Misexpression of which of the following homeobox genes alters the position of the forelimbs during development –
**Core Concept**
Homeobox genes are a family of transcription factors that play a crucial role in the development and patterning of various tissues and organs, including the limbs. They are involved in the regulation of gene expression and cell fate determination during embryogenesis. The misexpression of these genes can lead to alterations in the normal developmental process, resulting in abnormalities in the formation and positioning of tissues and organs.
**Why the Correct Answer is Right**
The misexpression of the Homeobox gene **Hoxc-8** has been shown to alter the position of the forelimbs during development. This is because Hoxc-8 is a member of the Hox gene family, which is responsible for specifying the identity and position of limb buds along the anteroposterior axis. Misexpression of Hoxc-8 in the forelimb bud can lead to the formation of extra digits or the fusion of digits, resulting in abnormalities in forelimb development.
* **Option A:** Misexpression of Hoxa-13 is associated with abnormalities in the development of the hindlimbs, not the forelimbs. Hoxa-13 is involved in the specification of the hindlimb bud and the formation of the digits.
* **Option B:** Misexpression of Pax6 is associated with abnormalities in eye development, not limb development. Pax6 is a transcription factor involved in the development of the eye, brain, and pancreas.
* **Option C:** Misexpression of Wnt1 is associated with abnormalities in neural crest development, not limb development. Wnt1 is a signaling molecule involved in the development of the neural crest and the formation of various tissues and organs.
**Clinical Pearl / High-Yield Fact**
The Hox gene family is a group of transcription factors that play a crucial role in the development and patterning of tissues and organs. Misexpression of these genes can lead to abnormalities in the formation and positioning of tissues and organs, resulting in various congenital anomalies.
**Correct Answer:** C. Misexpression of Wnt1 is associated with abnormalities in neural crest development, not limb development. Wnt1 is a signaling molecule involved in the development of the neural crest and the formation of various tissues and organs.