环境因子对中国海矮拟帽贝种群遗传多样性的影响

Effects of environmental factors on genetic diversity of Patelloida pygmaea along the China Sea

采用聚合酶链式反应和直接测序的方法研究了中国海矮拟帽贝(Patelloida pygmaea) 13个地理种群环境因子对其遗传多样性的影响。137个样本的COI部分序列(601 bp)中共发现217个多态位点,转换颠换比1. 25,界定30个单倍型。汕头种群呈现较高的遗传多样性,威海种群呈现较低的遗传多样性。与环境因子相关性分析发现,矮拟帽贝遗传多样性与年均温度、年均降水量、年均水汽压呈显著正相关(P <0. 05),与纬度、年均温度变异系数、日照百分率、日照时数呈显著负相关(P <0. 05)。形态主成分分析矮拟帽贝长重比(L/DW)、宽重比(W/DW)、高重比(H/DW)为形态变异主成分,且与年均降水量变异系数呈显著负相关(P <0. 05)。温度、降水、日照、水汽压是影响中国海矮拟帽贝遗传多样性的主导因子,南方种群比北方种群有更高的遗传多样性。

Patelloida pygmaea,widely distributed in the intertidal zone along the coast of China,can be used as a model organism for the study of ecological genetics,because it is suitable for a wide range of living environments and is significantly influenced by historical events,current environmental and climatic factors.In this study,the mitochondrion DNA cytochrome c oxidase subunit I(mt DNA COI)gene of P.pygmaea was selected as a molecular marker to study the effects of environmental factors on morphological variation and genetic diversity of P.pygmaea.We collected 137 samples from 13 populations along the coast of China.A total of 10 absolute morphology measurements were selected and converted into relative measurements.The partial sequence of mt DNA COI gene(601 bp)was obtained by polymerase chain reaction(PCR)and DNA sequencing.The base content of mt DNA COI gene was A 24.10%,T 37.27%,C 16.53%,G 22.10%,and a total of 217 polymorphic loci were found,containing 139 transformations and 110 transversions(transformation/transversion=1.25),and 30 haplotypes were defined(21.89%of the total sample).Compared with 13 populations of P.pygmaea,the Shantou population showed higher genetic diversity and haplotype diversity was 0.855±0.08 5,the nucleotide diversity was 0.091 4±0.048 3,and the Weihai population showed the lowest genetic diversity(haplotype diversity 0.200±0.154;nucleotide diversity 0.003±0.000 5).The results of AMOVA showed that the genetic variation of P.pygmaea was mainly derived from among populations(89.57%,P<0.001).The correlation analysis between environmental factors and genetic diversity showed that the genetic diversity of P.pygmaea was significantly positively correlated with annual average temperature,annual average precipitation and annual average vapor pressure(P<0.05),and was significantly negatively correlated with latitude,variation coefficient annual average temperature,sunshine duration and sunshine percentage(P<0.05).The results of correlation analysis between environmental factors and morphological factors showed that the principal components of morphological variation(length/dry weight,width/dry weight and height/dry weight)were significantly negatively correlated with the annual average precipitation(P<0.05).Temperature and precipitation were the dominant factors affecting the genetic diversity of P.pygmaea,and southern populations had higher genetic diversity than northern populations in China.The higher the annual mean temperature is,the higher the genetic diversity of the population is.It is speculated that environmental temperature is the direct factor affecting P.pygmaea metabolism and sexual maturity,and then affects population genetic diversity.The more stable the temperature is,the higher the genetic diversity is,which is basically consistent with other mollusc ecological research results.The effect of precipitation on water vapor content in the air is another major factor affecting genetic diversity of P.pygmaea.And rainfall shortens sunshine hours,ultimately leading to increased genetic diversity.The stable environment leads to higher population genetic diversity for P.pygmaea along the coast of China.