DISSERTATION RESEARCH: Genetic basis of parallel flower color shifts in Penstemon

当一种特定的进化变化，比如颜色，在相关生物中独立进化时，这种变化可能是由于所有群体在发育途径的同一阶段发生的突变，也可能是由于不同的突变。pi将通过使用Penstemon野花来研究这个问题，Penstemon由近300个品种组成，其中大多数都有蓝色或紫色的花朵。然而，在大约15-20个亚群中发现了鲜红色的花朵，这些变化至少独立进化了10次。红色的花朵可能是为了吸引蜂鸟作为传粉者而适应的。在penteston中发现的产生花色素类型的生化途径是很容易理解的。pi打算测试这些重复或平行的适应性进化事件是由于植物亚群之间相似的遗传变化还是不同亚群之间不同的遗传变化。这项研究是极少数研究平行进化的遗传基础的研究之一，以及某些类型的遗传变化是否比其他类型的遗传变化更常被观察到作为适应性进化的基础。此外，它将解决更广泛的问题，即适应性进化的遗传基础是可预测的还是不可预测的。pi正在将当地高中和杜克大学本科生的指导纳入该项目。该研究系统为平行适应进化提供了一个清晰且易于描述的例子；pi将致力于将其发展为理解平行进化的遗传基础的潜在教科书范例。

When a particular evolutionary change, such as a color, has evolved independently in related organisms, the change could be due to a mutation in the same stage of a developmental pathway in all the groups, or it could be due to different mutations. The PIs will examine this problem by using the wildflower genus Penstemon, which is made up of nearly 300 species, most of which have blue or purple flowers. However, bright red flowers are found in about 15-20 subgroups, and these changes evolved independently at least 10 times. The red flowers are probably an adaptation to attract hummingbirds as pollinators. The biochemical pathway that produces the types of flower pigments found in Penstemon is well-understood. The PIs intend to test whether these repeated or parallel episodes of adaptive evolution are due to similar genetic changes across subgroups of plants or different genetic changes in different subgroups. This study is one of a very few that addresses the genetic basis of parallel evolution, and whether certain types of genetic changes are more often observed to underlie adaptive evolution than others. Furthermore, it will address the broader question of whether the genetic basis of adaptive evolution is predictable or unpredictable.The PIs are integrating mentorship of local high school and Duke University undergraduate students into this project. This study system provides a clear and easily described example of parallel adaptive evolution; the PIs will work towards developing it as a potential textbook example for understanding the genetic basis of parallel evolution.