Comparative Genomic Analysis and Evolutionary Study of CD4 Antigen

CD4 antig en is important to act as th e prim ary receptor for the HIV. In order to understand th e human CD4 gene and to determine its evolutionary aspects, we characterized this gene in detail in six different organisms. A comparative study was made of nucleotide length variations, intron and exon sizes and number variations, differential compositions of coding to non-coding bases, etc., to look for similarities/dissimilarities in the CD4 gene across all six taxa. Phylogenetic analysis showed the pattern found in other genes, as Homo sapiens and Pan troglodytes were placed in a single clade, and Rattus norvegicus and Mus musculus in another. We further focused on the two primates and aligned the amino acid sequences; there were small differences between humans and chimpanzees; both were more different from the other organisms.