显然，这种逆转录病毒基因填补了哺乳动物生物学的一个小生境，但是从另一方面来说，在第一次感染此类病毒以前，哺乳动物已经能够完美的生殖了。
Clearly, this retroviral gene fills an important niche in mammalian biology, but, on the other hand, mammals were able to reproduce perfectly well before they were first infected.
这是《哺乳动物生物学》杂志的网页。
“老鼠是比鸟更好的实验材料，因为它们是哺乳动物，并且它们的大脑结构和其它生物学特征和人类的更相近，”内村说。
"Mice are better than birds to study because they are mammals and much closer to humans in their brain structures and other biological aspects," Uchimura said.
应用推荐