Suppose that a dominant allele (p) codes for a polka-dot tail and a recessive allele (p) codes for a solid colored tail. if two heterozygous individuals with polka-dot tails mate, what's the probability of the phenotype and genotype combinations of the offspring?
a. 75 percent chance of a polka-dot tail and 25 percent chance of a solid colored tail (75 percent pp; 25 percent pp)
b. 75 percent chance of a polka-dot tail and 25 percent chance of a solid colored tail (25 percent pp; 50 percent pp; 25 percent pp)
c. 25 percent chance of a polka-dot tail and 75 percent chance of a solid colored tail (25 percent pp; 50 percent pp; 25 percent pp)
d. 50 percent chance of a polka-dot tail and 50 percent chance of a solid colored tail (50 percent pp; 50 percent pp)

step 1: initiation

initiation is the beginning of transcription. it occurs when the enzyme rna polymerase binds to a region of a gene called the promoter. this signals the dna to unwind so the enzyme can ‘‘read’’ the bases in one of the dna strands. the enzyme is now ready to make a strand of mrna with a complementary sequence of bases.

step 2: elongation

elongation is the addition of nucleotides to the mrna strand. rna polymerase reads the unwound dna strand and builds the mrna molecule, using complementary base pairs. there is a brief time during this process when the newly formed rna is bound to the unwound dna. during this process, an adenine (a) in the dna binds to an uracil (u) in the rna.

step 3: termination

termination is the ending of transcription, and occurs when rna polymerase crosses a stop (termination) sequence in the gene. the mrna strand is complete, and it detaches from dna.

substitution is the answer in this case