Wallace D G, Maxson L R, Wilson A C
Proc Natl Acad Sci U S A. 1971 Dec;68(12):3127-9. doi: 10.1073/pnas.68.12.3127.
Frogs are an ancient group compared to placental mammals. Yet, although there are about as many species of frogs as there are of mammals, zoologists consider that frogs have undergone only limited morphological divergence, while placental mammals have diversified greatly in morphology and way of life. The serum albumins of numerous frog species were compared by the quantitative microcomplement fixation technique. Frogs that are morphologically similar enough to merit taxonomic distinction at only the species level often exhibit differences in the serological properties of their albumins larger than those usually seen between mammals placed in distinct families or suborders. Thus, there seems to be a contrast between albumin evolution and evolution at the organismal level. The large differences between albumins among frogs can be explained by the hypothesis that albumin evolution has proceeded at the same rate in frogs as in mammals.
与胎盘哺乳动物相比，青蛙是一个古老的类群。然而，尽管青蛙的物种数量与哺乳动物的大致相同，但动物学家认为青蛙仅经历了有限的形态分化，而胎盘哺乳动物在形态和生活方式上则有很大的多样性。通过定量微量补体结合技术对众多青蛙物种的血清白蛋白进行了比较。在形态上足够相似，仅在物种水平上才有分类学差异的青蛙，其白蛋白的血清学特性差异往往大于通常在不同科或亚目的哺乳动物之间所观察到的差异。因此，白蛋白进化与生物体水平的进化之间似乎存在差异。青蛙白蛋白之间的巨大差异可以用这样的假说来解释，即青蛙白蛋白的进化速度与哺乳动物相同。
