# name
Population Genetics of the Aeromonas hydrophila Species Complex

# metadata.dc.description.abstract[].value
Population genetics studies the genetic variability of individuals in a population based on
the allele frequencies at several genes or loci and tries to explain this variability in terms of
mutation, selection or genetic recombination. The statistical analysis of these frequencies
allows models of evolution to be established, which will help us to understand and predict
the past and present gene flow in the population (Maynard-Smith, 1991). For the most part
population genetics has been designed for diploid organisms with sexual reproduction. In
the words of Bruce Levin, “the genetic theory of adaptive evolution was developed by
sexually reproducing eukaryotes, for sexually reproducing eukaryotes” (Levin & Bergstrom,
2000). As a consequence, before being applied to prokaryotes, population genetics needs to
be adapted.
In theory the haploid nature of bacteria should simplify their analysis, since dominance or
over-dominance is not an issue and the genotype can usually be deduced directly from the
phenotype. However, central to classical population genetics are infinite population size,
random mating, and free recombination. Consequently, as expressed by Maynard-Smith,
“the alleles present at one locus are independent of those at other loci. Changes in the
frequency of an allele at one locus, therefore, are independent of what is happening
elsewhere in the genome: each locus can be treated individually” (Maynard-Smith, 1995). It
is true that the size of bacterial populations can be practically infinite but recombination
occurs extremely rarely so that changes affecting one locus can lead to the modification of
others. In the succinct words of Maynard-Smith, “the genome should be treated as an interrelated
whole, and not as a set of independently changing genes”. The crux of the problem is
knowing the exact level of recombination in bacterial populations, since “it is considerably
more challenging to elaborate a theory for a population with little recombination than for
one with no recombination, or a lot” (Maynard-Smith, 1995). In bacterial population
genetics, sometimes we detect a degree of recombination that is too high for a pure
phylogenetic approach, but too low for assessing a random interchange...

# metadata.dc.rights[].value
cc by (c) Fusté Munné, M. Carme et al., 2012

# metadata.dc.source[].value
Articles publicats en revistes (Biologia, Sanitat i Medi Ambient)

# metadata.dc.title[].value
Population Genetics of the Aeromonas hydrophila Species Complex