Molecular Genetics of Drosophila Hybrid Lethality

果蝇杂交致死率的分子遗传学

• 批准号: 8130639
• 负责人: DANIEL A BARBASH
• 金额: $ 29.15万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8130639
• 关键词: Address; Alleles; Animals; Biological Process; Biology; Cell Nucleus; Cell division; Chromatin; Chromosomes, Human, Pair 3; Code; Complex; DNA; DNA Sequence; Data; Defect; Drosophila genus; Drosophila melanogaster; Employee Strikes; Essential Genes; Evolution; Functional disorder; Gene Dosage; Gene Expression Regulation; Genes; Genetic; Genetic Polymorphism; Genome; Goals; Heterochromatin; Human; Hybrids; Image; Individual; Interphase; Lead; Life; Maintenance; Methods; Modeling; Molecular; Molecular Cloning; Molecular Genetics; Morphology; Nuclear; Orthologous Gene; Pathway interactions; Pattern; Phenotype; Plants; Population; Process; Property; Protein Binding; Proteins; Reading; Recording of previous events; Regulation; Relative (related person); Resolution; Screening procedure; Sterility; Structure; System; Testing; Transgenic Organisms; base; chromatin immunoprecipitation; chromatin modification; chromosome replication; driving force; fitness; genetic analysis; hybrid gene; killings; loss of function; loss of function mutation; male; public health relevance; reproductive; research study

DESCRIPTION (provided by applicant): Understanding how new species form is a fundamental problem in biology. Speciation occurs as reproductive barriers form between diverging populations. One type of reproductive barrier is the sterility and lethality of interspecific hybrids. These hybrid incompatibilities are caused by deleterious interactions between genes that have evolved independently in each diverging population. This proposal is based on the previous identification of two genes, Hmr and Lhr, which interact to cause hybrid lethality between the fruit fly species Drosophila melanogaster and Drosophila simulans. A major goal is to understand how these genes kill hybrids, and how the interaction between them is related to their patterns of DNA sequence divergence. One specific hypothesis is that Hmr and Lhr cause hybrid lethality by disrupting the structure and regulation of chromatin, the complex of DNA and associated proteins that controls and is essential for gene regulation, chromosome replication and cell division, and the maintenance of nuclear morphology. High-resolution imaging of chromatin-associated proteins and cytological studies of interphase nuclei will be used to test this hypothesis. The Hmr and Lhr genes encode proteins that have relatively high sequence divergence between the hybridizing species. A second hypothesis is that these diverged proteins will localize to different DNA sequences through their interactions with chromatin. This hypothesis will be tested by cytological methods and by performing chromatin immunoprecipitation (ChIP) followed by short- read sequencing of the recovered DNA. Interactions between the proteins encoded by Hmr and Lhr will also be investigated to determine whether these interactions are disrupted in interspecific hybrids. One striking aspect of the divergence of the Lhr gene is that D. simulans contains a substantial insertion in its coding region compared to D. melanogaster. An unusual Lhr allele has been discovered from D. simulans that lacks this insertion and has additional sequence changes compared to wild type alleles. This allele does not cause hybrid lethality and it will be investigated in order to determine whether the insertion contributes to functional differences in the Lhr gene between D. melanogaster and D. simulans. A region of the genome has been found that appears to contain a new major-effect hybrid lethality gene. This gene will be identified in order to determine whether it interacts with Hmr and Lhr or instead defines an independent pathway leading to hybrid lethality. PUBLIC HEALTH RELEVANCE: This project will provide a mechanistic understanding of how barriers between species form. The genes that form these barriers are part of what makes each species unique. Understanding the consequences of the evolutionary patterns of these genes will help to reveal how species including humans maintain a functionally coherent genome.

描述（由申请人提供）：了解新物种如何形成是生物学中的一个基本问题。当不同种群之间形成生殖障碍时，就会发生物种形成。一种生殖障碍是种间杂种的不育性和致死性。这些杂交不相容性是由每个不同种群中独立进化的基因之间的有害相互作用引起的。该提议基于之前对两个基因 Hmr 和 Lhr 的鉴定，这两个基因相互作用导致果蝇种果蝇和模拟果蝇之间的杂交致死。一个主要目标是了解这些基因如何杀死杂种，以及它们之间的相互作用如何与它们的 DNA 序列分歧模式相关。一种具体的假设是，Hmr 和 Lhr 通过破坏染色质的结构和调节而导致杂交致死性，染色质是 DNA 和相关蛋白质的复合物，控制基因调节、染色体复制和细胞分裂以及核形态的维持，并且对于基因调节、染色体复制和细胞分裂以及核形态的维持至关重要。染色质相关蛋白的高分辨率成像和间期细胞核的细胞学研究将用于检验这一假设。 Hmr 和 Lhr 基因编码的蛋白质在杂交物种之间具有相对较高的序列差异。第二个假设是，这些不同的蛋白质将通过与染色质的相互作用定位到不同的 DNA 序列。这一假设将通过细胞学方法和染色质免疫沉淀 (ChIP) 以及随后对回收的 DNA 进行短读长测序进行检验。还将研究 Hmr 和 Lhr 编码的蛋白质之间的相互作用，以确定这些相互作用是否在种间杂种中被破坏。 Lhr 基因差异的一个显着方面是，与黑腹果蝇相比，拟果蝇在其编码区包含大量插入。从 D. simulans 中发现了一个不寻常的 Lhr 等位基因，它缺乏这种插入，并且与野生型等位基因相比有额外的序列变化。该等位基因不会引起杂种致死性，将对其进行研究以确定插入是否导致黑腹果蝇和拟果蝇之间 Lhr 基因的功能差异。已经发现基因组的一个区域似乎包含一个新的主要效应混合致死基因。将鉴定该基因以确定它是否与 Hmr 和 Lhr 相互作用，或者定义导致混合致死的独立途径。 公共卫生相关性：该项目将从机制上理解物种之间的障碍如何形成。形成这些障碍的基因是每个物种独一无二的部分原因。了解这些基因进化模式的后果将有助于揭示包括人类在内的物种如何维持功能上一致的基因组。