Yasue H, Wada Y
Animal Genome Research Group, National Institute of Animal Industry, Ibaraki, Japan.
Anim Genet. 1996 Apr;27(2):95-8. doi: 10.1111/j.1365-2052.1996.tb00474.x.
The distribution of PRE-1 sequence (a swine SINE) among the animal species related to Sus scrofa, i.e. Phacochoerus aethiopicus and Tayassu tajacu, was examined by dot-blot analysis using PRE-1 sequences as a probe. This revealed that Phacochoerus aethiopicus and Tayassu tajacu contained PRE-1 sequences, amounts of which in their genomes are almost the same as that in the swine genome, indicating that these species separated after PRE-1 sequences proliferated to diversify in the genome. In order to estimate the time when the PRE-1 started to diversify in the swine genome, PRE-1 sequences were extracted from GenBank DNA database by homology analysis using the PRE-1 consensus sequence as a probe. The 22 PRE-1 sequences obtained were aligned and their phylogenetic relation was calculated by the neighbour-joining method. The result of the calculation combined with the mutation rate of the pseudogenes (r = 4.6 x 10(-9)) indicated that the PRE-1 sequence diversified at least 43.2 million years ago. Taken together, the period of time since the separation of the three species, Sus scrofa, Phacochoerus aethiopicus and Tayassu tajacu, is currently estimated to be less than 43.2 million years.
使用PRE - 1序列作为探针，通过斑点杂交分析检测了PRE - 1序列（一种猪短散在重复元件）在与野猪（Sus scrofa）相关的动物物种，即埃塞俄比亚疣猪（Phacochoerus aethiopicus）和草原西貒（Tayassu tajacu）中的分布情况。结果显示，埃塞俄比亚疣猪和草原西貒含有PRE - 1序列，其基因组中的PRE - 1序列数量与猪基因组中的几乎相同，这表明这些物种在PRE - 1序列在基因组中增殖并多样化之后才发生分化。为了估计PRE - 1在猪基因组中开始多样化的时间，使用PRE - 1共有序列作为探针，通过同源性分析从GenBank DNA数据库中提取PRE - 1序列。对获得的22个PRE - 1序列进行比对，并通过邻接法计算它们的系统发育关系。计算结果与假基因的突变率（r = 4.6 x 10(-9)）相结合，表明PRE - 1序列至少在4320万年前就已经多样化。综上所述，目前估计野猪、埃塞俄比亚疣猪和草原西貒这三个物种分化以来的时间不到4320万年。
