Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Critical Care giúp cho các bạn có thêm kiến thức về ngành y học đề tài: The Opossum genome reveals further evidence for regulatory evolution in mammalian diversification. | Minireview The Opossum genome reveals further evidence for regulatory evolution in mammalian diversification Bernardo Lemos Address Department of Organismic and Evolutionary Biology Harvard University Divinity Avenue Cambridge MA 02138 USA. Email blemos@ Published 9 August 2007 Genome Biology 2007 8 223 doi gb-2007-8-8-223 The electronic version of this article is the complete one and can be found online at http 2007 8 8 223 2007 BioMed Central Ltd Abstract The sequencing of the euchromatic genome of a marsupial the opossum Monodelphis domestica identifies shared and unique features of marsupial and placental genomes and reveals a prominent role for the evolution of non-protein-coding elements. Mammalian diversification began approximately 250 million years ago yielding a stunning diversity of form and function that falls into three major groups with fundamentally distinct modes of reproduction. The monotremes Prototheria comprise a handful of extant species of egg-laying mammals the platypus and a few species of echidna. Placentals the Eutheria comprise about 4 500-5 000 species characterized by lengthy gestation with placental nourishment and neonates born at an advanced developmental stage and often nearly independent from the mother. Marsupials the Metatheria comprise about 250-300 species that are characterized by a rudimentary placenta and short gestation after which poorly developed embryos are born and undergo subsequent development during lactation usually inside the mother s marsupium or pouch. Marsupial and placental mammals diverged about 125-190 million years ago 1-3 . While the marsupial radiation stopped short of producing as many species as the placental one the impressive diversification of metatherians in South America and Australia resulted in a wide array of life histories and morphologies many of which matched those observed in placental mammals - from herbivores to insectivores to carnivores. Two of the
