Shields G F, Wilson A C
J Mol Evol. 1987;24(3):212-7. doi: 10.1007/BF02111234.
Mitochondrial DNA was purified from five American species of geese representing the genera Anser and Branta, which have fossil records. The results of electrophoretic comparisons of about 75 fragments per individual produced by 14 restriction enzymes imply that the mean extent of sequence divergence between species of Anser and Branta is about 9%. Fossil evidence suggests that these two groups of geese had a common ancestor 4-5 million years ago. Thus, the mean rate of sequence divergence in goose mitochondrial DNA is not far from 2% per million years, the value in mammals.
从代表有化石记录的雁属和黑雁属的五种美洲鹅中纯化出线粒体DNA。用14种限制性酶对每个个体产生的约75个片段进行电泳比较的结果表明，雁属和黑雁属物种之间的平均序列差异程度约为9%。化石证据表明，这两组鹅在400万至500万年前有一个共同的祖先。因此，鹅线粒体DNA的平均序列差异率与哺乳动物的百万年2%的值相差不远。
