O impacto de transferência horizontal de gene de longa distância sobre o tamanho do genoma procariótico

The impact of long-distance horizontal gene transfer on prokaryotic genome size

Otto X. Cordero1 and Paulien Hogeweg

- Author Affiliations

Theoretical Biology and Bioinformatics, University of Utrecht, Padualaan 8 3584 CH, Utrecht, The Netherlands

Edited by James M. Tiedje, Michigan State University, East Lansing, MI, and approved October 30, 2009 (received for review July 11, 2009)

Abstract

Horizontal gene transfer (HGT) is one of the most dominant forces molding prokaryotic gene repertoires. These repertoires can be as small as ≈200 genes in intracellular organisms or as large as ≈9,000 genes in large, free-living bacteria. In this article we ask what is the impact of HGT from phylogenetically distant sources, relative to the size of the gene repertoire. Using different approaches for HGT detection and focusing on both cumulative and recent evolutionary histories, we find a surprising pattern of nonlinear enrichment of long-distance transfers in large genomes. Moreover, we find a strong positive correlation between the sizes of the donor and recipient genomes. Our results also show that distant horizontal transfers are biased toward those functional groups that are enriched in large genomes, showing that the trends in functional gene content and the impact of distant transfers are interdependent. These results highlight the intimate relationship between environmental and genomic complexity in microbes and suggest that an ecological, as opposed to phylogenetic, signal in gene content gains relative importance in large-genomed bacteria.

functional gene content microbial genomes scaling lateral gene transfer

Footnotes

1To whom correspondence should be sent at present address:

Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139.

E-mail: ottoxcordero@gmail.com

Author contributions: O.X.C. and P.H. designed research; O.X.C. performed research; O.X.C. analyzed data; and O.X.C. and P.H. wrote the paper.

The authors declare no conflict of interest.

This article is a PNAS Direct Submission.

This article contains supporting information online at www.pnas.org/cgi/content/full/0907584106/DCSupplemental.

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