Gregor Mendel was a monk who, in 1865, suggested a theory of inheritance based on the science of genetics. He identified heterozygous individuals for flower color that had two alleles (one r = recessive white color allele and one R = dominant red color allele). When these individuals were mated, 3/4 of the offspring were observed to have red flowers, and 1/4 had white flowers. The following table summarizes this mating; each parent gives one of its alleles to form the gene of the offspring.
|
Parent 2 |
| Parent 1 |
r |
R |
| r |
rr |
rR |
| R |
Rr |
RR |
We assume that each parent is equally likely to give either of the two alleles and that, if either one or two of the alleles in a pair is dominant (R), the offspring will have red flowers. What is the probability that an offspring has
a. at least one dominant allele?
b. at least one recessive allele?
c. one recessive allele, given that the offspring has red flowers?