Higo Hiroo, Miura Sachio, Horio Masahiro, Mimori Tatsuyuki, Hamano Shinjiro, Agatsuma Takeshi, Yanagi Tetsuo, Cruz-Reyes Arejandro, Uyema Norma, Rojas de Arias A, Matta Vivian, Akahane Hiroshige, Hirayama Kenji, Takeuchi Tsutomu, Tada Isao, Himeno Kunisuke
Department of Parasitology, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashiku, Fukuoka 812-8582, Japan.
Parasitol Int. 2004 Dec;53(4):337-44. doi: 10.1016/j.parint.2004.06.001.
Isozyme analysis with 18 enzyme loci was conducted on 146 isolates of Trypanosoma cruzi from Mexico, Guatemala, Colombia, Ecuador, Peru, Brazil, Bolivia, Paraguay and Chile. Forty-four different MLGs (groups of isolates with identical multilocus genotypes) were identified and a phylogeny was constructed. The phylogenetic tree consisted of two main groups (T. cruzi I, T. cruzi II), and the latter was further divided into two subgroups (T. cruzi IIa, T. cruzi IIb-e). Evidence of hybridization between different MLGs of T. cruzi II was found, which means that genetic exchanges seem to have occurred in South American T. cruzi. On the other hand, the persistence of characteristic T. cruzi I and T. cruzi II isozyme patterns in single small villages in Bolivia and Guatemala suggested that genetic exchange is very rare between major lineages. A significant difference in genetic diversity was shown between T. cruzi I and T. cruzi II from several indices of population genetics. Two possibilities could explain this genetic variation in the population: differences in evolutionary history and/or different tendencies to exchange genetic material. Broad-scale geographic distributions of T. cruzi I and T. cruzi IIb-e were different; T. cruzi I occurred in Central America and south to Bolivia and Brazil, while T. cruzi IIb-e occurred in the central and southern areas of South America, overlapping with T. cruzi I in Brazil and Bolivia.
对来自墨西哥、危地马拉、哥伦比亚、厄瓜多尔、秘鲁、巴西、玻利维亚、巴拉圭和智利的146株克氏锥虫分离株进行了18个酶位点的同工酶分析。鉴定出44种不同的多基因座基因型组合（具有相同多位点基因型的分离株组）并构建了系统发育树。系统发育树由两个主要组（克氏锥虫I、克氏锥虫II）组成，后者进一步分为两个亚组（克氏锥虫IIa、克氏锥虫IIb - e）。发现了克氏锥虫II不同多基因座基因型组合之间杂交的证据，这意味着南美克氏锥虫似乎发生了基因交换。另一方面，在玻利维亚和危地马拉的单个小村庄中，克氏锥虫I和克氏锥虫II特征性同工酶模式的持续存在表明主要谱系之间的基因交换非常罕见。从几个群体遗传学指标来看，克氏锥虫I和克氏锥虫II之间的遗传多样性存在显著差异。有两种可能性可以解释种群中的这种遗传变异：进化历史的差异和/或交换遗传物质的不同倾向。克氏锥虫I和克氏锥虫IIb - e的广泛地理分布不同；克氏锥虫I分布在中美洲以及南至玻利维亚和巴西，而克氏锥虫IIb - e分布在南美洲的中部和南部地区，在巴西和玻利维亚与克氏锥虫I重叠。
