Questions 2-3: The Igf2 gene encodes insulin-like growth factor 2, a protein tha

Question

Questions 2-3: The Igf2 gene encodes insulin-like growth factor 2, a protein that is important for normal growth. In mice, no expression of the Igf2 gene results in a growth deficiency and a small mouse phenotype. The Igf2 gene is maternally imprinted and autosomal.

3. (2pts) A female mouse is heterozygous for a null allele of the Igf2 gene and mates with a male that is heterozygous for a null allele of the Igf2 gene. What is the expected phenotypes of their progeny?

All small progeny

All wildtype progeny

25% small progeny and 75% wildtype progeny

50% small progeny and 50% wildtype progeny

75% small progeny and 25% wildtype progeny

all small males and all wildtype females

all wildtype males and all small females

All small progeny

Explanation / Answer

Answer: 50% small progeny and 50% wildtype progeny

Explanation:

Maternal imprinting means that the allele of a particular gene inherited from the mother is transcriptionally silent and the paternally- inherited allele is active. For example, the gene encoding insulin-like growth factor 2 (IGF2/Igf2) is only expressed from the allele inherited from the father

IGF2 (M) / Igf2(M) x IGF2 (F) / Igf2(F)----Parents

IGF2 (F) Igf2(F) IGF2 (M) IGF2 (F) / IGF2 (M) (wild) Igf2(F) / IGF2 (M) (small) Igf2(M) IGF2 (F) / Igf2(M) (wild) Igf2(F) / Igf2(M) (samll)

Related Questions

Navigate

• Browse (All)
• Browse Q
• Subjects

---

---

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