A large cross section of microorganisms are found to be
haploid*
undergo
reproduction by asexual methods. Perhaps that could be the most appropriate logical explanation
that the concepts of the species, as it is widely applicable to the plant and animal kingdoms that
normally reproduce sexually and wherein the species may be stated precisely either in
genetic or in
evolutionary
terms, can never be made applicable very intimately and strictly to the microorganisms in
the right prespective. Importantly, the microbial species reasoning correctly can never be regarded as an
‘interbreeding population’
; and, therefore, the two ensuing offspring caused by the ultimate division
of a microbial cell are virtually quite ‘
free’ to develop in an altogether divergent fashion. It has been duly
observed that the reduction in genetic isolation caused by following
two recombination procedures,
namely:
(
a) Sexual or para sexual recombination, and
(
b) Special mechanisms of recombination.
usually offer great difficulty in assessing accurately the genuine effect of these recombination phenomena
by virtue of the fact that in nature the prevailing frequencies with which they take place remain to be
established. Nevertheless, in the domain of microorganisms, the problem of reduction in ‘
genetic isolation’
gets complicated by the legitimate presence of the
extrachromosomal** elements that specifically
help in the chromosomal rearrangements and transfers as well.
In the recent past, systematic and articulated attempts have been affected to characterize the
microbial species by carrying out the exhaustive descriptive studies of both
phenotype*** and genotype****.
Keeping in view the remarkable simplicity as observed in the structural variants in the microorganisms
these criteria or characteristics could not be used for their systematic classification on a sound
basis; and, therefore, one may resort to alternative characteristic features, namely: genetic, biochemical,
physiological, and ecological aspects in order to supplement the structural data authentically. Thus, one
may infer conclusively that the
bacterial classification is exclusively employed as a supporting evidencemore predominantly upon the functional attributes in comparison to the structural attributes.