Effect of manipulating recombination rates on response to selection in livestock breeding programs.
Effect of manipulating recombination rates on response to selection in livestock breeding programs.
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DOI：
10.1186/s12711-016-0221-1
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发表时间：
2016-06-22
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影响因子：
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通讯作者：
Hickey JM
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作者：
Battagin M;Gorjanc G;Faux AM;Johnston SE;Hickey JM
在这项工作中，我们进行了模拟，以探索操纵重组率以增加牲畜育种计划中对选择的反应的潜力。我们对几种情况进行了10次重复，这些情况遵循共同的总体结构，但在基因组的平均重组率（表示为摩根染色体的长度）、选择下性状的遗传结构和截断选择下的选择强度（表示为被选择的雄性比例）方面存在差异。通过模拟9种不同的染色体长度来定义重组率：分别为0.10、0.25、0.50、1、2、5、10、15和20 Morgan。一个摩根被认为是目前家畜物种的典型染色体长度。遗传结构由影响选择性状的数量性状变异（QTV）的数量来定义。模拟了大量（10,000）或少量（1000或500）的QTV。截断选择的雄性后代比例分别为1.2、2.4、5%和10%。增加重组率提高了对选择的总体反应，减少了遗传变异的损失。低重组率和高重组率之间的累积反应差异随着世代的增加而增加。在低重组率下，对选择的累积反应倾向于更快地渐近线，遗传变异被完全侵蚀。当选择性状受较少QTV影响时，低重组率和高重组率之间仍存在差异，但在所有重组率下均达到选择极限。较高的重组率可以提高育种计划的效率，将遗传变异转化为对选择的反应。然而，为了显著提高对选择的响应，重组率需要提高10到20倍。重组率如此大幅度增加的生物学可行性和后果尚不清楚。本文的在线版本（doi:10.1186/s12711-016-0221-1）包含补充材料，可供授权用户使用。
In this work, we performed simulations to explore the potential of manipulating recombination rates to increase response to selection in livestock breeding programs. We carried out ten replicates of several scenarios that followed a common overall structure but differed in the average rate of recombination along the genome (expressed as the length of a chromosome in Morgan), the genetic architecture of the trait under selection, and the selection intensity under truncation selection (expressed as the proportion of males selected). Recombination rates were defined by simulating nine different chromosome lengths: 0.10, 0.25, 0.50, 1, 2, 5, 10, 15 and 20 Morgan, respectively. One Morgan was considered to be the typical chromosome length for current livestock species. The genetic architecture was defined by the number of quantitative trait variants (QTV) that affected the trait under selection. Either a large (10,000) or a small (1000 or 500) number of QTV was simulated. Finally, the proportions of males selected under truncation selection as sires for the next generation were equal to 1.2, 2.4, 5, or 10 %. Increasing recombination rate increased the overall response to selection and decreased the loss of genetic variance. The difference in cumulative response between low and high recombination rates increased over generations. At low recombination rates, cumulative response to selection tended to asymptote sooner and the genetic variance was completely eroded. If the trait under selection was affected by few QTV, differences between low and high recombination rates still existed, but the selection limit was reached at all rates of recombination. Higher recombination rates can enhance the efficiency of breeding programs to turn genetic variation into response to selection. However, to increase response to selection significantly, the recombination rate would need to be increased 10- or 20-fold. The biological feasibility and consequences of such large increases in recombination rates are unknown. The online version of this article (doi:10.1186/s12711-016-0221-1) contains supplementary material, which is available to authorized users.