Question

applied genetics practice problems
use the notes from class to help, answer on separate sheet, show your
punnett squares! .

1. blue - haired blips are crossed with yellow - haired blips. all of the offspring have green

hair. hair color in blips is an example of what type of dominance?

1. a snert with purple spots mates with a snert with pink spots. how would you tell that

spot color is codominant?

1. a green - striped dowop and a yellow - striped dowop have 12 offspring.

3 have green stripes, 3 have yellow stripes, and 3 have green and yellow stripes. the
other 3 have no stripes at all. how could you explain having four different
phenotypes?

1. sickle cell anemia is a codominant gene. if two parents who are heterozygous for the

sickle cell trait have children, what percentage would be homozygous for the
disease?

1. a trait for snapdragon flower is controlled by incomplete dominance. a red flower is

crossed with a white. what percent will have pink flowers?

1. if two pink flowers are crossed, what percent of the offspring would have pink

flowers?

1. a pink snapdragon is crossed with a red. what percent of the offspring can be

predicted to have white flowers?

1. roan color in cattle is controlled by codominant genes for both red (r) and white (w)

hair. if a roan cow is crossed with a white bull, what percent of the offspring would
be white?

1. a woman with type ab blood marries a man with type o blood. what are the

possible blood types of their children?

1. a woman with heterozygous type a blood (i^a i) marries a man with type ab blood

(i^a i^b). their children could have all of the following blood types except which of the
following?

Explanation:

Let's solve problem 4:

Step 1: Define the alleles

Let \( S \) represent the normal allele and \( s \) represent the sickle cell allele. Since it's codominant, heterozygous individuals have the genotype \( Ss \), showing both traits (some normal and some sickle - shaped red blood cells).

Step 2: Set up the Punnett square

The parents are both heterozygous (\( Ss \)). The Punnett square for a cross between two \( Ss \) individuals is:

	\( S \)	\( s \)
\( s \)	\( Ss \)	\( ss \)

Step 3: Determine the homozygous for the disease genotype

The genotype for homozygous with the sickle cell disease is \( ss \). From the Punnett square, out of 4 possible genotypes (\( SS \), \( Ss \), \( Ss \), \( ss \)), only 1 is \( ss \).

Step 4: Calculate the percentage

To find the percentage, we use the formula: \( \text{Percentage}=\frac{\text{Number of } ss \text{ genotypes}}{\text{Total number of genotypes}}\times100\% \)
Substituting the values, we get \( \frac{1}{4}\times 100\% = 25\% \)

Answer:

25%