DISSERTATION RESEARCH: Examining Evidence for Phenotypic and Genetic Convergence in the Guppy (Poecilia reticulata)

趋同进化指的是不同物种中相似特征的起源，例如鸟类、蝙蝠和昆虫的飞行。人们通常认为，导致物种趋同进化的基因是相似的，但这仍然是一个悬而未决的问题。该方案采用了核酸测序方法，基因可以随时开启或关闭。然后将这些信息与孔雀鱼尾巴的颜色模式进行比较。尾色是一种高度可变的性状，在交配表现中起着关键作用。该项目将识别不同地点不同鱼类的颜色基因，以了解相同的基因特征是否会导致相似的模式。这项研究将通过回答有关进化可预测性的问题来推进科学知识，并将为美国种族最多样化的大学之一的本科生提供研究机会。这一建议侧重于趋同进化。具体来说，研究人员解决了两个问题：1)基因差异人群中个体的可见颜色模式有多相似？2)在种群中区分极端颜色模式的基因是否会在来自遗传分化位点的个体中趋同？如果会，是哪些趋同？对于第一个问题，研究人员将分析来自五个地点的雄性孔雀鱼的照片，并将图案按颜色分类。研究人员假设，在基因不同的种群中，雄性的颜色模式将会趋同。第二个问题将使用下一代DNA测序来回答。对于这五个位点中的每一个，将对彩色和非彩色尾巴的雄性的组织进行测序。将一个位点尾色型之间的差异表达基因与其他位点尾色型之间的差异表达基因进行比较，以检验收敛性。研究人员将能够确定表型趋同是否与相同基因的表达、相同途径内的不同基因或不同途径相关。

Convergent evolution refers to the origin of similar traits in different species, such as flight in birds, bats, and insects. It is often thought that the genes underlying convergent evolution within species are similar, but this is still an open question. This proposal uses a nucleic acid sequencing method to which genes are turned on or off at any time. This information is then compared with tail color patterns of guppies. Tail coloration is highly variable trait and plays a key role in mating displays. The project will identify color genes in different fish at different locations to understand if the same genetic signatures result in similar patterns. The study will advance scientific knowledge by answering questions concerning the predictability of evolution, and will provide research opportunities for undergraduates at one of the most ethnically diverse universities in the nation. This proposal focuses on convergent evolution. Specifically, the researchers address two questions: 1) How similar are visible color patterns among individuals from genetically diverged populations? and 2) Will genes differentiating extreme color patterns within a population be convergent among individuals from genetically diverged sites, and if so, which ones? For the first question, the researchers will analyze photographs of male guppies from five sites and sort the patterns into color categories. The researchers hypothesize that there will be convergence in the color patterns of males from genetically diverged populations. The second question will be answered using next generation DNA sequencing. For each of the five sites, tissues from males with colored and uncolored tails will be sequenced. The differentially expressed genes between tail color types at one site will be compared to the differentially expressed genes between tail color types at the other sites to test for convergence. The researchers will be able to determine if phenotypic convergence is correlated with expression of the same genes, different genes within the same pathway, or different pathways.