Question

The gene that regulates normal morphogenesis during development is

• A. FMR-1 gene
• B. Homeobox gene
• C. P-16
• D. PTEN

Hint:

Homeobox (Hox) genes are the master transcription factor genes that set up the body's anteroposterior pattern during development.

Answer 1

The Correct Option is B

The question wants the gene family that lays down the body's basic layout while an embryo is forming. Let's check what each listed gene actually does.

1. FMR-1 gene: This gene, when its repeat sequence expands abnormally, causes fragile X syndrome, a cause of intellectual disability. It has nothing to do with laying down body structure.
2. Homeobox gene: These genes produce transcription factors that turn on the correct set of other genes in each body segment, telling cells where they are along the head to tail axis and how to form structures like limbs. This is the literal definition of controlling morphogenesis.
3. P-16: This is a tumor suppressor that blocks the cell cycle machinery, guarding against uncontrolled cell division, not a patterning gene.
4. PTEN: Another tumor suppressor, this one dampens a growth signaling pathway, and its loss is tied to several cancers, again unrelated to body patterning.

Since only one option actually directs the embryo's structural blueprint, the homeobox gene is the answer.

Let's summarize:

• Homeobox (Hox) genes control body segment identity and organ patterning.
• FMR-1, P-16 and PTEN are involved in neurodevelopment or tumor suppression, not general morphogenesis.

The correct answer is the homeobox gene.