SELECTIVE MECHANISMS IN BACTERIA

Abstract

The objective in population genetics is to reconstruct the possible, or more rarely the actual, sequence of events in the evolution of organisms in terms of changes resulting from the interplay of mutation and selection. The possibility of entirely succeeding in this is of course dependent on a valid and complete assessment of the attributes of the genetic systems involved. Failing in this, we may empirically examine the genetic constitution of populations before specifying any precise basis for the variability observed. The non-sexual bacteria offer good opportunities along these lines, because the immediate source of genetic variability resides in the capacity of the existing genotype to mutate, and not in the emergence of recombinant types. In other words, the reservoir of variability is not concealed, but is directly represented by the components of heterogeneous populations.