Sensitized Screen in the Diversity Outcross Mouse Population

描述(由申请人提供)：个人的基因构成影响他们对疾病或障碍的易感性，也可能影响疾病的严重性、预后，甚至治疗选择。大多数遗传变异在孤立的情况下产生微妙的影响，因此保留在种群中。然而，某些变异的组合是不相容的；然而，人们仍然不太清楚小基因扰动的积累如何破坏正常的动态平衡，并使组织对紊乱敏感。目前的项目将描述在敏感人群中分离的自然遗传变异是如何相互作用来破坏缓冲的 器官发育过程中转录网络的能力。这项拟议的研究将采用系统遗传学的方法来模拟小鼠胚胎性腺在性别决定过程中的转录网络。性腺出现在妊娠中期，有能力分化为睾丸或卵巢，而不受性别染色体构成的影响。这种独特的可塑性是由一个平衡的转录组赋予的，该转录组具有与两种不同的性别命运相关的特征。未能建立或维持一种性命(如睾丸)会导致性逆转为另一种性命(如卵巢)。已知遗传背景会影响性反转的易感性 通过破坏底层转录网络的平衡。拟议的敏化筛选将引入依赖于背景的性别逆转突变，以使遗传图谱人群对性别逆转敏感。这种高度多样化的遗传独特个体群体，即多样性外交(DO)群体，来自与新兴合作杂交(CC)重组近交系相同的8个创始人菌株，并捕获了全基因组范围内的高水平遗传变异，并提供了高图谱分辨率。目的1研究DO组已知的性别决定基因的一个子集在性腺中的表达，8株CC方正菌株和性别反转的Dax1/Nr0b1突变株。这项调查将提供DO群体中表达变异性的基线测量，并能够基于共表达关系对非定向转录网络进行建模。目的2将产生大量的DO胚胎，这些胚胎对Dax1/Nr0b1突变引起的性别反转敏感。基因组中影响性腺基因表达的区域(表达数量性状基因座，或eQTL)将通过RNA-Seq表达和密集的基因分型数据相结合来识别。由此得到的eQTL数据将被用于开发一个详细的性别决定预测网络模型。

DESCRIPTION (provided by applicant): An individual's genetic makeup influences their susceptibility to disease or disorder, and can also affect disease severity, prognosis, and even treatment options. Most genetic variants exert subtle effects in isolation, and are thus maintained in the population. However, certain combinations of variants are incompatible; yet it remains poorly understood how an accumulation of small genetic perturbations can compromise normal homeostasis and sensitize a tissue to disorder. The current project will characterize how natural genetic variation segregating in a sensitized population interacts to disrupt the buffering capacity of a transcription network during organ development. The proposed research will take a systems genetics approach to model the transcription network in the embryonic mouse gonad during sex determination. The gonad arises at mid-gestation competent to differentiate as a testis or ovary irrespective of sex chromosome constitution. This unique plasticity is conferred by a balanced transcriptome with features associated with both differentiated sexual fates. Failure to establish or maintain one sexual fate (e.g. testis) causes sex reversal to the alternative fate (e.g. ovary). Genetic background is known to affect susceptibility to sex reversal by unbalancing the underlying transcription network. The proposed sensitized screen will introduce a background-dependent sex-reversing mutation to sensitize a genetic mapping population to sex reversal. This highly diverse population of genetically unique individuals, the Diversity Outbred (DO) stock, is derived from the same eight founder strains as the emerging Collaborative Cross (CC) recombinant inbred strains, and captures genome-wide high levels of genetic variation and provides high mapping resolution. Aim 1 will characterize the expression of a subset of known sex determination genes in gonads from the DO panel, eight CC founder strains, and the sex-reversing Dax1/Nr0b1 mutant strain. This survey will provide a baseline measurement of expression variability in the DO population and enable the modeling of an undirected transcription network based on coexpression relationships. Aim 2 will derive a large population of DO embryos that are sensitized to sex reversal by the Dax1/Nr0b1 mutation. Regions of the genome that affect gene expression in the gonad (expression quantitative trait loci, or eQTL) will be identified from a combination of RNA-Seq expression and dense genotyping data. The resulting eQTL data will be used to develop a detailed predictive network model of sex determination.