1. A computer implemented method for pre-tagging a subset of reference clusters from amongst a plurality of reference clusters as probable rDNA clusters and using information obtained by pre-tagging for identification of ribosomal deoxyribonucleic acid (rDNA) sequences from a sample containing a plurality of unknown DNA sequences, the method comprising: obtaining a plurality of reference sequences from a reference database; creating said plurality of reference clusters using said plurality of reference sequences; performing a rDNA analysis to pre-tag said subset of reference clusters, from amongst the plurality of reference clusters, as the probable rDNA clusters, wherein the rDNA analysis comprises: obtaining a plurality of the reference rDNA sequences from the reference database; generating a plurality of rDNA vectors corresponding to a plurality of reference rDNA sequences; computing a frequency of hits of each of said plurality of reference clusters corresponding to said plurality of reference rDNA sequences, wherein the frequency of hits is computed based on at least one of a threshold distance and a threshold sequence count; comparing for each of the plurality of reference clusters, the computed frequency of hits with a predetermined frequency; pre-tagging the subset of reference clusters from said plurality of reference clusters as the probable rDNA clusters, when the computed frequency of hits exceeds the predetermined frequency; and identifying a plurality of ribosomal deoxyribonucleic acid (rDNA) sequences from a sample containing a plurality of unknown DNA sequences based on the information obtained from pre-tagging, wherein the identifying includes: creating a plurality of query sequences corresponding to said plurality of unknown DNA sequences by sequencing genetic material obtained from the sample; computing a distance between a query vector corresponding to each query sequence and a cluster centroid of each of the plurality of reference clusters, wherein each of the plurality of reference clusters include said plurality of reference sequences, and wherein said plurality of reference sequences with similar composition are classified into at least one reference cluster; selecting one or more target clusters corresponding to the query sequence from the plurality of reference clusters, wherein the one or more target clusters are selected based on, a comparison of the distance of each of the plurality of reference clusters with the threshold distance; and a comparison of a cumulative sequence count of said plurality of reference clusters with the threshold sequence count; computing the proportion of pre-tagged probable rDNA clusters within the one or more target clusters, and identifying the query sequence as a rDNA sequence, when the computed proportion of the pre-tagged probable rDNA clusters exceeds a predetermined proportion.