Reconstrução de protocromossomos monocotelidôneos revela: evolução mais rápida nas plantas do que em animais

Reconstruction of monocotelydoneous proto-chromosomes reveals faster evolution in plants than in animals

Jérôme Salsea,1, Michael Abrouka, Stéphanie Bolota, Nicolas Guilhota, Emmanuel Courcelleb, Thomas Farautc, Robbie Waughd, Timothy J. Closee, Joachim Messingf and Catherine Feuilleta

+ Author Affiliations

aInstitut National de la Recherche Agronomique, Unité Mixte de Recherche 1095, Génétique, Diversité et Ecophysiologie des Céréales, Université Blaise Pascal, 234 Avenue du Brézet, 63100 Clermont Ferrand, France;

bInstitut National de la Recherche Agronomique, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 441/2594, Laboratoire des Interactions Plantes-Microorganismes, 31326 Castanet Tolosan, France;

cInstitut National de la Recherche Agronomique Unité Mixte de Recherche 444, BP 52627, 31326 Castanet Tolosan, France;

dScottish Crop Research Institute, Invergowrie, Dundee, DD2 5DA, Scotland, United Kingdom;

eDepartment of Botany and Plant Sciences, 2150 Batchelor Hall, University of California, Riverside, CA 92521-0124; and

fThe Plant Genome Initiative at Rutgers, Waksman Institute, Piscataway, NJ 08854

Abstract

Paleogenomics seeks to reconstruct ancestral genomes from the genes of today's species. The characterization of paleo-duplications represented by 11,737 orthologs and 4,382 paralogs identified in five species belonging to three of the agronomically most important subfamilies of grasses, that is, Ehrhartoideae (rice) Panicoideae (sorghum, maize), and Pooideae (wheat, barley), permitted us to propose a model for an ancestral genome with a minimal size of 33.6 Mb structured in five proto-chromosomes containing at least 9,138 predicted proto-genes. It appears that only our major evolutionary shuffling events (α, β, γ, and δ) explain the divergence of these five cereal genomes during their evolution from a common paleo-ancestor. Comparative analysis of ancestral gene function with rice as a reference indicated that five categories of genes were preferentially modified during evolution. Furthermore, alignments between the five grass proto-chromosomes and the recently identified seven eudicot proto-chromosomes indicated that additional very active episodes of genome rearrangements and gene mobility occurred during angiosperm evolution. If one compares the pace of primate evolution of 90 million years (233 species) to 60 million years of the Poaceae (10,000 species), change in chromosome structure through speciation has accelerated significantly in plants.

grasses paleogenomics

Footnotes

1To whom correspondence should be addressed at: INRA/UBP UMR GDEC 1095, Domaine de Crouelle, 234 Avenue du Brézet 63100 Clermont Ferrand, France. E-mail: jsalse@clermont.inra.fr

Author contributions: J.S. designed research; J.S., M.A., and S.B. performed research; N.G., E.C., T.F., R.W., T.J.C., and J.M. contributed new reagents/analytic tools; J.S., M.A., and S.B. analyzed data; and J.S. and C.F. wrote the paper.

Edited by Eviatar Nevo, Institute of Evolution, Haifa, Israel, and approved June 30, 2009

The authors declare no conflict of interest.

This article is a PNAS Direct Submission.

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