Grey horse coat is governed by the dominant gene ‘G’ and non-grey coat by its re

Question

Grey horse coat is governed by the dominant gene ‘G’ and non-grey coat by its recessive allele ‘g’. Black horse coat is governed by an independently assorting gene ‘E’ and chestnut by its recessive gene ‘e’. When dihybrid horses (multiple pairs) were crossed over a number of years, 620 offspring had a grey coat, 138 with black coat and 52 with chestnut coat. .

a) What phenotypic ratio can be deduced from the above data?

b) What type of epistatic interaction (if any) is operative? Explain in words, and show a Punnett square to back up your explanation

Explanation / Answer

Grey = Dominant = GG or Gg

Non-grey = Recessive = gg

Black = Dominant = EE or Ee

Chestnut = Recessive = ee

Total progeny = 620 + 138 + 52 = 810

Offspring ratio:

Grey coat = 620 = 12

Black coat = 138 = 3

Chestnut coat = 52 = 1

Phenotypic ratio analysis:

12 = 9 + 3

9 = G_ E_ = Grey

3 = G_ ee = Grey

3 = gg E_ = Black

1 = gg ee = Chestnut

Inheritance pattern = DOMINANT EPISTATIC INHERITANCE

Related Questions

Navigate

• Browse (All)
• Browse G
• Subjects

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