基于叶绿体DNA序列atpI-rsp2psbC-trnS的山药种质资源遗传多样性分析

Genetic diversity of yam germplasm revealed by chloroplast DNA sequences atpI-rsp2 and psbC-trnS

  • 摘要: 【目的】基于叶绿体DNA(cpDNA)序列atpI-rsp2psbC-trnS分析山药种质资源的遗传多样性,为山药种质资源鉴定、创新利用及新品种选育提供理论依据。【方法】以来自14个省(区)的64份山药种质为材料,对其atpI-rsp2psbC-trnS序列进行多态性扩增并测序,经拼接、比对后,利用MEGA 7.0计算种质间的遗传距离并构建系统发育进化树,并利用DNAsp 5.0分析核苷酸多态性,采用NET Framework 4.6.1绘制单倍型间的中介邻接网络结构。【结果】atpIrsp2和psbC-trnS序列合并序列长度为1938 bp,共有117个插入/缺失位点(IS)和14个变异位点(Vs),转换率(Si) 为49.1%,总体转换/颠换偏倚率(R)为0.928,共产生30种单倍型,其中有21种为独享单倍型,9种为共享单倍型,单倍型多样性(Hd)和核苷酸多样性(π)分别为0.9206和0.00139。atpI-rsp2序列和psbC-trnS序列及合并序列的Tajima’s D、Fu and Li’s D*和F*均为负值,其差异均未达显著水平(P>0.10),说明这2个序列在进化上符合中性进化模式。64份山药种质的遗传距离为0~0.003865,平均遗传距离均为0.001400。中介邻接网络结构分析结果显示,30种单倍型可分为3类,其中,H5为较原始单倍型。【结论】64份山药种质资源的遗传距离较近,遗传背景相似,可能是由于长期地区间引种导致,与地理距离不完全相关。atpI-rsp2psbC-trnS序列可用于山药物种鉴定和系统进化分析等研究领域。

     

    Abstract: 【Objective】The genetic diversity of 64 yam germplasm was analyzed based on the chloroplast DNA(cpDNA)sequences atpI-rsp2 and psbC-trnS to provide a theoretical basis for the selection,innovative utilization and breeding of yam germplasm resources.【Method】The atpI-rsp2 and psbC-trnS sequences of 64 yam germplasm collected from 14 provinces(regions)were amplified and sequenced for polymorphism. After mosaic and comparison,the genetic distance between germplasms was calculated by MEGA 7.0 and a phylogenetic tree was constructed. The nucleotide polymorphisms were analyzed by DNAsp 5.0 and NET Framework 4.6.1 was used to draw the intermediate adjacency network structure between haplotypes.【Result】The combined sequence length of atpI-rsp2 and psbC-trnS was 1938 bp,with con-tained 117 insert/missing sites(IS)and 14 variable sites(Vs). The conversion frequency(Si) was 49.1%,and the overall transition/transversion bias(R)value was 0.928,resulting in 30 haplotypes. Of these,21 haplotypes were exclusive and 9 haplotypes were shared,corresponding to a haplotype diversity index value(Hd)of 0.92063 and nucleotide diversity value (π)of 0.00139. The Tajima’s D values,Fu and Li’s D * and F * of the atpI-rsp2 sequence and the psbC-trnS sequence and the merged sequences were all negative,and the difference was not significant(P>0.10),suggesting the sequences in yams fitted the neutral evolutionary model. The genetic distance of 64 yam germplasm ranged from 0 to 0.003865 with an average of 0.001400. The results of the structure analysis of the intermediate adjacency network showed that the 30 haplotypes could be divided into three types,H5 was the primitive haplotype.【Conclusion】The 64 yam germplasm resources have close genetic distance and similar genetic background,which may be caused by long-term interregional introduction. It is not entirely correlated with geographical distance. atpI-rsp2 and psbC-trnS sequences can be used for species identification and the phylogenetic analysis of yam.

     

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