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Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: The origin and evolution of lactation. | Journal of Biology BioMed Central Minireview The origin and evolution of lactation Anthony V Capuco and R Michael Akers1 Addresses USDA-ARS Bovine Functional Genomics Laboratory Powder Mill BARC-East Beltsville MD 20705 USA. Virginia Polytechnic Institute and State University Department of Dairy Science 2470 Litton-Reaves Hall Blacksburg VA 24061 USA. Correspondence Anthony V Capuco. Email tony.capuco@ars.usda.gov Published 24 April 2009 Journal of Biology 2009 8 37 doi 10.1186 jbiol139 The electronic version of this article is the complete one and can be found online at http jbiol.com content 8 4 37 2009 BioMed Central Ltd Abstract The presence of mammary glands is the defining morphological feature of mammals. The recent assembly of the bovine genome and a report in Genome Biology that links the milk and lactation data of bovine and other mammalian genomes will help biologists investigate this economically and medically important feature. The mammary gland has been a pivotal feature in the evolution and taxonomic classification of animal species and it has even had a role in the acceptance of evolutionary theory. The presence and secretory capacity of the mammary gland provided the basis for the taxonomic grouping of species into the class Mammalia more than two centuries ago and Darwin s explanation of how lactation may have evolved satisfied an early challenge to his theory of evolution by natural selection 1 . The challenge was that evolution of lactation was not feasible because a neonate could not obtain a survival benefit from consuming the chance secretion of a rudimentary cutaneous gland. In response Darwin hypothesized that mammary glands evolved from cutaneous glands that were contained within the brood pouches in which some fish and other marine species keep their eggs and provided nourishment and thus a survival advantage to eggs of ancestral species. Two hundred years after Darwin s birth the theory of evolution by natural selection remains a .
