Systems Genetics of Cocaine Preference in Drosophila

项目摘要 可卡因使用障碍（CUD）是一个重大的公共卫生和社会经济问题。可卡因是 参与了40%的与毒品有关的急诊室就诊，美国可卡因过量的比率是 稳步攀升然而，导致CUD的遗传基础仍然知之甚少。双胞胎研究 对CUD遗传学的研究提供了42- 79%之间的遗传率估计。然而，重要的遗传估计 没有指出哪些基因参与，以及它们如何在功能上相关。全基因组关联 CUD的GWAS研究受到无法控制环境因素的限制; 人类基因组限制了作图精度;由于难以招募参与者，样本量较小 因为可卡因的使用被定为犯罪。模式生物如果蝇 这是一种具有成本效益的替代方法，可以控制样本量、环境和遗传背景。可卡因 与果蝇的多巴胺转运体结合，就像在人类中一样，引发可卡因诱导的运动 表型果蝇中的GWAS由果蝇遗传参考组促进 （DGRP），野生衍生的、近交的、完全测序的品系的扩展集合，其提供了一个活的 自然变异我的目标是使用DGRP和系统遗传学方法来揭示遗传 可卡因相关表型的基础。在具体目标1中，我将研究基因的影响。 可卡因偏好的背景，通过使用微孔板筛选600个DGRP系的可卡因偏好 饲养层测定然后，我将执行GWAS，利用全基因组序列数据来识别遗传变异 与可卡因偏好有关。我将执行基因本体和KEGG的正交路径富集 分析，以及构建遗传相互作用网络，以牵连基因和可卡因参与的途径， 偏好在具体目标2中，我将量化可卡因暴露对行为和转录组学的影响， 有可卡因极端偏好的DGRP品系。对于25个表现出可卡因偏好的DGRP系和25个表现出可卡因偏好的DGRP系， 接近人口平均水平，我将评估可卡因对感觉运动整合的影响， 暴露。在具体目标3中，我将在功能上验证与可卡因相关的候选基因和变体 分别使用DGRP系的RNA干扰和样品外测试的偏好。完成这些 目的将导致果蝇可卡因偏好的系统遗传学模型，具有翻译潜力， 人类可卡因使用障碍。这个项目将训练我在先进的系统遗传学技术和分析 并为我的职业生涯做好准备，研究物质使用障碍的遗传学。

PROJECT SUMMARY Cocaine Use Disorder (CUD) represents a significant public health and socioeconomic concern. Cocaine is involved in 40% of drug-related emergency room visits, and rates of cocaine overdose in the United States are climbing steadily. Yet, the genetic underpinnings that predispose to CUD remain poorly understood. Twin studies on the genetics of CUD provide heritability estimates between 42-79%. However, significant heritability estimates do not indicate which genes are involved, and how they might be functionally relevant. Genome-wide association studies (GWAS) of CUD are limited by inability to control environmental factors; the haplotype structure of the human genome limiting mapping precision; and small sample sizes due to difficulty recruiting participants because of criminalization of cocaine use. Model organisms such as the fruit fly Drosophila melanogaster offer a cost-effective alternative where sample size, environment, and genetic background can be controlled. Cocaine binds to the dopamine transporter of Drosophila as it does in humans, eliciting cocaine-induced locomotor phenotypes. GWAS in Drosophila are facilitated by the Drosophila melanogaster Genetic Reference Panel (DGRP), an expanding collection of wild-derived, inbred, fully sequenced lines that provide a living library of natural variation. It is my goal to use the DGRP and a systems genetics approach to uncover the genetic underpinnings of cocaine-related phenotypes. In Specific Aim 1, I will investigate the impact of genetic background on cocaine preference by screening 600 DGRP lines for cocaine preference using the microplate feeder assay. I will then perform a GWAS, utilizing whole genome sequence data to identify genetic variants associated with cocaine preference. I will perform gene ontology and KEGG orthology pathway enrichment analyses, as well as construct genetic interaction networks to implicate genes and pathways involved in cocaine preference. In Specific Aim 2, I will quantify the behavioral and transcriptomic effects of cocaine exposure in DGRP lines with extreme cocaine preference. For 25 DGRP lines that exhibit cocaine preference and 25 lines near the population average, I will assess effects of cocaine on sensorimotor integration upon repeated exposures. In Specific Aim 3, I will functionally validate candidate genes and variants associated with cocaine preference using RNA interference and out-of-sample testing of DGRP lines, respectively. Completion of these aims will result in a systems genetics model of cocaine preference in Drosophila with translational potential for human cocaine use disorder. This project will train me in advanced systems genetics techniques and analyses and prepare me for a professional career in the study of the genetics of substance use disorders.