Jaenike John, Dombeck Irene
Department of Biology, University of Rochester, Rochester, New York, 14627.
Evolution. 1998 Jun;52(3):832-840. doi: 10.1111/j.1558-5646.1998.tb03707.x.
The nematode Howardula aoronymphium parasitizes several species of mushroom-feeding Drosophila. A survey of isofemale strains of H. aoronymphium and a 25-generation selection experiment revealed that this species does not comprise host races, and that it harbors little heritable variation for adaptation to specific hosts No tradeoffs in performance on the different host species were evident. General-purpose genotypes, which can utilize all host species, characterize H. aoronymphium. An important feature of the natural history of these nematodes-correlated epidemiology across host species-is postulated to be both a cause and a consequence of the evolution of general-purpose genotypes in this species.
线虫霍华德杆线虫寄生于几种以蘑菇为食的果蝇物种。对霍华德杆线虫的同雌系菌株进行的一项调查以及一项25代的选择实验表明，该物种不包含宿主族，并且其适应特定宿主的可遗传变异很少。在不同宿主物种上的表现没有明显的权衡。能够利用所有宿主物种的通用基因型是霍华德杆线虫的特征。这些线虫自然史的一个重要特征——跨宿主物种的相关流行病学——被认为是该物种通用基因型进化的原因和结果。
