Sponges are known to contain a single Hox gene. Most invertebrates have a cluster of 10 similar Hox genes, all located on the same chromosome. Most vertebrates have four such clusters of Hox genes, located on four non-homologous chromosomes. The process responsible for the change in number of Hox genes from sponges to invertebrates was most likely __________, whereas a different process that could have potentially contributed to the cluster's presence on more than one chromosome was __________. I. binary fission
II. translation
III. gene duplication
IV. non-disjunction
V. transcription

Question

Quizplus · Accepted Answer

The process responsible for the change in number of Hox genes from sponges to invertebrates was most likely gene duplication. This is because the cluster of 10 similar Hox genes in invertebrates suggests that an ancestral Hox gene underwent duplication, resulting in multiple similar genes on the same chromosome. A different process that could have potentially contributed to the cluster's presence on more than one chromosome was non-disjunction. Non-disjunction can result in chromosomes that have an abnormal number of genes, which could contribute to the clustering of Hox genes on multiple chromosomes in vertebrates.

Sponges Are Known to Contain a Single Hox Gene