Apte S, Gardner J P.A.
School of Biological Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, New Zealand
J Exp Mar Biol Ecol. 2001 Apr 15;258(2):173-194. doi: 10.1016/s0022-0981(01)00218-0.
Genetic variation in the endemic New Zealand greenshell mussel, Perna canaliculus (Gmelin 1791), was examined using starch-gel electrophoresis at seven protein-coding loci (Idh; Acon-1; Acon-2; Gpd; Pgi; Pgm; Pgd) in 35 populations (N=1038 mussels). For all loci and all populations, Fisher's exact tests indicated highly significant departures from Hardy-Weinberg equilibrium (HWE), but this overall result was caused by significant heterozygote deficiencies at only two loci (Pgm and Pgd), and in only three northern populations (Kuaotunu, Te Haumi and Days Bay). Allelic and genotypic differentiation between population pairs at individual loci and across all loci were nonsignificant, and genotypic disequilibrium at each locus pair was also nonsignificant for all populations. Genetic variation in all populations was high (mean heterozygosity, 0.210+/-0.113), while Nei's D among populations was very low (0.002+/-0.002). Low population subdivision (θ=-0.001+/-0.002) and high levels of gene flow (Nm(p)=10.18; Nm(θ)=infinity) also indicated that the single panmictic unit model best explains population genetic homogeneity in P. canaliculus over a north-south distance >2000 km. Lack of genetic subdivision in this species is discussed in light of two previous allozyme studies, with differing results: one suggested that a north-south division exists between greenshell mussel stocks, and the other suggested that population structure in this species can be explained through isolation by distance model modified by local hydrology.
利用淀粉凝胶电泳技术，在35个群体（N = 1038只贻贝）的7个蛋白质编码基因座（异柠檬酸脱氢酶；乌头酸酶-1；乌头酸酶-2；葡萄糖磷酸脱氢酶；磷酸葡萄糖异构酶；磷酸葡萄糖变位酶；6-磷酸葡萄糖脱氢酶）上，检测了新西兰特有的绿壳贻贝（Perna canaliculus，Gmelin 1791）的遗传变异。对于所有基因座和所有群体，费舍尔精确检验表明，其显著偏离哈迪-温伯格平衡（HWE），但这一总体结果仅由两个基因座（磷酸葡萄糖变位酶和6-磷酸葡萄糖脱氢酶）以及仅三个北部群体（库奥图努、蒂豪米和戴斯湾）的显著杂合子缺失所导致。各个基因座以及所有基因座上群体对之间的等位基因和基因型分化均不显著，并且所有群体中每个基因座对的基因型不平衡也不显著。所有群体的遗传变异程度较高（平均杂合度为0.210±0.113），而群体间的奈氏遗传距离D非常低（0.002±0.002）。低水平的群体细分（θ = -0.001±0.002）和高水平的基因流（Nm(p)=10.18；Nm(θ)=无穷大）也表明，单一随机交配单位模型最能解释在南北距离超过2000公里的情况下，绿壳贻贝群体的遗传同质性。结合之前两项不同结果的等位酶研究，讨论了该物种缺乏遗传细分的情况：一项研究表明绿壳贻贝种群存在南北分化，另一项研究则表明该物种的种群结构可以通过由当地水文条件修正的距离隔离模型来解释。
