The Evolution of Molecular Parasites: The Importance of Geonomic Context

分子寄生虫，如转座元件，是DNA片段，整合到染色体中并增殖，在基因组内高度重复。这种增殖通常对基因组有害，并产生强大的选择压力来对抗它们的活动。在真菌中，一种基因组防御机制(“重复诱导点突变”)改变了分子寄生虫的DNA序列，从而破坏了它们的增殖能力。经验和理论研究将调查分子寄生虫的进化，因为它们似乎与宿主基因组进行军备竞赛，以逃避其防御机制。分子寄生虫是几乎所有生物基因组中极具影响力的组成部分，对基因组大小、突变率、DNA结构和交配系统等基本特征都有影响。分子寄生虫的活性也与许多人类遗传性疾病和染色体重排有关。因此，研究哪些因素限制了分子寄生虫的进化，将促进我们对基因组结构和对遗传稳定性的特别威胁的理解。这项研究还具有广泛的理论意义，因为它解决了基于DNA的寄生的独特性质，允许分子寄生虫和它们居住的基因组之间的共同进化。

Molecular parasites, such as transposable elements, are segments of DNA that integrate into chromosomes and proliferate to become highly repetitive within the genome. This proliferation is often harmful to the genome and creates strong selection pressure to counter their activity. In the fungus Microbotryum violaceum a genomic defense mechanism ("repeat-induced point mutations") acts to change the DNA sequence of molecular parasites thus destroying their ability to proliferate. Empirical and theoretical studies will investigate the evolution of molecular parasites as they appear to engage in an arms race with the host genome in order to elude its defensive mechanisms. Molecular parasites are highly influential components of the genomes of nearly all organisms, with effects upon such fundamental traits as genome size, mutation rates, DNA structure, and mating systems. The activity of molecular parasites has also been implicated in many human-inherited diseases and chromosome rearrangements. Therefore, investigation into which factors limit the evolution of molecular parasites will advance our understanding of genome structure and of particular threats to genetic stability. This research also has broad theoretical implications because it addresses the unique nature of DNA-based parasitism that allows for co-evolution between the molecular parasites and the genomes they inhabit.