Dissertation research: To see or not to see or to see again: regressive evolution and Dollo's Law in North American cavefishes (Pisces: Amblyopsidae)

随着最近的几项研究声称，复杂的结构，如眼睛或昆虫的翅膀，在丢失后可以恢复，被称为多洛定律的进化真的不可逆转的假设已经成为一个越来越令人感兴趣的问题。例如，最近对美国东南部一个洞穴鱼家族的分析表明，一种具有功能眼睛的水面鱼类是从一个盲人的穴居祖先进化而来的。另一种选择是，眼睛有功能的祖先反复产生不同的盲穴居鱼物种。为了验证这些假设，这项研究检查了与眼睛发育有关的基因。在盲人和有视力的血统中，关于眼睛相关基因的分子变化，替代假说对物种之间的相似性和差异性做出了明确的预测。然而，差异可能是微妙的，检查多基因数据集将提供所需的力量来测试多洛定律与反向进化的预测。当其他分析认为复杂结构的再进化可能是可能的时，这项研究展示了一种前进的方向。这项研究将为脊椎动物中几个与眼睛和色素相关的基因的分子进化提供洞察力，并可能有助于理解人类的视觉功能障碍。此外，这项研究的发现将被纳入正在进行的教育和对当地学校和组织的推广工作中。教育活动将直面人们对进化中“使用和废弃”的常见误解，并促进对基因和环境如何共同影响特征的理解。

The hypothesis that evolution is truly irreversible, known as Dollo's Law, has become a question of increasing interest, as several recent studies have made claims that complex structures, such as an eye or insect wing, can be recovered after loss. For example, recent analysis of a family of cavefishes from the southeastern U.S. suggests that a surface-dwelling fish with functional eyes has evolved from a blind, cave-dwelling ancestor. The alternative is that an ancestor with functional eyes repeatedly gave rise to separate blind cavefish species. To test these hypotheses, this study examines genes involved in eye development. The alternative hypotheses make distinct predictions about similarities and differences between species with regard to molecular changes in eye-related genes in blind versus sighted lineages. However, the differences may be subtle and examining a multiple-gene dataset will provide the power needed to test the predictions of Dollo's Law versus reverse evolution. This study demonstrates a way forward when other analyses suggest, but cannot confirm, that reevolution of complex structures is likely.This study will provide insight into the molecular evolution of several eye- and pigment-related genes in a vertebrate and might aid understanding of visual dysfunctions in humans. In addition, discoveries from this research will be incorporated into ongoing education and outreach efforts to local schools and organizations. Educational activities will confront common misconceptions about "use and disuse" in evolution, and promote understanding of how genes and environments jointly affect traits.