Beauchamp K A, Powers D A
Department of Biological Sciences, Hopkins Marine Station, Stanford University, Pacific Grove, California 93950, USA.
Mol Mar Biol Biotechnol. 1996 Dec;5(4):357-62.
Interspecific and intraspecific variation in the first internal transcribed spacer region (ITS-1) of ribosomal DNA (rDNA) was examined in two species of ahermatypic corals (lacking symbiotic algae and non-reef-building) with different dispersal characteristics, Paracyathus stearnsii (gamete-spawner with pelagic larvae) and Balanophyllia elegans (brooder with benthic larvae) from California. An approximately 300-bp region of the ITS-1 was amplified by polymerase chain reaction (PCR) and sequenced from populations at Pt. Loma, La Jolla, Monterey Bay, and Santa Catalina Island and compared for each species and compared with the same region from the hermatypic coral Favia lizardensis. There was a wide range of sequence variation in the ITS-1 region between the species, and these differences readily distinguished the taxa. Intraspecific comparisons of P. stearnsii individuals showed very little sequence variation (two polymorphisms) in the ITS-1 region. In contrast to P. stearnsii, we found 14 variable nucleotide sties in the ITS-1 region for B. elegans. Although there were no nucleotide sites that diagnostically separated central and southern populations, these findings indicate that the ITS-1 region is variable in B. elegans and a promising source for nuclear molecular markers in ahermatypic corals.
研究人员对来自加利福尼亚的两种非造礁珊瑚（缺乏共生藻类且不形成珊瑚礁）——硬星珊瑚（Paracyathus stearnsii，配子产卵者，具浮游幼虫）和秀丽柱星珊瑚（Balanophyllia elegans，育幼者，具底栖幼虫）——核糖体DNA（rDNA）的第一内部转录间隔区（ITS-1）的种间和种内变异进行了检测。通过聚合酶链反应（PCR）扩增了ITS-1约300 bp的区域，并对洛马角、拉霍亚、蒙特雷湾和圣卡塔利娜岛种群的该区域进行了测序，对每个物种进行了比较，并与造礁珊瑚蜥蜴蜂巢珊瑚（Favia lizardensis）的相同区域进行了比较。物种间ITS-1区域存在广泛的序列变异，这些差异很容易区分分类单元。硬星珊瑚个体的种内比较显示，ITS-1区域的序列变异非常小（两个多态性）。与硬星珊瑚相反，我们在秀丽柱星珊瑚的ITS-1区域发现了14个可变核苷酸位点。虽然没有核苷酸位点能在诊断上区分中部和南部种群，但这些发现表明，ITS-1区域在秀丽柱星珊瑚中是可变的，是一种有前景的非造礁珊瑚核分子标记来源。
