Question

analysis questions:

1. please make sure your drawing has the genotype and phenotype clearly listed for each characteristic.
2. assume that both parents (you and your partner) are heterozygotes for all traits. what did the single side of a double sided coin represent?
3. how do allele combinations occur in nature and why is a coin toss a good way to represent this?
4. shape of eyebrows is a trait that exhibits complete dominance (b = bushy, b = fine). calculate the ratios & percentages of the offspring for a cross between two heterozygous parents.

(a punnett square chart is shown here)
genotypic ratio:
phenotypic ratios:
genotypic %
phenotypic %

1. for the traits explored in this lab, do all heterozygous pairs of alleles produce an intermediate phenotype? why or why not?

Explanation:

Step1: Determine the genotypes of the parents

Since both parents are heterozygous for the eyebrow - shape trait, their genotypes are \(Bb\) and \(Bb\).

Step2: Create a Punnett square

	B	b
b	Bb	bb

Step3: Calculate the genotypic ratio

From the Punnett square, the genotypes are \(BB:Bb:bb = 1:2:1\).

Step4: Calculate the phenotypic ratio

Since \(B\) (bushy) is dominant over \(b\) (fine), \(BB\) and \(Bb\) have the bushy phenotype, and \(bb\) has the fine phenotype. So the phenotypic ratio is \(Bushy:Fine=3:1\).

Step5: Calculate the genotypic percentages

The total number of genotypes is \(4\). For \(BB\): \(\frac{1}{4}\times100\% = 25\%\), for \(Bb\): \(\frac{2}{4}\times100\%=50\%\), for \(bb\): \(\frac{1}{4}\times 100\% = 25\%\).

Step6: Calculate the phenotypic percentages

For the bushy phenotype (\(BB + Bb\)): \(\frac{3}{4}\times100\% = 75\%\), for the fine phenotype (\(bb\)): \(\frac{1}{4}\times100\%=25\%\).

Answer:

Genotypic Ratio: \(1:2:1\)
Phenotypic Ratios: \(3:1\)
Genotypic %: \(25\%,50\%,25\%\)
Phenotypic %: \(75\%,25\%\)