**Core Concept:**
Pharmacogenomics is a field of medicine that studies how genetic variations affect an individual's response to drugs. During development, the gene responsible for regulating morphogenesis is crucial for proper tissue formation and organogenesis. In this context, morphogenesis refers to the process of organ formation and tissue development.

**Why the Correct Answer is Right:**
The correct answer, **D**: **GDF5 (Growth and Differentiation Factor 5)** is a master regulator gene that plays a crucial role in the development of various tissues and organs in vertebrates. GDF5 is a member of the TGF-beta (Transforming Growth Factor beta) superfamily of proteins, which are involved in cell differentiation, proliferation, and apoptosis (programmed cell death). GDF5 regulates bone, joint, and cartilage development, as well as limb development and patterning.

**Why Each Wrong Option is Incorrect:**
A. **FGF8 (Fibroblast Growth Factor 8)** is a gene involved in early embryonic development, particularly in the developing limb buds, where it regulates limb patterning, outgrowth, and differentiation. Although it is important, it is not the gene responsible for regulating normal morphogenesis during development as a whole.

B. **BMP4 (Bone Morphogenetic Protein 4)** is involved in bone, cartilage, and tooth development. While it plays a role in limb development, it is not the master regulator gene for normal morphogenesis during development.

C. **FOXP1 (Forkhead Box P1)** is a transcription factor gene involved in the development of the brain, heart, and limbs. While it is essential for proper development, it is not the gene responsible for regulating normal morphogenesis during development as a whole.

**Clinical Pearl:**
Understanding the role of genes like GDF5 and their involvement in development is essential for understanding the pathophysiology of developmental anomalies and genetic disorders. This knowledge is crucial for diagnosing and treating such diseases, and for counseling families with known genetic disorders.

**Correct Answer Explanation:**
GDF5 (Growth and Differentiation Factor 5) is a master regulator gene that controls various aspects of embryonic development, including bone, cartilage, and joint formation, as well as limb development and patterning. Its role in regulating normal morphogenesis during development makes it the correct answer.