Coexistence problem of closely related species during speciation

在本项目中，我们研究了物种形成过程中近缘物种的共存问题。在物种形成过程中，密切相关的物种可能会与新进化的种群相互作用。在这里，新进化的种群与其他密切相关的物种的共存成为建立新物种的关键因素。在这个项目中，我们研究了三种类型的共存模型，作为这种共存的规范模型。（1）螺类手性的演化模式少数陆生螺类常表现为左旋卷曲，而几乎所有的海生螺类都是右旋卷曲。在某些种类的蜗牛中，左手卷曲出现在许多种群中的少数（非常低的密度）个体中;在其他种群中，很少有种群是左手的。在少数物种或某些分类群中，物种和分类群完全是左撇子。在这里，我们建立了一个物种形成模型，从右卷曲到左卷曲。我们引入左右基因和显性开关基因。通过模拟 ...更多信息 我们发现这种从右向左卷曲的物种形成是一种罕见的事件。这可以解释蜗牛中通过手性转换的单基因物种形成。我们为这种单基因推测提供了遗传学/生物遗传学证据。（2）草地群落格点生态系统模型建立了草地群落中两个物种的格点空间模型。我们假设一个竞争性的上级物种在可能的情况下可能会入侵劣等物种。通过这种替换，我们展示了两个物种的广泛共存，当不包括这种相互作用时，共存是绝对不可能的。（3）多物种浮游生物群落格点模型建立了一个由10种浮游生物组成的格点生态系统。在这里，我们假设增长率略有不同。这种生长差异也取决于营养条件。在这个生态系统中，数学上只有一个物种（具有高增长率）应该排除所有其他物种。然而，我们评估了十到几十万代的共存，假设这是生态上可行的世代时间尺度。在这样的生态时间尺度下，几乎所有的物种都可以在格子空间模型中共存，没有优势种。相反，当假设全球相互作用时，一个物种支配所有其他物种（非空间版本的晶格模型）。因此，我们表明，几十个物种可以共存的生态时间尺度上，即使在一个非常小的格子生态系统，如果当地的相互作用。少

In this project, we studied the coexistence problem of closely related species during speciation process. During speciation, closely related species may interact with the newly evolving populations. Here the coexistence of newly evolving populations with other closely related species becomes a key factor for the establishment of such populations as a new species. In this project, we investigate three types of coexistence model as a canonical model of such coexistence.(1)Evolutionary model of chirality in snailsA few land snails often shows left handed coiling, whereas almost all sea snails are right handed. In some species of snails, left handed coiling appears in few (very low density) individuals in many populations ; in others, few populations are left handed. In few species or in some taxonomic group, species and taxa are totally left handed. Here we build a speciation model from right coiling to left coiling. We introduce left and right genes with dominance switch genes. By simula … More tion, we show such speciation from right to left coiling occurs as a rare event. This may explain the single gene speciation by chirality switching in snails. We showed the genetic/philogenetic evidence for such single gene specation.(2)Lattice ecosystem model of grassland communityWe build a lattice space model of two species in a grassland community. We assumed a competitively superior species may invade the inferior species when possible. With this replacement, we show a wide range of coexistence for two species, when coexistence is absolutely impossible when such interactions are not included.(3)Lattice model of multispecies plankton communityWe build a lattice ecosystem of 10 planktonic species. Here we assume a slight difference in growth rates. This growth difference is also dependent on nutritional conditions. In this ecosystem, mathematically only one species (with high growth rates) should exclude all other species. However, we evaluated the coexistence for ten to hundreds thousand generations, assuming this is ecologically feasible scale for generation time. In such ecological time scale, almost all species can coexist without dominant species in lattice space model. In contrast, one species dominate over all other species, when global interactions are assumed (non spatial version of lattice models). Thus we showed that tens of species can coexist during ecological time scale even in a very small lattice ecosystem if local interactions is assumed. Less