Environmentally related patterns of reproductive modes in the aphid Myzus persicae and the predominance of two 'superclones' in Victoria, Australia
Environmentally related patterns of reproductive modes in the aphid Myzus persicae and the predominance of two 'superclones' in Victoria, Australia
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DOI：
10.1046/j.1365-294x.2003.01998.x
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发表时间：
2003-12-01
影响因子：
4.9
通讯作者：
Sunnucks, P
中科院分区：
文献类型：
--
作者：
Vorburger, C;Lancaster, M;Sunnucks, P
与有性亲属自然共存的无性生物可能是理解性维持和重组的关键，这是进化生物学中长期存在的问题。这种情况适用于澳大利亚东南部的桃蚜（Myzus persicae），那里的周期性孤雌生殖与专性孤雌生殖形成混合种群。我们从维多利亚州的几个地区收集了桃蚜，在七个微卫星位点对它们进行了基因分型，并通过实验确定了它们的繁殖模式。生殖模式的地理分布与两个环境变量相关，这两个环境变量对专性孤雌生殖和周期性孤雌生殖有不同的影响。专性孤雌生殖在寒冷冬季的地区较少出现，因为它们不能产生抗冻的卵，而周期性孤雌生殖则受到其主要寄主桃子的可用性的限制，而桃子是在桃子上进行有性繁殖的。克隆多样性随着样本中周期性孤雌生殖的比例而增加，因为它们往往具有独特的微卫星基因型，而许多专性孤雌生殖是相同基因型的副本。两种专性无性基因型非常丰富且分布广泛，一种占整个集合的 24%，另一种占整个集合的 17.4%。这两种非常成功的基因型都存在于大多数收集站中。遗传群体结构虽然很重要，但很弱，当样本减少到每种基因型只有一个代表时，多位点 F-ST 仅 0.021。有趣的是，平均而言，专性孤雌生殖比周期性孤雌生殖具有更多的杂合性，并且在各个位点的两个等位基因之间表现出更大的等位基因大小差异。这种惊人的模式可能是由杂交引起的，而我们没有证据证明这一点，或者可能反映了先前提出的无性蚜虫谱系内微卫星等位基因的有偏突变分歧的模型。
Asexual organisms that naturally coexist with sexual relatives may hold the key to understanding the maintenance of sex and recombination, a long-standing problem in evolutionary biology. This situation applies to the peach-potato aphid, Myzus persicae, in southeastern Australia where cyclical parthenogens form mixed populations with obligate parthenogens. We collected M. persicae from several areas across Victoria, genotyped them at seven microsatellite loci and experimentally determined their reproductive mode. The geographic distribution of reproductive modes was correlated with two environmental variables that differentially affect obligate and cyclical parthenogens; obligate parthenogens were less frequent in areas with cold winters because they cannot produce frost-resistant eggs while cyclical parthenogens were limited by the availability of their primary host, peach, on which sexual reproduction takes place. Clonal diversity increased with the proportion of cyclical parthenogens in a sample because they tended to have unique microsatellite genotypes, whereas many obligate parthenogens were copies of the same genotype. Two obligately asexual genotypes stood out as being very abundant and widespread, one constituting 24% and the other 17.4% of the entire collection. Both of these highly successful genotypes were present in the majority of all collection sites. Genetic population structure was weak, albeit significant, with a multilocus F-ST of only 0.021 when samples were reduced to only one representative of each genotype. Interestingly, obligate parthenogens were, on average, more heterozygous and exhibited larger allele size differences between the two alleles at individual loci than cyclical parthenogens. This striking pattern could result from hybridization, for which we have no evidence, or may reflect the previously proposed model of biased mutational divergence of microsatellite alleles within asexual aphid lineages.