Phylogeography and population genetics reveal ring species patterns in a highly polymorphic California lily
Phylogeography and population genetics reveal ring species patterns in a highly polymorphic California lily
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DOI：
10.1111/jbi.14313
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发表时间：
2022-01-16
影响因子：
3.9
通讯作者：
Specht, Chelsea D.
中科院分区：
文献类型：
--
作者：
Hernandez, Adriana, I;Landis, Jacob B.;Specht, Chelsea D.
目的自然选择通常导致生殖性状的同质化，减少种群内的自然变异；因此，高度多态的物种在给定表型多样性的情况下，对于形成和维持基因流的机制提出了悬而未决的问题。我们使用一个综合框架来表征表型多样性，并评估进化史和种群遗传学如何影响加州特有百合的高度多态性质。地点：美国加利福尼亚州。蝴蝶百合(Calochortus Venustus)。方法总结集合种群和亚种群尺度上的表型多样性，探索空间表型分布。我们在物种范围内对174个个体进行了采样，代表了每个种群和每个表型的多个样本。我们使用限制性内切酶相关DNA测序(RAD-Seq)来检测种群集群、表型之间和种群之间的基因流动，推断单倍型网络，并重建祖先范围进化来推断历史迁徙和范围扩展。结果花瓣着色、远端斑点等种内多态花卉性状在地理上是有结构的，所推断的进化史与环种模式一致，该模式涉及一组从创建种群开始经历了遗传和表型变异的复合体。种群保持着相互联系，但已经沿着从南到北范围的分叉扩张而彼此分化，因此表明北部范围内向白色地貌类型的平行进化。因此，我们的系统地理分析显示，无论表型多样性如何，形态与种群遗传凝聚力都是一致的。主要结论高度多态的金鸡儿表型变异不是由于表型间的遗传分化，而是6个地理种群之间存在遗传凝聚力，其中一些种群保持了较高的种群内表型多样性水平。我们的结果表明，在不同的空间尺度上，将表型从基因型中分离出来，对多态分类群的分析大有裨益。我们根据环种的概念和确定我们报告的模式的适应意义的必要性来讨论结果。
Aim Natural selection typically results in the homogenization of reproductive traits, reducing natural variation within populations; thus, highly polymorphic species present unresolved questions regarding the mechanisms that shape and maintain gene flow given a diversity of phenotypes. We used an integrative framework to characterize phenotypic diversity and assess how evolutionary history and population genetics affect the highly polymorphic nature of a California endemic lily. Location California, United States. Taxon Butterfly mariposa lily, Calochortus venustus (Liliaceae). Methods We summarized phenotypic diversity at both metapopulation and subpopulation scales to explore spatial phenotypic distributions. We sampled 174 individuals across the species range representing multiple samples for each population and each phenotype. We used restriction-site-associated DNA sequencing (RAD-Seq) to detect population clusters, gene flow between phenotypes and between populations, infer haplotype networks, and reconstruct ancestral range evolution to infer historical migration and range expansion. Results Polymorphic floral traits within the species such as petal pigmentation and distal spots are geographically structured, and inferred evolutionary history is consistent with a ring species pattern involving a complex of populations having experienced sequential change in genetic and phenotypic variation from the founding population. Populations remain interconnected yet have differentiated from each other along a bifurcating south-to-north range expansion, consequently indicating parallel evolution towards the white morphotype in the northern range. Thus, our phylogeographical analyses reveal morphological convergence with population genetic cohesion irrespective of phenotypic diversity. Main conclusions Phenotypic variation in the highly polymorphic Calochortus venustus is not due to genetic differentiation between phenotypes; rather there is genetic cohesion within six geographically defined populations, some of which maintain a high level of within-population phenotypic diversity. Our results demonstrate that analyses of polymorphic taxa greatly benefit from disentangling phenotype from genotype at various spatial scales. We discuss results in light of ring species concepts and the need to determine the adaptive significance of the patterns we report.