The molecular basis of meiotic crossover distribution

我的实验室已经确定了一个基因的分子基础，该基因负责建立秀丽隐杆线虫减数分裂中交叉事件的分布。 这是一个重要的结果，因为表型orec-1是独特的，因为它改变了测量的交换事件的位置，而对重组频率、繁殖力或发育过程没有任何其他可测量的影响。 rec-1基因的一个显著特征是它在一级序列水平上与其他物种保守性差，尽管迄今为止表征的所有物种都显示出减数分裂模式，这是另一种说法，即交换的分布沿染色体沿着不均匀。 对于这一明显的悖论有许多解释;然而，这里将要检验的假设是，rec-1是一个例子， 减数分裂特异性功能，在功能上保守，但在其一级序列中不保守。 这一建议的基本原理是，它是选择性的物种，以保护其减数分裂功能从交叉物种使用物种特异性分子进行减数分裂的基本生物功能中涉及的过程是有利的。 所有有性生殖的个体广泛使用的过程。 为了验证这一假设，将在密切相关的物种中鉴定所提出的口腔学。这将通过检查rec-1侧翼的基因来实现，这些基因是保守的。 利用这些侧翼基因寻找rec-1在C.在线虫中，我们将在我们预期的rec-1的位置上寻找编码区。 我们已经做了一些初步的实验，发现在预期的位置有一个编码区，但它与rec-1的序列并不高度保守。为了确认编码区对应于rec-1基因，我们将在密切相关的物种C.布里格塞 C.将使用CRISPR系统突变（敲除）briggsae。 梭Briggsae突变体敲除和野生型菌株的特征在于沿沿着正向染色体的杂交分布。C. briggsae的同源基因与C. elegans和野生型菌株已经测序并表征了与C.优雅 因此，基本的工具可以用来解决这个问题，即所提出的直系同源物是否在两个物种中执行相同的功能。 此外，我们将研究如何通过识别与REC-1蛋白相互作用的伴侣来建立减数分裂模式。 为了做到这一点，我们将采取遗传学的方法，检查基因与已知减数分裂功能的相互作用，沿着分子方法来确定蛋白质的相互作用。 以这种方式描述负责一种现象的分子基础，这种现象一直是生物学中一个长期存在的突出问题的对象。

My laboratory has identified the molecular basis of a gene responsible for establishing the distribution of crossover events in meiosis of Caenorhabditis elegans.  This is a significant result because the phenotype o rec-1 is unique in that it alters the position of the measured crossover event without any other measurable effects on frequency of recombination, fecundity or developmental processes.  A notable feature of the rec-1 gene is that it is poorly conserved at the level of primary sequence with other species, even though all species characterized to date show a meiotic pattern, which is another way of saying that the distribution of crossing over is not uniform along a chromosome.  There are a number of explanations for this apparent paradox; however the hypothesis that will be tested here is that rec-1 is an example of a meiosis-specific function that is conserved functionally, but not in its primary sequence.  The rationale for this proposal is that it is selectively advantageous for a species to protect its meiotic functions from cross-speciation using species-specific molecules to perform the processes involved in the basic biological function of meiosis.  A process widely used by all sexually reproducing individuals. In order to test this hypothesis, the proposed orothologs will be identified in closely related species. This will be achieved by examining the genes flanking rec-1, which are conserved.  Using these flanking genes to find the syntenic region where rec-1 is situated in C. elegans, we will look for a coding region in the position where we expect rec-1 to be.  We have done some preliminary experiments and found that there is a coding region in the expected location, but one that is not highly conserved sequence-wise with rec-1. To confirm that the coding region corresponds to the rec-1 gene, we will characterize it in the closely related species, C. briggsae.  The gene in C. briggsae will be mutated (knocked out) using the CRISPR system.  The C. briggsae mutant knock-out and the wild-type strain will be characterized with regard to the distribution of crossing over along an orthologous chromosome. There are mutant strains in C. briggsae that identify orthologous genes to those in C. elegans and the wild-type strain has been sequenced and characterized with regard to synteny with C. elegans.  So the basic tools are available to address the question of whether or not the proposed ortholog performs the same function in the two species.  In addition, we will investigate how the meiotic pattern is established by identifying interacting partners with the REC-1 protein.  To do this we will take both a genetic approach, examining gene interactions with known meiotic functions along with a molecular approach to identify protein interactions.  In this way characterize the molecular basis responsible for a phenomenon that has been the object of a long-standing, out-standing question in biology.