Final answer:
The slx gene in fruit flies and Hox genes are examples of transcription factors that regulate morphology and differentiation by controlling gene expression. These are crucial for determining sexual characteristics and embryonic development.
Step-by-step explanation:
An example of a transcription factor gene that regulates morphology and cell differentiation is the slx gene in Drosophila, which determines sex by influencing the splicing of the tra gene. This determines sex-specific gene expression that results in different sexual characteristics. Additionally, Hox genes provide evidence of shared ancestry due to their conserved role in cell and tissue specialization during embryonic development by regulating transcription factors that control the on and off states of specific genes. These homeobox genes function as transcription factors containing homeodomains that bind and regulate other genes, playing a crucial role in the organism's developmental process.