Scientists subsitute a nucleus from a frog sperm cell and no adult frog developed. Why?

Question

Scientists subsitute a nucleus from a frog sperm cell and no adult frog developed. Why would a sperm cell nucleus not work in this procedure?

Answer 1

The sperm cell is haploid, it only has half of the usual chromosome content. You need a diploid nucleus to clone a frog.

Answer 2

You need to give a bit more information - i.e. is the nucleus coming from the sperm cell, or is the sperm cell nucleus being replaced by a diploid nucleus? Your question suggests that the sperm nucleus is being replaced. If this is the case (and the replacement nucleus is diploid), this cell will not develop because several factors and receptors (present in the egg) will be missing. If the sperm nucleus is being transferred to an egg then Floundering's answer is correct. (It is however quite easy to induce haploid plant cells to undergo embryogenesis; this may eventually be feasible in animals).

Incidentally, cloned frogs do not develop beyond the tadpole stage regardless (they die during metamorphosis). Frog cloning was first succesfuly attempted in the 1970's, but to my knowledge this barrier has not been overcome. Frogs need to express several key master developmental genes (such as Hox genes) more than once during development (first as they develop into tadpoles and again as they metamorphose into frogs). It would appear that the genes become irreversibly methylated and cannot be accessed a second time.