Article

The bacterial species challenge: making sense of genetic and ecological diversity.

Department of Infectious Disease Epidemiology, Imperial College London, London W2 1PG, UK.
Science (impact factor: 31.2). 03/2009; 323(5915):741-6. DOI:10.1126/science.1159388
Source: PubMed

ABSTRACT The Bacteria and Archaea are the most genetically diverse superkingdoms of life, and techniques for exploring that diversity are only just becoming widespread. Taxonomists classify these organisms into species in much the same way as they classify eukaryotes, but differences in their biology-including horizontal gene transfer between distantly related taxa and variable rates of homologous recombination-mean that we still do not understand what a bacterial species is. This is not merely a semantic question; evolutionary theory should be able to explain why species exist at all levels of the tree of life, and we need to be able to define species for practical applications in industry, agriculture, and medicine. Recent studies have emphasized the need to combine genetic diversity and distinct ecology in an attempt to define species in a coherent and convincing fashion. The resulting data may help to discriminate among the many theories of prokaryotic species that have been produced to date.

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Keywords

bacterial species
 
biology-including horizontal gene transfer
 
coherent
 
convincing fashion
 
define species
 
distantly
 
distinct ecology
 
evolutionary theory
 
genetic diversity
 
genetically diverse superkingdoms
 
practical applications
 
prokaryotic species
 
Recent studies
 
resulting data
 
semantic question
 
variable rates