Peek A S, Feldman R A, Lutz R A, Vrijenhoek R C
Center for Theoretical and Applied Genetics and Institute of Marine and Coastal Sciences, 71 Dudley Road, Rutgers University, New Brunswick, NJ 08901-8521, USA.
Proc Natl Acad Sci U S A. 1998 Aug 18;95(17):9962-6. doi: 10.1073/pnas.95.17.9962.
Vesicomyid clams depend entirely on sulfur-oxidizing endosymbiotic bacteria for their nutriment. Endosymbionts that are transmitted cytoplasmically through eggs, such as these, should exhibit a phylogenetic pattern that closely parallels the phylogeny of host mitochondrial genes. Such parallel patterns are rarely observed, however, because they are obscured easily by small amounts of horizontal symbiont transmission or occasional host switching. The present symbiont genealogy, based on bacterial small subunit (16S) rDNA sequences, was closely congruent with the host genealogy, based on clam mitochondrial cytochrome oxidase subunit I and large subunit (16S) rDNA sequences. This phylogenetic evidence supports the hypothesis of cospeciation and a long term association between the participants in this symbiosis.
囊蛤完全依赖硫氧化内共生细菌获取营养。像这样通过卵子进行细胞质遗传的内共生体,其系统发育模式应与宿主线粒体基因的系统发育密切平行。然而,这种平行模式很少被观察到,因为它们很容易被少量的水平共生体传播或偶尔的宿主转换所掩盖。基于细菌小亚基(16S)rDNA序列的当前共生体谱系,与基于蛤线粒体细胞色素氧化酶亚基I和大亚基(16S)rDNA序列的宿主谱系高度一致。这一系统发育证据支持了共物种形成假说以及这种共生关系中参与者之间的长期关联。