據(jù)4月10日的《科學(xué)》雜志報(bào)道,，科學(xué)家們在一項(xiàng)研究中說,，一組古老的綠藻具有令人詫異的基因多元性,，而這可能為人們提供綠色植物是如何進(jìn)化的線索。
Alexandra Worden及其同僚對兩株Micromonas海藻的基因組進(jìn)行了測序,。該海藻株是陸地植物的遠(yuǎn)古親緣植物,，它們存在于全世界各地的海洋中,。 文章的作者說，這些基因組揭露了這些遠(yuǎn)祖海藻所啟動(dòng)的數(shù)十億年的植物進(jìn)化和地球被綠化的軌跡特征,。 該國際研究團(tuán)隊(duì)發(fā)現(xiàn),，在這兩株海藻中存在著始料未及的遺傳變異水平，它們所遵循的是不同的進(jìn)化途徑,。
研究人員還發(fā)現(xiàn)了重要細(xì)胞器及細(xì)胞過程的標(biāo)志,，如基因沉默及硫胺的生物合成。 其中一株看來是獨(dú)特轉(zhuǎn)位因子的一個(gè)重要來源,，這種轉(zhuǎn)位因子過去在對Sargasso Sea的一個(gè)“宏基因組”的研究中曾被發(fā)現(xiàn),。 正如John Archibald在一篇相關(guān)的Perspective中所寫的，這些結(jié)果可幫助解釋為什么該基因“工具包”可能已經(jīng)存在于當(dāng)今陸地植物和綠藻的祖先植物之中,。（生物谷Bioon.com）
生物谷推薦原始出處：
Science 10 April 2009: DOI: 10.1126/science.1167222
Green Evolution and Dynamic Adaptations Revealed by Genomes of the Marine Picoeukaryotes Micromonas
Alexandra Z. Worden,1* Jae-Hyeok Lee,2 Thomas Mock,3 Pierre Rouzé,4 Melinda P. Simmons,1 Andrea L. Aerts,5 Andrew E. Allen,6 Marie L. Cuvelier,1,7 Evelyne Derelle,8 Meredith V. Everett,7 Elodie Foulon,9 Jane Grimwood,5,10 Heidrun Gundlach,11 Bernard Henrissat,12 Carolyn Napoli,13 Sarah M. McDonald,1 Micaela S. Parker,3 Stephane Rombauts,4 Aasf Salamov,5 Peter Von Dassow,9 Jonathan H. Badger,6 Pedro M. Coutinho,11 Elif Demir,1 Inna Dubchak,5 Chelle Gentemann,14 Wenche Eikrem,15 Jill E. Gready,16 Uwe John,17 William Lanier,18 Erika A. Lindquist,5 Susan Lucas,5 Klaus F. X. Mayer,10 Herve Moreau,8 Fabrice Not,9 Robert Otillar,5 Olivier Panaud,19 Jasmyn Pangilinan,5 Ian Paulsen,20 Benoit Piegu,19 Aaron Poliakov,5 Steven Robbens,4 Jeremy Schmutz,5,10 Eve Toulza,21 Tania Wyss,22 Alexander Zelensky,23 Kemin Zhou,5 E. Virginia Armbrust,3 Debashish Bhattacharya,18 Ursula W. Goodenough,2 Yves Van de Peer,4 Igor V. Grigoriev5
Picoeukaryotes are a taxonomically diverse group of organisms less than 2 micrometers in diameter. Photosynthetic marine picoeukaryotes in the genus Micromonas thrive in ecosystems ranging from tropical to polar and could serve as sentinel organisms for biogeochemical fluxes of modern oceans during climate change. These broadly distributed primary producers belong to an anciently diverged sister clade to land plants. Although Micromonas isolates have high 18S ribosomal RNA gene identity, we found that genomes from two isolates shared only 90% of their predicted genes. Their independent evolutionary paths were emphasized by distinct riboswitch arrangements as well as the discovery of intronic repeat elements in one isolate, and in metagenomic data, but not in other genomes. Divergence appears to have been facilitated by selection and acquisition processes that actively shape the repertoire of genes that are mutually exclusive between the two isolates differently than the core genes. Analyses of the Micromonas genomes offer valuable insights into ecological differentiation and the dynamic nature of early plant evolution.
1 Monterey Bay Aquarium Research Institute, Moss Landing, CA 95039 USA.
2 Department of Biology, Washington University at St. Louis, St. Louis, MO 63130, USA.
3 School of Oceanography, University of Washington, Seattle, WA 98195, USA.
4 Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB) and Department of Molecular Genetics, Ghent University, 9052 Gent, Belgium.
5 U.S. Department of Energy (DOE) Joint Genome Institute (JGI), Walnut Creek, CA 94598, USA.
6 J. Craig Venter Institute, San Diego, CA 92121, USA.
7 Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL 33149, USA.
8 Observatoire Océanologique, CNRS–Université Pierre et Marie Curie, 66651 Banyuls sur Mer, France.
9 Station Biologique de Roscoff, CNRS–Université Pierre et Marie Curie, Roscoff Cedex, France.
10 Stanford Human Genome Center, Stanford University School of Medicine, Palo Alto, CA 94304, USA.
11 Institute of Bioinformatics and System Biology, German Research Center for Environmental Health, 85764 Neuherberg, Germany.
12 Architecture et Fonction des Macromolécules Biologiques, Universities of Aix-Marseille I and II, Marseille 13288, France.
13 Biology Institute, University of Arizona, Tucson, AZ 85719, USA.
14 Remote Sensing Systems, Santa Rosa, CA 95401, USA.
15 Avdeling for Marinbiologi og Limnologi, University of Oslo, Oslo N-0316, Norway.
16 Division of Molecular Bioscience, College of Medicine, Biology and the Environment, Australian National University, Canberra ACT 2601, Australia.
17 Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen, Bremerhaven 27570, Germany.
18 Department of Biology, University of Iowa, Iowa City, IA 52242, USA.
19 Laboratoire Genome et Development des Plantes Université de Perpignan, 66860 Perpignan, France.
20 Department of Chemistry and Biomolecular Sciences, Macquarie University, New South Wales 2109, Australia.
21 Ecosystèmes Lagunaires, Université Montpellier II, F-34095 Montpellier Cedex 05, France.
22 Department of Biology, University of Miami, Miami, FL 33149, USA.
23 Department of Genetics, Erasmus Medical Center, Rotterdam 3015 CE, Netherlands.
