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#编者信息
熊荣川
明湖实验室
xiongrongchuan@126.com
http://blog.sciencenet.cn/u/Bearjazz
Reticulation Evolutionary processes commonly acting at the population level, such as recombination between genes and hybridization between lineages, and HOMOPLASY (Box 1), generate reticulate relationships within the population. Traditional methods, based on bifurcating trees, make no explicit allowance for such reticulations. Instead, for instance, maximum parsimony deals with ambiguities arising from homoplasy by simply selecting a tree that minimizes the number of assumptions of parallel, convergent or reversing mutations without showing where these might have occurred. Recombinants are also typically forced into a nonreticulating tree topology, in which, in some fortunate instances, they might occupy positions intermediate between two clusters. In other cases, the recombinant will be placed in a basal lineage to the clade that includes its most derived parent3,4.
| 网状结构 通常作用于群体层面的进化过程,如基因重组和谱系间的杂交以及异源同形(框注1),在群体内产生网状关系。传统的方法是基于分叉树,对这种网状结构没有明确的考虑。相反,例如,最大简约法通过简单地选择一棵树来处理由同形性引起的歧义,该树可以让并行、收敛或逆转突变的假设数量最小化,而不显示这些突变可能发生在哪里。重组子通常也被迫进入非连续的树拓扑结构,在某些幸运的情况下,它们可能占据两个集群之间的中间位置。在其他情况下,重组子将被置于包含其亲本的分支的基础谱系中。 |
Posada D , Crandall K A . Intraspecific gene genealogies: trees grafting into networks[J]. Trends in Ecology and Evolution, 2001, 16(1):0-45. |
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