Incomplete dominance in the sense
1) In snapdragons, which are flowers, red flower color is dominant over white. However, there is incomplete dominance in the sense that the heterozygotes are pink. Pretend you are a horticulturalist, with your own nursery, and you sense that the demand for pink snapdragons is very high lately. What cross would you make to meet this demand?
2) Pink carnations result when a red carnation (R) mates with a white carnation (r). What will be the percent of offspring that will be pink if two pink flowers are mated to each other?
3) If a curly-haired person gets married to a straight-haired person, and they have children, what is the percent chance that their children will have straight hair? Wavy hair is incompletely dominant to both straight and curly hair.
4) Hypercholesterolemia is a disease in which the receptors for cholesterol in cells are either missing or non-functional. People who have the severe form of this disease often die in their 30s or 40s of heart disease. Someone who has a severe form of this disease is homozygous recessive (hh). Suppose a person normal for this trait (HH) marries someone who has the severe form of the trait. They have children. What would these parents say to their children about their nutrition as they age?
5) Palomino horses (brownish) are intermediates between chestnut (D, reddish) and cremello (d, whitish) horses. A palomino horse was mated to a cremello horse. What percentage of the foals will be cremello? Palomino?
To meet the demand for pink snapdragons, I would perform a cross between two heterozygous red snapdragons. This can be represented as:
RR (red) x RR (red)
The resulting offspring would include red, pink, and white snapdragons. Approximately 25% of the offspring would be red (RR), 50% would be pink (RW), and 25% would be white (WW). By consistently selecting and propagating the pink snapdragons from each generation, I can maintain a steady supply of pink snapdragons to meet the high demand.
When two pink carnations are mated with each other, the offspring will follow the principle of incomplete dominance. In this case, the genotypes of the parents are Rr (pink) x Rr (pink).
The possible genotypes of the offspring are RR (red), Rr (pink), and rr (white). The percentage of offspring that will be pink is 50%, as there are two possible genotypes (Rr and rR) out of a total of four possible genotypes (RR, Rr, rR, rr).
In this case, if a curly-haired person (CwCw) marries a straight-haired person (SS), the possible genotypes of their children will be CwS, CwS, SS.
Since wavy hair is incompletely dominant to both straight and curly hair, both CwS and CwS genotypes will display wavy hair. Therefore, there is a 100% chance that their children will have wavy hair.
If one parent has the severe form of hypercholesterolemia (hh) and the other parent is normal (HH), their children will all be heterozygous carriers for the disease (Hh).
As the children inherit one normal allele (H) and one recessive allele (h), they will not have the severe form of hypercholesterolemia themselves. However, it is important for the parents to educate their children about the potential risk of hypercholesterolemia and the importance of maintaining a healthy diet and lifestyle to manage cholesterol levels as they age.
When a palomino horse (Dd) is mated with a cremello horse (dd), the resulting offspring will have the following possibilities:
50% of the foals will be cremello (dd) because they inherit the recessive allele for whitish color from both parents.
50% of the foals will be palomino (Dd) because they inherit one dominant allele for brownish color from the palomino parent and one recessive allele for whitish color from the cremello parent.