2. Identical twins are produced from the same sperm and egg (which splits after

Question

2. Identical twins are produced from the same sperm and egg (which splits after the first mitotic division), whereas fraternal twins are produced from separate sperm and separate egg cells. If two parents with brown eyes (a dominant trait) produce one twin boy with blue eyes, what are the following probabilities? A. If the other twin is identical, he will have blue eyes. B. If the other twin is fraternal, he or she will have blue eyes. C. If the other twin is fraternal, he or she will transmit the blue eye allele to his or her offspring. D. The parents are both heterozygotes

Explanation / Answer

A) The probability of other twin to have blue eyes is 100% because they are genetically identical.

B) The probability of other fratenal twin to have blue eyes is 25%. This can be known from constructing the punneltt square. The parents are heterozygous and produced blue color eyed offspring. Though the offspring is a fraternal twin not genetically identical but he or she have same parents.

C) There is possibility of the fraternal twin to inherit the blue colored eyes is of 50%. The fraternal twin has the possibility to pass the trait to their offspring would be 50%. By using the product rule (0.5) (0.5) = 0.25 or 25%. The fraternal twin has 25% probability to transmit the blue color eyes to their offsring.

D) If the mutatiom during gamete fromation is considered, then the parents must be 100% hetezygotes to produce the progeny with blue color eyes.

Related Questions

Navigate

• Browse (All)
• Browse 2
• Subjects

---

---

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