Question

Which of the following is FALSE regarding hox Genes?

Group of answer choices

They serve the role of defining segmental regions along the anterior to posterior axis during development

Their functions have diversified through gene duplications followed by differentiation (e.g. subfunctionalization), leading to differentiation of segmental regions in animals

They encode transcription factors that perform trans-regulatory functions

They are responsible for the major body plan differences among animal phyla

Answer 1

Ans 3 is false.

1. The Hox genes act as markers of position , defining segmental regions along the antero-posterior axis of the body during development.

2. Hox genes have resulted from events early in evolution that include segmental duplications and gene duplication. They are responsible for driving the differentiation of segmental regions in animals.

3. The Hox genes encode transcription factors that are involved in neural development, organogenesis and segmental development of branchial and mesoderm layers. Also determine cell and tissue identities in the embryo during development.

The trans-regulatory elements are genes which may modify (or regulate) the expression of distant genes. So this is false.

4. The hox genes are responsible for determining the general body plan, such as the number of body segments of an animal, the number and placement of appendages, and animal head-tail directionality and marks the position along the antero-posterior axis of the body in nematodes, arthropods, chordates, and by implication, most other triploblastic phyla.