绶草的遗传多样性及地理分布格局分析

Analysis of Genetic Diversity and Geographical Distribution Pattern of Spiranthes sinensis

利用NCBI数据库数据,以绶草叶绿体matK序列和核基因ITS序列为主要研究对象,对绶草的遗传多样性及地理分布格局进行讨论分析,以期为绶草优良种质资源的遗传多样性评价提供有价值的参考。结果表明:绶草的matK序列比对后长度为512 bp,G+C含量32.4%,A+T含量67.7%,序列碱基组成具有明显的A/T偏好性,共检测到7个单倍型,总单倍型多样性Hd为0.644,总核苷酸多样性(π)为0.00316。绶草的ITS序列比对后长度为441 bp,G+C含量55.3%,A+T含量44.8%,共检测到15个单倍型,总单倍型多样性Hd为0.877,总核苷酸多样性(π)为0.00718,遗传分化系数Gst<Nst(Gst=0.39<Nst=0.64;Gst=0.26<Nst=0.50),说明绶草具有明显的谱系地理分布格局,基因流较低(Nm=0.14,Nm=0.25),失配分析的观测值曲线与期待值曲线都呈下降趋势并且呈现多峰,结合中性检测结果发现绶草物种居群保持稳定,没有发生过近期扩张现象。本研究得出印度、韩国、日本和歌县,中国喜马拉雅山脉地区遗传多样性较高,推测在第四纪冰期时绶草在印度、中国、朝鲜、日本等均可能存在冰期避难所。

In the present study,the genetic diversity and geographical distribution pattern of Spiranthes sinensis were discussed and analyzed by means of NCBI database data,taking matK sequence of chloroplast and ITS sequence of nuclear gene of Spiranthes sinensis as the main research object in order to provide valuable reference for genetic diversity evaluation of excellent germplasm resources of Spiranthes sinensis.The results showed that the length of matK sequence was 512 bp,the content of G+C was 32.4%,that of A+T was 67.7%.And the sequence base composition showed obvious A/T bias,a total of 7 haplotypes.Total genetic diversity was 0.644,and the total nucleotide diversityπwas 0.00316.It was also detected that the length of ITS sequence was 441 bp,the content of G+C was 55.3%,and the content of A+T was 44.8%.A total of 15 haplotypes were detected.It showed that the total genetic diversity was 0.877,and the total nucleotide diversity was 0.00718.The coefficient of transmission and differentiation Gst<Nst(Gst=0.39<Nst=0.64,Gst=0.26<Nst=0.50)showed that the Spiranthes sinensis has an obvious pedigree geographical distribution pattern,with low gene flow(Nm=0.14,Nm=0.25).A downward trend and multiple peaks in the observed value curve and expected value curve of the mismatch analysis.Combined with the neutral detection results,it is found that populations of Spiranthes sinensis species remained stable,without expansion recently.In this study,it has been found that the genetic diversity of the Spiranthes sinensis was obvious in India,South Korea,Wakayama in Japan and Himalayan mountains in China.Also,it has been speculated that there may be ice age refuges in India,China,Korea and Japan during the Quaternary ice age.