Dissertation Research: The Role of Hybridization in the Evolution and Diversification of Heliconius Butterflies

进化研究的主要目标之一是解释新物种起源的机制。其中一个受到较少关注的机制是由于先前建立的物种之间的杂交而形成的新物种（或通过种间杂交形成的物种）。为了了解新物种是如何通过杂交产生的，该项目将追踪最近通过杂交产生的热带蝴蝶Heliconius pachinus和它的亲本物种之一H. cydno之间的分化历史。据推测，自人类起源以来，自然选择导致了物种完整性维持机制的进化。这个项目将通过检查这些机制和比较两个物种在其分布范围内的基因组成来确定这两个物种之间发生了多少总体的基因交换。尽管杂交在动物进化中的作用比以往任何时候都受到越来越多的关注，但在动物中很少有通过杂交形成物种的明确例子。一旦完成，这项研究将通过杂交提供最完整的物种形成解释之一。此外，这里提出的分化机制是一个新颖而令人兴奋的过程，通过这个过程，物种形成可能在这个属和其他属中多次发生。这种令人难以置信的相似性长期以来一直令生物学家感到惊讶，至今仍缺乏一个机制的解释。这里提出的假设很可能是对这整个现象的解释。

One of the primary goals of evolutionary research is to explain the mechanisms by which new species originate. One such mechanism that has received relatively little attention is the formation of new species due to interbreeding between previously established species (or, speciation via interspecific hybridization). In an effort to understand how new species originate due to hybridization, this project will trace the history of divergence between Heliconius pachinus, a tropical butterfly species that recently originated via hybridization, and one of its parental species, H. cydno. It is hypothesized that since the origin of the H. pachinus form, natural selection has led to the evolution of mechanisms by which species integrity is maintained. This project will determine how much overall genetic exchange is occurring between these two species by examining these mechanisms and by comparing the genetic makeup of both species throughout their range.Although the role of hybridization in animal evolution is receiving more attention than ever, there are few clear examples of speciation via hybridization in animals. Once finished, this study will provide one of the most complete explanations of speciation via hybridization. Furthermore, the mechanism of divergence proposed here is a novel and exciting process by which speciation may have occurred many times in this genus and others. The incredible correspondence of mimetic Heliconius species pairs has long amazed biologists and still lacks a mechanistic explanation. The hypothesis put forward here could well be the explanation for this entire phenomenon.