《美國(guó)科學(xué)院院刊》日前在線發(fā)表了中國(guó)科學(xué)院武漢植物園王恒昌博士和美國(guó)佛羅里達(dá)大學(xué)專(zhuān)家的合作研究成果，該成果揭示了顯花植物在爆發(fā)中分化,，并引發(fā)其它物種的適應(yīng)輻射。
據(jù)悉,，現(xiàn)存大約30萬(wàn)種的被子植物，分為約15,000屬和400多科,，而人類(lèi)理解這些類(lèi)群的親緣關(guān)系是一個(gè)艱巨的任務(wù),。該項(xiàng)研究通過(guò)多取樣、多基因的策略,，并采用基因序列同時(shí)比對(duì)可信化石記錄的方法開(kāi)展研究,。結(jié)果表明，現(xiàn)存約三十萬(wàn)種顯花植物中的1/3組成一個(gè)譜系,，即Rosids（薔薇類(lèi)）在9千萬(wàn)年前曾經(jīng)歷了一次爆發(fā)式分化,，同時(shí)又引發(fā)了兩棲類(lèi)、螞蟻,、哺乳動(dòng)物,、蕨類(lèi)等類(lèi)群的適應(yīng)輻射式物種形成。該研究利用現(xiàn)存生物的分子證據(jù),，首次揭示了這些植物的進(jìn)化關(guān)系,，為它們的快速形成和分化提供了依據(jù)。文章揭示出在一次爆發(fā)式分化中顯花植物的分化,，形成了以被子植物為主體的森林系統(tǒng),，這些森林系統(tǒng)后來(lái)成為了各種有機(jī)體的棲息地。研究結(jié)果對(duì)認(rèn)識(shí)地球上生物類(lèi)群間的親緣關(guān)系,，以及理解特定空間區(qū)域內(nèi)物種的相互競(jìng)爭(zhēng)關(guān)系也具有十分重要的指導(dǎo)意義,。（生物谷Bioon.com）
生物谷推薦原始出處：
PNAS February 17, 2009, doi: 10.1073/pnas.0813376106
Rosid radiation and the rapid rise of angiosperm-dominated forests
Hengchang Wanga,b, Michael J. Moorec, Pamela S. Soltisd, Charles D. Belle, Samuel F. Brockingtonb, Roolse Alexandreb, Charles C. Davisf, Maribeth Latvisb,f, Steven R. Manchesterd and Douglas E. Soltisb,1
aWuhan Botanical Garden, The Chinese Academy of Science, Wuhan, Hubei 430074 China;
bDepartment of Botany and
dFlorida Museum of Natural History, University of Florida, Gainesville, FL 32611;
cBiology Department, Oberlin College, Oberlin, OH 44074-1097;
eDepartment of Biological Sciences, University of New Orleans, New Orleans, LA 70148; and
fDepartment of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138
Abstract
The rosid clade (70,000 species) contains more than one-fourth of all angiosperm species and includes most lineages of extant temperate and tropical forest trees. Despite progress in elucidating relationships within the angiosperms, rosids remain the largest poorly resolved major clade; deep relationships within the rosids are particularly enigmatic. Based on parsimony and maximum likelihood (ML) analyses of separate and combined 12-gene (10 plastid genes, 2 nuclear; >18,000 bp) and plastid inverted repeat (IR; 24 genes and intervening spacers; >25,000 bp) datasets for >100 rosid species, we provide a greatly improved understanding of rosid phylogeny. Vitaceae are sister to all other rosids, which in turn form 2 large clades, each with a ML bootstrap value of 100%: (i) eurosids I (Fabidae) include the nitrogen-fixing clade, Celastrales, Huaceae, Zygophyllales, Malpighiales, and Oxalidales; and (ii) eurosids II (Malvidae) include Tapisciaceae, Brassicales, Malvales, Sapindales, Geraniales, Myrtales, Crossosomatales, and Picramniaceae. The rosid clade diversified rapidly into these major lineages, possibly over a period of <15 million years, and perhaps in as little as 4 to 5 million years. The timing of the inferred rapid radiation of rosids [108 to 91 million years ago (Mya) and 107–83 Mya for Fabidae and Malvidae, respectively] corresponds with the rapid rise of angiosperm-dominated forests and the concomitant diversification of other clades that inhabit these forests, including amphibians, ants, placental mammals, and ferns.
