tRNA序列的进化网络研究

THE EVOLUTIONARY NETWORK STUDY OF tRNA SEQUENCES

根据tRNA序列的反密码子,把3420条tRNA序列分成了21组,其中包括20组氨基酸及1组Stop。通过tRNA序列的相似度构建了1组整体网络和21组子网络,并计算了它们在不同相似度下的平均度、平均聚类系数以及平均最短路径。通过分析、比较和讨论网络中的三个重要参数,进一步说明点突变是tRNA序列进化的重要机制,并反映了它们的进化近似符合中性理论,且在同一组氨基酸和Stop内的tRNA序列在进化历史上的同源关系更密切;同时表明了tRNA序列在进化过程中具有自相似性。

According to the different anticodons of tRNA sequences, 3420 tRNA sequences were divided into 21 groups, including 20 groups of amino acids and one group of Stop. Networks were constructed by the sequences similar degree, including one whole tRNAs network and 21 subnetworks. The average degree and the average clustering coefficient were calculated, as well as the average shortest path in different networks based on the different similar degree. After analyzing, comparing and discussing three important parameters in the different networks, on one hand, it is further indicated that the point mutation of tRNA sequences is the important evolutionary mechanism and the evolution of tRNA sequences approximately accorded with the neutral theory; on the other hand, it is also reflected that tRNA sequences have closer homologous relationships in the evolutionary history during the same groups of the amino acids and Stop, and they have the self-similarity property in the process of evolution.