Effect of coinheritance on host-pathogen coevolution

描述（由申请人提供）：拟议研究的总体目标是发展必要的遗传学理论，以了解宿主和微生物基因组的共同传播模式如何影响共生细菌和致病菌与宿主的共同进化。我们的方法是新颖的，因为它扩展了为单基因组内核基因组合遗传建模的理论，以跨两个基因组（宿主和病原体的基因组）的基因组合。当应用于细胞核和线粒体基因组合时，该方法成功地预测了功能基因从线粒体转移到细胞核的频率：功能基因的基因组间转移在近交物种中发生的可能性是异交物种的十倍。交配系统对基因转移产生这种影响的原因是，与基因独立遗传的交配系统相比，线粒体和核基因一起遗传的交配系统允许自然选择更有效地作用于基因组合。虽然线粒体像一些内共生体一样完全垂直传播，但在只有部分垂直传播的系统中预计也会出现类似的效果，我们将发展这一更普遍的理论。双位点遗传理论量化了相同或不同基因组中基因组合的共遗传，确定了每个物种中基因进化轨迹的结合程度。这决定了宿主-病原体关联是否会朝着增强毒力或良性共生的方向发展。

DESCRIPTION (provided by applicant): The overall goal of the proposed research is to develop the genetic theory necessary for understanding how patterns of co-transmission of host and microbial genomes affect the co-evolution of symbiotic and pathogenic bacteria with their hosts. Our approach is novel in that it extends theory developed for modeling the inheritance of nuclear gene combinations within single genomes to gene combinations across two genomes, those of host and pathogen. When applied to nuclear and mitochondrial gene combinations, this approach successfully predicted the frequency of functional gene transfer from the mitochondria to the nucleus: inter-genomic transfer of functional genes is ten-fold more likely to occur in inbreeding species than in outcrossing species. The reason for this effect of mating system on gene transfer is that mating systems, where mitochondrial and nuclear genes are inherited together, allow natural selection to act more effectively on gene combinations than mating systems where the genes are inherited independently. Although mitochondria are wholly vertically transmitted like some endosymbionts, similar effects are expected to be manifest in systems with only partial vertical transmission and we will develop this more general theory. Two-locus descent theory quantifies the coinheritance of gene combinations in the same or different genomes, determining the degree to which the evolutionary trajectories of genes in each species are conjoined. This determines whether a host-pathogen association will develop toward enhanced virulence or toward benign symbiosis. Project Narrative: Change in the dispersal rates fundamentally change the genetic coevolution both hosts and their pathogens and contribute to the emergence of new diseases. Although a direct link between dispersal of infected hosts and disease epidemiology within a single host generation is well known, the genetic consequences of disease transmission from one generation of hosts to the next is much more poorly understood. This proposal will develop genetic theory for addressing how the co-inheritance of host genes and host pathogens affects the evolution of disease virulence.