C, Conant Gavin C
Division of Animal Sciences, University of Missouri, Columbia Present address: Genetics Graduate Program, Texas A&M University, College Station, TX.
Department of Genetics, Washington University Center for Genome Sciences and Systems Biology, Washington University
Genome Biol Evol. 2015 Nov 11;7(12):3249-58. doi: 10.1093/gbe/evv216.
We find evidence for interlocus gene conversion in five duplicated histone genes from six yeast species. The sequences of these duplicated genes, surviving from the ancient genome duplication, show phylogenetic patterns inconsistent with the well-resolved orthology relationships inferred from a likelihood model of gene loss after the genome duplication. Instead, these paralogous genes are more closely related to each other than any is to its nearest ortholog. In addition to simulations supporting gene conversion, we also present evidence for elevated rates of radical amino acid substitutions along the branches implicated in the conversion events. As these patterns are similar to those seen in ribosomal proteins that have undergone gene conversion, we speculate that in cases where duplicated genes code for proteins that are a part of tightly interacting complexes, selection may favor the fixation of gene conversion events in order to maintain high protein identities between duplicated copies.
我们在来自六个酵母物种的五个重复组蛋白基因中发现了基因座间基因转换的证据。这些从古基因组复制中留存下来的重复基因序列，所呈现的系统发育模式与从基因组复制后基因丢失的似然模型推断出的明确直系同源关系不一致。相反，这些旁系同源基因彼此之间的关系比任何一个与它最接近的直系同源基因的关系都更为密切。除了支持基因转换的模拟结果外，我们还提供了证据表明，在涉及转换事件的分支上，激进氨基酸替换的速率有所提高。由于这些模式与在经历了基因转换的核糖体蛋白中所观察到的模式相似，我们推测，在重复基因编码紧密相互作用复合物一部分的蛋白质的情况下，选择可能有利于基因转换事件的固定，以便在重复拷贝之间维持高蛋白质同一性。
