The diagram illustrates the function of the master control gene.
The master control gene sends signals to other genes in a sequence of DNA. Based on this diagram, a change in the sequence of the master control gene could affect how
a
gene 4 regulates the master control gene.
b
gene 1 regulates the expression of gene 3.
c
genes 1 and 2 regulate the expression of gene 3.
d
genes 1 and 3 regulate the expression of gene 2.