Evolution of bric-a-brac regulation in Drosphilinae

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 一个明确的理解仍然难以捉摸。果蝇亚群的腹部色素沉着是一个研究得很好的特征 适用于识别最终导致相似和不同色素沉着的遗传变化的研究 模式。根据系统发育，除了不同色素沉着模式外，还有相似的模式 色素沉着已独立出现。在黑腹蛇种群中，性别二态，特定于节段 色素沉着最近发生了变化。雄性的腹部末端是黑色的，而所有的腹部都是黑色的。 雌性的皮肤颜色较浅。密切相关的物种群是单态的，即所有的节段都有轻微的色素 男性和女性都有。在所有物种中，当brc-a-brac(Bab)的基因产物是 色素沉着，是表现出来的。在二态物种中，一种新进化的涉及同源异型和性别决定的回路。 在雄性的末端节段输入repressebab的表达，但在雌性不输入。这份提案将分析 果蝇Bab基因调控元件如何进化以整合对同源异型和 性别决定的输入以及相似和不同的腹部色素沉着模式进化的程度 通过修改同源的Bab序列。从增强子进化和增强机制的洞察 果蝇亚科的功能很可能应用于理解脊椎动物中类似的顺式调节元件 序列改变对人类有重大的医学意义。

The field of evolutionary biology has long been interested in the molecular basis of morphological evolution; however a clear understandingremains elusive. Abdominal pigmentation in the subgroup Drosophilinae is a well studiedtrait suitable for studies to identify the genetic changes culminating in the emergence of similar and diversepigmentation patterns. In addition to diverse pigmentation patternsit is apparent, based on phylogeny, that similar patternsof pigmentation haveappeared independently. In the melanogaster speciesgroup sexually dimorphic, segmentspecific pigmentation has recently evolved. The terminal abdominal segmentsof males are dark, whereas all segmentsare lightly pigmentedin 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 represserof pigmentation, are expressed. In dimorphic species, a newly evolved circuitry involving homeotic and sex-determination inputs repressesbab expression in the terminal segments of the male, but not the female. This proposal will analyze how Drosophila melanogaster bab gene regulatory elements has evolvedto integrate responsiveness to homeotic and sex-determination inputs and the extent that both similar and diverse abdominal pigmentation patterns haveevolved through the modification of orthologous bab sequences. Insight from the mechanisms of enhancer evolution and function in Drosophilinae will very likely apply to the understandingof cis-regulatoryelements in vertebrates as similar sequence alterationshave significant medical implications inhumans.