on an African safari you find two true breeding strains of a unlque giraffe One

Question

on an African safari you find two true breeding strains of a unlque giraffe One strain has spots and long horns and the other has turquoise spots and short horns. When the two are crossed, all the Fs individuals have turquoise spots and short horns. You then cross strains the F1 heterozygote with a testcross individual a. Use S/s for the spots trait and H/h for the horn trait to define your alleles. Use from class (capital- dominant allele, lowercase recessive allele) b. Write the genotypes (as the alleles appear on chromosomes) and corresponding phenotynes of each of the following giraffes: both true breeding parent giraffes, the F progeny and the testcross giraffe. If the two genes are NOT linked and you cross of the F1 parent with a testcross individual, state the phenotype of each of the resulting progeny and the percentage of total progeny each phenotype would represent c. d. You are told that the two genes ARE linked and are 8 map units apart, From the cross of the F1 parent with a testcross individual, state the phenotype of each of the resulting progeny and the percentage of total progeny each phenotype would represent.

Explanation / Answer

1. As all the heterozygous F1 progeny have torquoise spot and short horn, so torquoise spot and short horn must be the dominant phenotype.

H allele represent short horn

h allele represents long horn

S represents torquoise spot

s represent purple spot

2. The genotype of the true breeding parents are HHSS and hhss

F1 genotype

HhSs

torquoise spot and short horn

HhSs

torquoise spot and short horn

HhSs

torquoise spot and short horn

HhSs

torquoise spot and short horn

Genotype of the Test cross individual - hhss

c) If the two genes are not linked the test cross phenotypes:

HhSs

Short horn torquoise spot

HhSs

Short horn torquoise spot

Hhss

Short horn purple spots

Hhss

Short horn purple spots

hhSs

long horn torquoise spots

hhSs

long horn torquoise spots

hhss

long horn purple spots

hhss

long horn purple spots

Percentage of Short horn torquoise spot -25%

Percentage of Short horn purple spots-25%

Percentage of long horn torquoise spots-25%

Percentage of long horn purple spots-25%

4. If the two genes are linked so that means HS and hs will always remain together so the following test cross will take place

HhSs

Short horn torquoise spot

HhSs

Short horn torquoise spot

hhss

long horn purple spots

hhss

long horn purple spots

Short horn torquoise spot-50%

long horn purple spots-50%

hs hs HS

HhSs

torquoise spot and short horn

HhSs

torquoise spot and short horn

HS

HhSs

torquoise spot and short horn

HhSs

torquoise spot and short horn

Related Questions

Navigate

• Browse (All)
• Browse O
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.