Gibson W C, Miles M A
EMBO J. 1986 Jun;5(6):1299-305. doi: 10.1002/j.1460-2075.1986.tb04359.x.
Little is known of the number or organization of chromosomes in Trypanosoma cruzi, the protozoan parasite responsible for Chagas' disease in man in the New World. Straightforward cytogenetic analysis is precluded because trypanosome chromosomes fail to condense during the cell cycle. We have size-fractionated the chromosome-sized DNA molecules of representative T. cruzi strains by pulsed field gradient (PFG) gel electrophoresis and located several housekeeping genes by Southern blotting using cDNA probes from the related trypanosome T. brucei. We show that DNA molecules from homologous chromosomes of T. cruzi migrate differently in the PFG system and infer that T. cruzi epimastigotes are at minimum diploid. In contrast to T. brucei, mini-chromosomes are absent in T. cruzi. All the housekeeping genes studied hybridize to DNA molecules which can be resolved in the PFG system, suggesting that T. cruzi may have no chromosomes larger than a few megabase pairs.
对于克氏锥虫（Trypanosoma cruzi）的染色体数量或组织结构，人们所知甚少。克氏锥虫是一种原生动物寄生虫，在新世界导致人类患恰加斯病（Chagas' disease）。由于锥虫染色体在细胞周期中无法浓缩，因此无法进行直接的细胞遗传学分析。我们通过脉冲场梯度（PFG）凝胶电泳对代表性克氏锥虫菌株的染色体大小的DNA分子进行了大小分级，并使用来自相关锥虫布氏锥虫（T. brucei）的cDNA探针通过Southern印迹法定位了几个管家基因。我们发现，克氏锥虫同源染色体的DNA分子在PFG系统中的迁移方式不同，并推断克氏锥虫前鞭毛体至少是二倍体。与布氏锥虫不同，克氏锥虫没有微型染色体。所有研究的管家基因都与可在PFG系统中分辨的DNA分子杂交，这表明克氏锥虫可能没有大于几兆碱基对的染色体。
