In chickens, congenital baldness results from a Z-linked recessive gene. A bald rooster is mated with a normal hen. The Fi from this corss are interbred to produce the F2.. The F2 progeny will include?

A. only normal roosters & hens

B. only bald roosters & hens

C. only normal roosters & bald hens

D. only bald roosters & normal hens

E. normal roosters & hens and bald roosters & hens

Explanation:

The sex chromosomes of the chickens are represented by ZZ for male chicken that is rooster and ZW for the female chicken that is hen.

In the given question, the genotype of the bald rooster is zz and the genotype of the normal hen is ZW.

So the F1 progeny are, Zz that is normal male and the zW that is bald female.

So F1 × F1

                        Zz × zW

Thus, F2 progeny are Zz ( normal rooster), zz ( bald rooster), ZW ( normal hen), zW ( bald hen).

advantage of using stem cells in medical research:

1.       it provides medical benefits in the fields of therapeutic cloning and regenerative medicine.

2. it provides great potential for discovering treatments and cures to a variety of diseases including parkinson disease, spinal cord injuries, diabetes, alzheimer’s disease and many more.

3. limbs and organ could be grown in lab from stem cells and then used in transplant or treat illness.