Malmberg Russell L, Mauricio Rodney
Department of Plant Biology, University of Georgia, Athens, 30602-7271, USA.
Genet Res. 2005 Oct;86(2):89-95. doi: 10.1017/S0016672305007780.
The extent to which epistasis contributes to adaptation and speciation has been a controversial topic in evolutionary genetics. One experimental approach to study epistasis is based on quantitative trait locus (QTL) mapping using molecular markers. Comparisons can be made among all possible pair-wise combinations of the markers, irrespective of whether an additive QTL is associated with a marker; several software packages have been developed that facilitate this. We review several examples of using this approach to identify epistatic QTLs for traits of evolutionary or ecological interest. While there is variability in the results, the number of epistatic QTL interactions is often greater than or equal to the number of additive QTLs. The magnitude of epistatic effects can be larger than the additive effects. Thus, epistatic interactions seem to be an important part of natural genetic variation. Future studies of epistatic QTLs could lead to descriptions of the genetic networks underlying variation for fitness-related traits.
上位性在适应和物种形成过程中所起作用的程度，一直是进化遗传学中一个颇具争议的话题。一种研究上位性的实验方法是基于使用分子标记的数量性状位点（QTL）定位。可以对标记的所有可能两两组合进行比较，而不管加性QTL是否与某个标记相关联；已经开发了几个软件包来辅助进行此项工作。我们回顾了几个使用这种方法来鉴定与进化或生态相关性状的上位性QTL的例子。虽然结果存在差异，但上位性QTL相互作用的数量通常大于或等于加性QTL的数量。上位性效应的大小可能大于加性效应。因此，上位性相互作用似乎是自然遗传变异的一个重要组成部分。未来对上位性QTL的研究可能会揭示与适应性相关性状变异背后的遗传网络。
