Evolution of bric-a-brac regulation in Drosphilinae

描述（由申请人提供）：进化生物学领域长期以来一直对形态进化的分子基础感兴趣;然而，清晰的理解仍然难以捉摸。果蝇亚群的腹部色素沉着是一个很好的研究性状，适合研究，以确定在出现相似和不同的色素沉着模式的遗传变化达到高潮。除了不同的色素沉着模式，很明显，根据遗传学，类似的色素沉着模式已经独立出现。在黑腹物种组性二形，部分特定的色素沉着最近演变。雄性的末端腹部节是深色的，而雌性的所有节都是浅色的。近缘的物种群是单形的，即所有的体节在两性中都是浅色的。在所有物种中，色素沉着是在表达色素沉着抑制因子bric-a-brac（bab）的基因产物的地方被阻止的。在二形物种中，一个新进化的电路，涉及同源异型和性别决定的输入抑制bab表达的终端部分的男性，但不是女性。这项建议将分析如何果蝇bab基因调控元件已演变为整合反应的同源异型和性别决定的输入和程度，相似和不同的腹部色素沉着模式已通过修改orthopediabab序列的演变。从果蝇亚科增强子进化和功能机制的洞察将很可能适用于理解脊椎动物中的顺式调控元件，因为类似的序列改变在人类中具有重要的医学意义。

DESCRIPTION (provided by applicant): The field of evolutionary biology has long been interested in the molecular basis of morphological evolution; however a clear understanding remains elusive. Abdominal pigmentation in the subgroup Drosophilinae is a well studied trait suitable for studies to identify the genetic changes culminating in the emergence of similar and diverse pigmentation patterns. In addition to diverse pigmentation patterns it is apparent, based on phylogeny, that similar patterns of pigmentation have appeared independently. In the melanogaster species group sexually dimorphic, segment specific pigmentation has recently evolved. The terminal abdominal segments of males are dark, whereas all segments are lightly pigmented in females. Closely related groups of species are monomorphic, i.e. all segments are lightly pigmented in both sexes. In all species, pigmentation is prevented where the gene products of bric-a-brac (bab), a repressor of pigmentation, are expressed. In dimorphic species, a newly evolved circuitry involving homeotic and sex-determination inputs represses bab expression in the terminal segments of the male, but not the female. This proposal will analyze how Drosophila melanogaster bab gene regulatory elements has evolved to integrate responsiveness to homeotic and sex-determination inputs and the extent that both similar and diverse abdominal pigmentation patterns have evolved through the modification of orthologous bab sequences. Insight from the mechanisms of enhancer evolution and function in Drosophilinae will very likely apply to the understanding of cis-regulatory elements in vertebrates as similar sequence alterations have significant medical implications in humans.