GENETICS AND EVOLUTION OF MORPHOLOGY IN DROSOPHILA

描述：在之前的一个非常有成效的奖项中，PI开发了一种媒介 利用QTL进行遗传鉴定的分辨率图谱(约20 cM) 影响男性后叶形状和大小的因素。这个 拟议的研究将进一步将这张地图的分辨率提高到5-10厘米 已知含有某一因子的地区。第二个目标是使用 影响雄性形态的黑腹盘藻内的突变 并创造出杂交后叶来确定野生型 这些突变基因的等位基因导致了物种差异。 显示男性受限Lacz的增强子-检测器P元件插入 生殖盘中的表达将作为候选基因进行研究。一个 具有性别二态表达的纯合子可活插入物的集合在 手。将对这些基因进行筛查，以确定在这些基因中是否存在性二型致命插入 已被鉴定为含有QTL的染色体区域 种间分析。实验室将对X射线进行马赛克扫描 第三条染色体上的诱变及其对后叶的影响 形态学。这条染色体显示了最高密度的基因 种间杂交对雄性生殖器官形态的影响。 一旦在物种中确定了候选基因，它将被 在使用隐性功能丧失突变的杂交测试中进行评估， 将MEL中的突变体与3个姐妹分类群中的每一个进行杂交，并比较 产生的雄性表型与由类似的杂交产生的那些 野生型梅尔。一旦一个候选基因被明确地牵连到正常 后叶的发育与杂交种的男性不同，它会 从转录组织的角度对其进行克隆和鉴定， 蛋白质序列和表达模式。P-元件介导的转移 将来自其他物种的基因导入黑腹圆锥虫将提供一种 对该基因在男性生殖器发育中的作用进行了决定性的测试。 嵌合的基因结构将被用来进一步将基因分割成 对其影响负责的功能区到底要解决什么问题 序列的各个方面在形态上是相互关联的 物种之间的差异。基因和基因的多倍体效应 杂交形态的其他方面的功能区也将 调查过了。最终，这应该会提供有关 基因相对于自然界中的选择性力量的进化。

DESCRIPTION: In a very productive previous award, the PI developed a medium resolution map (scale of approximately 20 cm) using QTLs to identify genetic factors affecting the shape and size of the male posterior lobe. The proposed research will further resolve this map to a scale of 5-10 cm in regions already known to contain a factor. A second goal is to use mutations within D. melanogaster that affect the morphology of the male posterior lobe and create hybrids to determine whether the wild- type alleles of those mutant genes contribute to species differences. Enhancer-detector P-element insertions that exhibit male-limited lacZ expression in the genital disc will be studied as candidate genes. A collection of homozygous viable inserts with sex-dimorphic expression is in hand. These will be screened for sexually dimorphic lethal inserts in those chromosomal regions already identified as containing QTLs in the interspecific analysis. The lab will conduct a mosaic screen for X-ray induced mutations on the third chromosome and affecting posterior lobe morphology. This chromosome exhibits the greatest density of genes affecting male genital morphology in interspecific crosses. Once a candidate gene has been identified within the species, it will be assessed in a hybrid test using a recessive loss-of- function mutation, crossing the mutant in mel to each of the 3 sister taxa and comparing the resultant male phenotypes with those produced by similar crosses with wild-type mel. Once a candidate gene has been clearly implicated in normal development of the posterior lobe and in hybrid male differences, it will be cloned and characterized in terms of its transcriptional organization, protein sequence, and pattern of expression. P- element mediated transfer of the gene from other species into D. melanogaster will provide a conclusive test of the role of the gene in male genital development. Chimeric gene constructs will be used to further partition the gene into functional regions responsible for its effects to address exactly what aspects of the sequence are causally involved in the morphological differences between species. The pleotrpic effects of the gene and functional regions on other aspects of hybrid morphologies will also be investigated. Eventually, this should provide information regarding the evolution of genes vis-a-vis the selective forces operating in nature.