Question

Which of the following phrases INCORRECTLY completes the following statement? The Hox complexes of mammals

A. encode genes homologous to those found in the antennapedia and bithorax complexes.
B. follow the colinearity rule.
C. are located on a single chromosome, similar to what is seen in Drosophila.
D. determine cell fate on the anteroposterior axis.
E. suggest there is a basic body plan that is followed by all multicellular organisms.

Answer 1

The incorrect statement about mammal Hox complexes is that they are located on a single chromosome, similar to what is seen in Drosophila. In fact, mammals have their Hox genes spread across multiple chromosomes organized into four clusters.

Step-by-step explanation:

The phrase that incorrectly completes the statement "The Hox complexes of mammals" is C. are located on a single chromosome, similar to what is seen in Drosophila. While Drosophila, or fruit flies, have a single Hox cluster on one chromosome that determines the body plan, vertebrates including mammals, have multiple Hox clusters spread across different chromosomes. These Hox genes are responsible for the development of the anterior-posterior body axis in vertebrates and are highly conserved across the animal kingdom, reflecting a common ancestry. However, with respect to their chromosomal location, mammals have Hox genes organized into four clusters known as Hox-A, Hox-B, Hox-C, and Hox-D, and not on a single chromosome. This complex arrangement allows mammals a greater complexity in body plan and tissue differentiation.