Patterns of recombination and MLH1 foci density along mouse chromosomes:: Modeling effects of interference and obligate chiasma
Patterns of recombination and MLH1 foci density along mouse chromosomes:: Modeling effects of interference and obligate chiasma
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DOI：
10.1534/genetics.106.070235
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发表时间：
2007-07-01
期刊：
影响因子：
3.3
通讯作者：
Martin, O. C.
中科院分区：
文献类型：
--
作者：
Falque, M.;Mercier, R.;Martin, O. C.
减数分裂中的交叉干扰通常通过平稳更新过程来建模。在这里，我们考虑一个新模型来结合已知的“专性交叉”生物学特征，即在大多数生物体中，每个二价体几乎总是至少有一个交叉。初始交叉被建模为均匀分布沿着染色体，并从它的位置开始，随后的交叉放置与前向和后向固定更新过程使用卡方分布的交叉距离。我们使用我们的模型以及标准卡方模型来模拟交叉密度的模式沿着二价体或染色单体，对于那些有零，一个，两个，或三个或更多的交叉;事实上，这种模式取决于交叉的数量。在这两种模型中，模拟的模式与在小鼠中实验发现的模式相比非常好，无论是对于二价体上的MLH 1病灶还是对于遗传图谱上的交叉。然而，与标准卡方模型相比，我们的模型提供了更好的实验数据拟合，特别是关于每条染色体的交叉数量的分布。最后，我们的模型预测增强的重组率附近的四肢，然而，这只能解释在小鼠中观察到的模式的一部分。
Crossover interference in meiosis is often modeled via stationary renewal processes. Here we consider a new model to incorporate the known biological feature of "obligate chiasma" whereby in most organisms each bivalent almost always has at least one crossover. The initial crossover is modeled as uniformly distributed along the chromosome, and starting from its position, subsequent crossovers are placed with forward and backward stationary renewal processes using a chi-square distribution of intercrossover distances. We used Our model as well as the standard chi-square model to simulate the patterns of crossover densities along bivalents or chromatids for those having zero, one, two, or three or more crossovers; indeed, such patterns depend on the number of crossovers. With both models, Simulated patterns compare very well to those found experimentally in mice, both for MLH1 foci on bivalents and for crossovers on genetic maps. However, our model provides a better fit to experimental data as compared to the standard chi-square model, particularly regarding the distribution of numbers of crossovers per chromosome. Finally, our model predicts an enhancement of the recombination rate near the extremities, which, however, explains only a part of the pattern observed in mouse.