I need help with these: 1. Charles was married once before, & he and his first wife had a child who suffers from cystic fibrosis. His current wife Elaine's brother died of cystic fibrosis. What is the probability that Charles & Elaine will have a baby with cystic fibrosis? Let's say A= normal, a= has cystic fibrosis. If Elaine's brother's genotype is aa, that means both parents carry the recessive allele. From here, I am stuck. How do I know whether the parents are both heterozygous or if one parent is homozygous recessive & the other parent heterozygous. How do I know if Elaine is AA or Aa? 2. T= tall, t= short; Y= yellow, y= green A green tall pea plant is crossed with a yellow short plant. Their offspring are as follows: 77 green short 81 yellow short 79 yellow tall 84 green tall What are the genotypes of the parent plants? Since there are 4 different phenotypes, I'm assuming that the offspring came from the selfing of a plant with genotype YyTt. I found the phenotypic ratios from this data and they all seem fairly close to each other, almost the same (24%, 25%, 25%, 26%) but don't know where to go from here.