Henriksson J, Aslund L, Macina R A, Franke de Cazzulo B M, Cazzulo J J, Frasch A C, Pettersson U
Department of Medical Genetics, Uppsala University, Sweden.
Mol Biochem Parasitol. 1990 Sep-Oct;42(2):213-23. doi: 10.1016/0166-6851(90)90164-h.
The karyotype of Trypanosoma cruzi was studied by pulsed field gel electrophoresis (PFGE) in conditions that allowed 20-25 chromosome bands to be detected. However, several of these bands were present in non-equimolar amounts, suggesting that the total chromosome number is considerably higher. The patterns obtained with the different cloned and uncloned strains were unique, suggesting that the karyotype of T. cruzi is highly variable. The chromosomal localizations of seven cloned genes were determined by Southern blotting of PFGE-separated chromosomes. Three of the clones gave rise to similar patterns and mapped on a chromosome or a family of chromosomes larger than 1.6 Mb. Two clones mapped on either single or pairs of chromosomes, which in some cases differed considerably in size between the different strains tested, suggesting that extensive chromosome rearrangements occur in T. cruzi. Another clone hybridized to several chromosomes in most strains and probably represents a family of genes. Lastly, one clone hybridized to nearly all chromosomes. Many of the clones hybridized to pairs of restriction fragments in the different strains, suggesting that they are allelic. For one of the clones it was possible to provide further evidence for the allelic nature of the fragments by establishing detailed restriction maps around them and by showing that the two fragments in a pair hybridized to chromosomes which differed slightly in size. Taken together, the results infer that the genome of T. cruzi epimastigotes is diploid.
通过脉冲场凝胶电泳（PFGE）在能检测到20 - 25条染色体条带的条件下研究了克氏锥虫的核型。然而，这些条带中有几条的含量并非等摩尔，这表明染色体总数要高得多。用不同的克隆和未克隆菌株获得的图谱是独特的，这表明克氏锥虫的核型高度可变。通过对PFGE分离的染色体进行Southern印迹分析，确定了7个克隆基因的染色体定位。其中三个克隆产生相似的图谱，并定位在大于1.6 Mb的一条染色体或一组染色体上。两个克隆定位在单条或成对的染色体上，在某些情况下，不同测试菌株的这些染色体大小差异很大，这表明克氏锥虫中发生了广泛的染色体重排。另一个克隆在大多数菌株中与几条染色体杂交，可能代表一个基因家族。最后一个克隆与几乎所有染色体杂交。许多克隆在不同菌株中与成对的限制性片段杂交，表明它们是等位基因。对于其中一个克隆，通过在其周围建立详细的限制性图谱，并表明一对中的两个片段与大小略有不同的染色体杂交，有可能为这些片段的等位基因性质提供进一步的证据。综合来看，结果推断克氏锥虫前鞭毛体的基因组是二倍体。
