Conservation of Meiotic Recombination Sites in the Human Genome

描述（申请人提供）：减数分裂重组是重要的生物学过程之一，可能与许多人类疾病有关。在人类中，已知减数分裂重组主要聚集在某些称为重组热点的“重组位点”。虽然重组热点经常在不同人类个体的相同位置被发现，但对它们的保护知之甚少。在我们提出的研究中，一种假设认为人类基因组中的重组热点是高度保守的，但会发生实质性的变化，这些变化可能导致新位点的产生，并削弱和消灭现有位点。为此，18号染色体的短臂将被用作研究的对象。在第1阶段，将对3名男性（每人3000名）的9000个单精子样本进行全基因组扩增（WGA）后，对4000个单核苷酸多态性（snp）位点进行基因型分析。这将通过使用P.I.开发的高通量基因分型方法来完成的实验室。这一轮分析的完成将检测和定位沿染色体臂长度约4.8 kb的重组热点区域。这些位点将进一步定位到小于1kb的区域，通过对位于包含交叉区域的另外4000个snp进行基因分型。所有包含交叉的区间（n = 500至600）都将进行守恒分析。所有这些时间间隔内的重组率将在来自两个种族的20名精子捐献者中确定，通过使用先前报道的方法分析汇集的精子样本，允许选择性扩增和检测包含重组交叉的序列。研究结果可能首次用于大规模系统地研究重组热点的保守性，这将有助于理解人类基因组遗传结构的动力学和设计疾病关联研究。

DESCRIPTION (provided by applicant): Meiotic recombination is one of the important biological processes, and may be responsible for many human diseases. In humans, meiotic recombination is known to be clustered mostly at certain "recombination sites" known as recombination hotspots. Although recombination hotspots are often found at the same locations in different human individuals, very little is known about their conservation. In the proposed study, a hypothesis that recombination hotspots in the human genome are highly conserved but are subjected to substantial changes which may be responsible for the generation of new sites, and weakening and extinguishing existing sites. To do so, the short arm of chromosome 18 will be used as the subject for the study. In the first step of the project, 9,000 single sperm samples from three human males, 3,000 each, will be subjected to genotype analysis at 4,000 loci of Single Nucleotide Polymorphisms (SNPs) after whole genome amplification (WGA). This will be done by using a high-throughput genotyping approach developed in the P.I.'s laboratory. Completion of this round of analysis will detect and localize the recombination hotspots to ~4.8 kb regions along length of the chromosomal arm. These spots will be further localized to <1 kb regions by genotyping an additional 4,000 SNPs located in the regions containing crossovers. All crossover-containing intervals (n = 500 to 600) will be subjected to the conservation analysis. Recombination rates in all these intervals will be determined in 20 sperm donors from two ethnic groups by analyzing pooled sperm samples using a previously reported method allowing selectively amplification and detection of sequences containing recombination crossovers. The resulting data may be used, for the first time, to systematically examine the conservation of recombination hotspots on a large-scale, which will help understand the dynamics of the genetic structure of the human genome and design disease association studies.