What is the actual meaning/philosophy lying under following method to define a new molecular target ?

Selection of a new molecular target

The target region of HSP70 was obtained for P jirovecii by designing generic primers to the flanking regions of P carinii. Nucleotide sequences for all Pneumocystis types available from public data repositories were searched using BlastX 24 against the non-redundant protein database. Expressed sequence tag data were assembled into contigs using CAP3 prior to searching in order to remove redundancy and improve sequence accuracy. Sequences with high quality matches (bit score 60) to proteins from a broad spectrum of eukaryotic species were considered further (minimally: Caenorhabditis elegans, Drosophila melanogaster, Saccharomyces
cerevisiae, Schizosaccharomyces pombe and Neurospora crassa)