State Key Laboratory of Silkworm Genome Biology, Southwest University, Beibei, Chongqing 400715, China.
Genome. 2018 Aug;61(8):587-594. doi: 10.1139/gen-2017-0208. Epub 2018 Jun 29.
Horizontal transposable element transfer (HTT) events have occurred among a large number of species and play important roles in the composition and evolution of eukaryotic genomes. HTTs are also regarded as effective forces in promoting genomic variation and biological innovation. In the present study, HTT events were identified and analyzed in seven sequenced species of Rosales using bioinformatics methods by comparing sequence conservation and K/K value of reverse transcriptase (RT) with 20 conserved genes, estimating the dating of HTTs, and analyzing the phylogenetic relationships. Seven HTT events involving long terminal repeat (LTR) retrotransposons, two HTTs between Morus notabilis and Ziziphus jujuba, and five between Malus domestica and Pyrus bretschneideri were identified. Further analysis revealed that these LTR retrotransposons had functional structures, and the copy insertion times were lower than the dating of HTTs, particularly in Mn.Zj.1 and Md.Pb.3. Altogether, the results demonstrate that LTR retrotransposons still have potential transposition activity in host genomes. These results indicate that HTT events are another strategy for exchanging genetic material among species and are important for the evolution of genomes.
水平转座元件转移 (HTT) 事件在大量物种中发生，并在真核生物基因组的组成和进化中发挥重要作用。HTT 也被认为是促进基因组变异和生物创新的有效力量。本研究通过比较 20 个保守基因的序列保守性和反转录酶 (RT) 的 K/K 值，利用生物信息学方法在蔷薇科的七个已测序物种中鉴定和分析了 HTT 事件，估计 HTT 的时间，并分析了系统发育关系。鉴定出了 7 个涉及长末端重复 (LTR) 逆转录转座子的 HTT 事件，2 个 HTT 事件发生在桑和枣之间，5 个 HTT 事件发生在苹果和梨之间。进一步分析表明，这些 LTR 逆转录转座子具有功能结构，拷贝插入时间低于 HTT 的时间，特别是在 Mn.Zj.1 和 Md.Pb.3 中。总之，结果表明 LTR 逆转录转座子在宿主基因组中仍具有潜在的转座活性。这些结果表明，HTT 事件是物种间交换遗传物质的另一种策略，对基因组的进化至关重要。
