van Oppen M J, Willis B L, Miller D J
Department of Biochemistry and Molecular Biology, James Cook University, Townsville, Australia.
Proc Biol Sci. 1999 Jan 22;266(1415):179-83. doi: 10.1098/rspb.1999.0619.
Unexpectedly low levels of mitochondrial DNA (mtDNA) cytochrome b sequence divergence are found between species of the scleractinian coral genus Acropora. Comparison of 964 positions of the cytochrome b gene of two out of the three Caribbean Acropora species with seven of their Pacific congeners shows only 0.3-0.8% sequence difference. Species in these biogeographic regions have been evolving independently for at least three million years (since the rise of the Isthmus of Panama) and this geological date is used to estimate nucleotide divergence rates. The results indicate that the Acropora cytochrome b gene is evolving at least 10-20 times slower than the 'standard' vertebrate mtDNA clock and is one of the most slowly evolving animal mitochondrial genes described to date. The possibility is discussed that, unlike higher animals, cnidarians may have a functional mtDNA mismatch repair system.
在鹿角珊瑚属的石珊瑚物种之间，发现线粒体DNA（mtDNA）细胞色素b序列差异水平出乎意料地低。对三种加勒比鹿角珊瑚物种中的两种及其七种太平洋同属物种的细胞色素b基因的964个位置进行比较，结果显示序列差异仅为0.3 - 0.8%。这些生物地理区域的物种至少已经独立进化了300万年（自巴拿马地峡隆起以来），并且这个地质年代被用于估计核苷酸差异率。结果表明，鹿角珊瑚的细胞色素b基因的进化速度比“标准”脊椎动物线粒体DNA时钟慢至少10 - 20倍，并且是迄今为止所描述的进化最慢的动物线粒体基因之一。文章讨论了一种可能性，即与高等动物不同，刺胞动物可能具有功能性的线粒体DNA错配修复系统。
