Mitochondrial DNAs provide insight into trypanosome phylogeny and molecular evolution.

IF 3.4 Q1 Agricultural and Biological Sciences
C Kay, T A Williams, W Gibson
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引用次数: 11

Abstract

Background: Trypanosomes are single-celled eukaryotic parasites characterised by the unique biology of their mitochondrial DNA. African livestock trypanosomes impose a major burden on agriculture across sub-Saharan Africa, but are poorly understood compared to those that cause sleeping sickness and Chagas disease in humans. Here we explore the potential of the maxicircle, a component of trypanosome mitochondrial DNA to study the evolutionary history of trypanosomes.

Results: We used long-read sequencing to completely assemble maxicircle mitochondrial DNA from four previously uncharacterized African trypanosomes, and leveraged these assemblies to scaffold and assemble a further 103 trypanosome maxicircle gene coding regions from published short-read data. While synteny was largely conserved, there were repeated, independent losses of Complex I genes. Comparison of pre-edited and non-edited genes revealed the impact of RNA editing on nucleotide composition, with non-edited genes approaching the limits of GC loss. African tsetse-transmitted trypanosomes showed high levels of RNA editing compared to other trypanosomes. The gene coding regions of maxicircle mitochondrial DNAs were used to construct time-resolved phylogenetic trees, revealing deep divergence events among isolates of the pathogens Trypanosoma brucei and T. congolense.

Conclusions: Our data represents a new resource for experimental and evolutionary analyses of trypanosome phylogeny, molecular evolution and function. Molecular clock analyses yielded a timescale for trypanosome evolution congruent with major biogeographical events in Africa and revealed the recent emergence of Trypanosoma brucei gambiense and T. equiperdum, major human and animal pathogens.

Abstract Image

Abstract Image

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线粒体dna提供了对锥虫系统发育和分子进化的深入了解。
背景:锥虫是单细胞真核寄生虫,其线粒体DNA具有独特的生物学特征。非洲牲畜锥虫对撒哈拉以南非洲的农业造成了重大负担,但与导致人类昏睡病和恰加斯病的锥虫相比,人们对其了解甚少。在这里,我们探讨了锥虫线粒体DNA的一个组成部分——最大环的潜力,以研究锥虫的进化史。结果:我们使用长读测序技术完全组装了来自4个以前未被鉴定的非洲锥虫的maxicycle线粒体DNA,并利用这些组装来支架和组装来自已发表的短读数据的另外103个锥虫maxicycle基因编码区。虽然synteny在很大程度上是保守的,但Complex I基因存在重复的、独立的损失。对预编辑和未编辑基因的比较揭示了RNA编辑对核苷酸组成的影响,未编辑基因接近GC损失的极限。与其他锥虫相比,非洲采采虫传播的锥虫表现出高水平的RNA编辑。利用大圆环线粒体dna基因编码区构建时间分辨系统进化树,揭示了布鲁氏锥虫和刚果锥虫分离株之间的深度分化事件。结论:我们的数据为锥虫的系统发育、分子进化和功能的实验和进化分析提供了新的资源。分子钟分析得出了与非洲主要生物地理事件一致的锥虫进化时间表,并揭示了最近出现的布氏冈比亚锥虫和装备锥虫这两种主要的人类和动物病原体。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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来源期刊
BMC Evolutionary Biology
BMC Evolutionary Biology 生物-进化生物学
CiteScore
5.80
自引率
0.00%
发文量
0
审稿时长
6 months
期刊介绍: BMC Evolutionary Biology is an open access, peer-reviewed journal that considers articles on all aspects of molecular and non-molecular evolution of all organisms, as well as phylogenetics and palaeontology.
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