Question

coat color is due to a dominant allele (W), black coat color to its recessive allele unnett squares for each of the following crosses and answer the questions. 2. In sheep, white tw). Construct P d frequency fo a. A black sheep crossed to a black sheep. List the genotypes, phenotypes, an each of the offspring b. A white sheep, the product of a black x white cross, is crossed with a black sheep. List the genotypes, phenotypes, and frequency for each of the offspring. c. A white sheep crossed to a white sheep produces offspring that are both white and black. i. What are the genotypes of the parents? ii. List the genotypes, phenotypes, and frequency for each of the offspring. Which features would characterize pedigrees of dominant traits? Of recessive traits? 3. Can you determine the genotype of any individual in the pedigree? Explain your answer 4. 1 Genetics 1175

Answer 1

Answer:

2).

a).

Black (ww) x black (ww) –Parents

All progeny are black (ww)

b).

White (Ww) x black (ww)---Parents

	w
W	Ww (white)-50%
w	ww (black)-50%

c).

i).

Both the parental genotype is Ww

ii)

Ww x Ww ---Parents

	W	w
W	WW (white)	Ww (white)
w	Ww (white)	ww (black)

White = ¾ or 75%

Black = ¼ or 15%

WW = ¼ or 25%

Ww = ½ or 50%

ww = ¼ or 25%

3).

The presence of trait in F1 progeny when a cross was made between two differen true breeding traits was called dominant trait.

The dominant trait is expressed in both homozygous and heterozygous genotype.

The recessive trait is expressed in homozygous genotype condition only.

4).

Genotype of (dominant) individual can be determined by testcross. Testcross was done between unknown dominant phenotype with known recessive phenotype. If all testcross progeny are dominant, then the unknown genotype is homozygous dominant.

White (WW) x black (ww)---Parents

	w
W	Ww (white)-100%

If 50% testcross progeny are dominant phenotypes and 50% recessive phenotype, then the unknown genotype is heterozygous dominant.

White (Ww) x black (ww)---Parents

	w
W	Ww (white)-50%
w	ww (black)-50%