Difficulties Encountered in Classification of Microorganisms

Difficulties Encountered in Classification of Microorganisms

A large cross section of microorganisms are found to be haploid* in nature, and they invariably undergo reproduction by asexual methods. Perhaps that could be the most appropriate logical explana-tion 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 phenom-ena 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 isola-tion’ gets complicated by the legitimate presence of the extrachromosomal** elements that specifi-cally 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 geno-type****. Keeping in view the remarkable simplicity as observed in the structural variants in the micro-organisms 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 evi-dence more predominantly upon the functional attributes in comparison to the structural attributes.