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Computer Modeling of Genome Evolution during Sympatric Speciation[计算机模拟同域物种形成过程中基因组进化

Computer Modeling of Genome Evolution during Sympatric Speciation[计算机模拟同域物种形成过程中基因组进化
课程网址: http://videolectures.net/eccs07_cebrat_cmg/  
主讲教师: Stanislaw Cebrat
开课单位: 东京大学
开课时间: 2007-11-22
课程语种: 日语
中文简介:
在自然,甚至大型和泛滥的群体中,近亲繁殖系数可能相对较高,因为个体正在相对较短的距离内寻找性伴侣。我们模拟了这种种群在方格上的演化。将模拟结果与人群及其遗传库进行比较。特别地,我们使用累积去趋势散步的方法分析了沿着人染色体的重组斑点的分布。所有人类染色体(不包括没有重组伴侣的染色体Y)的重组频率在亚端粒区域(染色体的两端)较高,在染色体的中间部分相对较低。这类似于在计算机模拟群体中代表单倍型的位串中接受的重组事件的分布。在我们的模拟中,繁殖前的个体必须产生与单倍型(位串)之间的重组概率相关的配子。如果通过该重组产生的配子成功形成存活的受精卵,则认为重组事件被接受。在高近亲繁殖和低频率的基因组内重组中,一个基因组中的位串的中间部分彼此互补,而在末端通过纯化达尔文选择来消除缺陷等位基因。这种情况是同种物种形成后群体的特征。总之,染色体的中间部分更加保守,其结构似乎是属于较高分类群的原因,而在染色体末端则定位了负责物种内生物多样性的基因。
课程简介: In the natural, even large and panmictic populations, the inbreeding coefficient could be relatively high, because individuals are looking for sexual partners in the relatively short distances. We have simulated the evolution of such population on the square lattice. Results of simulations were compared to the human population and its genetic pool. In particular, we have analyzed distribution of recombination spots along the human chromosomes using the method of cumulative detrended walks. Frequency of recombination in all human chromosomes (excluding chromosome Y which has no partner for recombination) is higher in the subtelomeric regions (both ends of chromosomes) and relatively lower in the middle part of chromosomes. This resembles the distribution of accepted recombination events in the bitstring representing haplotypes in the computer simulated populations. In our simulations, individuals before reproduction have to produce gametes connected with some probability of recombination between haplotypes (bitstrings). We consider that recombination event is accepted if gamete produced by this recombination succeeded in forming the surviving zygote. Under high inbreeding and low frequency of intragenomic recombinations the middle parts of bitstrings in one genome complemented each other while at the ends the defective alleles are eliminated by purifying Darwinian selection. Such conditions are characteristic for populations after sympatric speciation. In conclusion, the middle part of chromosomes is more conserved and its structure seems to be responsible for belonging to higher taxons, while at the ends of chromosomes genes responsible for the intra species biodiversity are located.
关 键 词: 近亲繁殖; 遗传库; 基因组
课程来源: 视频讲座网
最后编审: 2019-03-19:lxf
阅读次数: 68