Final answer:
The organizational phases of development are regulated by morphogens, transcription factors, and segmentation genes. These molecules control gene expression and determine cell fate and patterning during development.
Step-by-step explanation:
The organizational phases of development are regulated by morphogens, transcription factors, and segmentation genes. During development, these molecules play important roles in controlling the expression of genes that determine the formation of specialized cells and tissues.
Morphogens are signaling molecules that establish concentration gradients in developing tissues, providing positional information to cells. They help determine cell fate and patterning during development. Transcription factors are proteins that bind to DNA and control the expression of other genes. They regulate the activation or repression of specific genes at specific times, playing a crucial role in cell differentiation and development.
Segmentation genes control the formation of body segments during embryonic development. They determine where specific body structures will develop and play a role in the patterning and organization of the body plan.