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Name: Mike A Smola
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Question:
Why can frogs (some species) change sex?



Replies:
This is a complex subject. Several studies have exposed some of the answers to this question, but a definitive answer is yet to be made.

It all boils down to the level of which genes are activated. Studies have shown that the sex chromosomes are not necessarily the determining factor. The traditional display of a female is when an individual has two X chromosomes present. When one of these genes is a Y, it is a male. This tends to be the case for most organisms that sport individuals that are different sexes. However, the Y chromosomes has been almost always a male determining chromosome, but with molecular biology and genetic engineering techniques, a male can be made from a XX combination and females have developed from XY combinations. These are extremely rare, but they have given insight to the fact that there are other factors beside X and Y chromosomes that determine sex, probably a gene found in both chromosomes.

As far as frogs are concerned (and other organisms that display this Phenomenon), apparently there are chemical triggers that respond to the number of members in a population that will activate the gene(s) that will allow for the disintegration of one set of sex organs and the development of the other. This is an advantage to a species whereby they have evolved the ability to assure their reproductive success.

Steven D Sample



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