Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogotá, Colombia.
Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow G12 8QQ, UK.
Microb Genom. 2022 Jun;8(6). doi: 10.1099/mgen.0.000843.
the causative agent of Chagas disease shows a marked genetic diversity and divided into at least six Discrete Typing Units (DTUs). High intra genetic variability has been observed in the TcI DTU, the most widely distributed DTU, where patterns of genomic diversity can provide information on ecological and evolutionary processes driving parasite population structure and genome organization. Chromosomal aneuploidies and rearrangements across multigene families represent an evidence of genome plasticity. We explored genomic diversity among 18 Colombian I clones and 15 . I South American strains. Our results confirm high genomic variability, heterozygosity and presence of a clade compatible with the TcI genotype, described for strains from humans in Colombia and Venezuela. TcI showed high structural plasticity across the geographical region studied. Differential events of whole and segmental aneuploidy (SA) along chromosomes even between clones from the same strain were found and corroborated by the depth and allelic frequency. We detected loss of heterozygosity (LOH) events in different chromosomes, however, the size and location of segments under LOH varied between clones. Genes adjacent to breakpoints were evaluated, and retrotransposon hot spot genes flanked the beginning of segmental aneuploidies. Our results suggest that genomes, like those of , may have a highly unstable structure and there is now an urgent need to design experiments to explore any potential adaptive role for the plasticity observed.
恰加斯病的病原体表现出明显的遗传多样性，可分为至少六个离散型单位（DTU）。在分布最广泛的 TcI DTU 中，观察到了高度的内部遗传变异性，基因组多样性模式可以提供有关驱动寄生虫种群结构和基因组组织的生态和进化过程的信息。多基因家族的染色体非整倍体和重排代表了基因组可塑性的证据。我们研究了来自哥伦比亚的 18 个 I 克隆和 15 个 I 南美株系之间的基因组多样性。我们的研究结果证实了高度的基因组变异性、杂合性以及与 TcI 基因型相容的分支的存在，这与来自哥伦比亚和委内瑞拉的人类菌株的描述一致。在研究的地理区域内，TcI 显示出高度的结构可塑性。在同一菌株的克隆之间甚至发现了整条和片段性非整倍体（SA）的全染色体和部分染色体的差异事件，并通过深度和等位基因频率得到了证实。我们检测到不同染色体上的杂合性丢失（LOH）事件，但 LOH 片段的大小和位置在克隆之间有所不同。评估了与断点相邻的基因，并且侧翼基因的反转录转座子热点基因在片段性非整倍体的开始处。我们的结果表明，与其他基因一样，基因组可能具有高度不稳定的结构，现在迫切需要设计实验来探索观察到的可塑性的任何潜在适应性作用。
