A gene cluster is a group of two or more genes found within an organism's DNA that encode similar polypeptides or proteins which collectively share a generalized function and are often located within
Hox genes have been observed among various phylum. Eight genes make up the Hox gene Drosophila. The number of Hox genes may vary among organisms, but the Hox genes collectively make up the Homeobox family.
Intrachromosomal duplication is the duplication of genes within the same chromosome over the course of evolution (a-1). Mutations may occur in the duplicated copy, such as observed with the substitution of guanine with adenine (a-2). Alignment of DNA sequences exhibits homology between the two chromosomes (a-3). All segments were duplicated from the same ancestral DNA sequence as observed by the comparisons in b(i-iii).