Reich Coralie M, Arnould John P Y
CRC for Innovative Dairy Products, Department of Zoology, University of Melbourne, Victoria 3010, Australia.
Biol Lett. 2007 Oct 22;3(5):546-9. doi: 10.1098/rsbl.2007.0265.
Despite the considerable variation in milk composition found among mammals, a constituent common across all groups is lactose, the main sugar and osmole in most eutherians milk. Exceptions to this are the families Otariidae (fur seals and sea lions) and Odobenidae (walruses), where lactose has not been detected. We investigated the molecular basis for this by cloning alpha-lactalbumin, the modifier protein of the lactose synthase complex. A mutation was observed which, in addition to preventing lactose production, may enable otariids to maintain lactation despite the extremely long inter-suckling intervals during the mother's time at sea foraging (more than 23 days in some species).
尽管在哺乳动物中发现的乳汁成分存在相当大的差异，但所有群体共有的一种成分是乳糖，它是大多数真兽类动物乳汁中的主要糖类和渗透溶质。海狗科（海狗和海狮）和海象科（海象）是例外，在它们的乳汁中未检测到乳糖。我们通过克隆乳糖合酶复合物的调节蛋白α-乳白蛋白来研究其分子基础。观察到一个突变，该突变除了阻止乳糖产生外，可能使海狗科动物尽管在母亲出海觅食期间（某些物种超过23天）存在极长的哺乳间隔，但仍能维持泌乳。
