Pineda-Krch M, Lehtilä K
Department of Zoology, 6270 University Boulevard, University of British Columbia, Vancouver, BC, Canada.
J Evol Biol. 2004 Nov;17(6):1167-77. doi: 10.1111/j.1420-9101.2004.00808.x.
An increasing number of studies have recently detected within-organism genetic heterogeneity suggesting that genetically homogeneous organisms may be rare. In this review, we examine the potential costs and benefits of such intraorganismal genetic heterogeneity (IGH) on the fitness of the individual. The costs of IGH include cancerous growth, parasitism, competitive interactions and developmental instability, all of which threaten the integrity of the individual while the potential benefits are increased genetic variability, size-specific processes, and synergistic interactions between genetic variants. The particular cost or benefit of IGH in a specific case depends on the organism type and the origin of the IGH. While mosaicism easily arise by genetic changes in an individual, and will be the more common type of IGH, chimerism originates by the fusion of genetically distinct entities, and is expected to be substantially rare in most organisms. Potential conflicts and synergistic effects between different genetic lineages within an individual provide an interesting example for theoretical and empirical studies of multilevel selection.
最近，越来越多的研究在生物体内检测到遗传异质性，这表明基因同质的生物体可能很罕见。在这篇综述中，我们研究了这种生物体内遗传异质性（IGH）对个体适应性的潜在成本和益处。IGH的成本包括癌性生长、寄生、竞争相互作用和发育不稳定性，所有这些都会威胁个体的完整性，而潜在益处则是增加遗传变异性、特定大小的过程以及遗传变异之间的协同相互作用。IGH在特定情况下的具体成本或益处取决于生物体类型和IGH的起源。虽然镶嵌现象很容易因个体的基因变化而出现，并且将是IGH更常见的类型，但嵌合体是由基因不同的实体融合产生的，预计在大多数生物体中非常罕见。个体内不同遗传谱系之间的潜在冲突和协同效应为多层次选择的理论和实证研究提供了一个有趣的例子。
