determination of sex

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protozoan
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determination of sex

Post by protozoan » Thu Aug 04, 2005 5:26 pm

I heard that in reptiles determination of sex can be determined by the temperature in which embryos are developing. In mammals it is clear given by the chromosome which sperm who enter ovum carries (X or Y). Does this mean that in reptiles chromosome set doesnt contain specific sex-linked chromosomes?
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Abstract
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Post by Abstract » Thu Aug 04, 2005 7:40 pm

Correct. Reptiles don't have specific gender genes.

The gender of the embryo is, as you pointed out, mainly due to temperature. Most species' embryos start out as female, and then a chemical change must occur for the embryo to become male. In reptiles, these changes are due to enzymatic action.

Enzymes operate optimally within a very specific range of conditions (pH, temperature, etc.). As such, when the temperature is below a certain point, the enzymes cannot act on the embryo efficiently, and the embryo remains female. If the temperature gets above a certain point, the enzymes go to work, and a male develops.

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Post by Beetle » Sat Aug 06, 2005 1:38 pm

Just to add that nothing is simple in nature. Some reptilians have two diapason of temperature when female will develop (low and high temp.) and one for male (meduim temp.).
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Post by victor » Sun Aug 07, 2005 12:57 pm

Yup, I agree..nothing is as simple as chemical reaction in my chemistry book (for high school) in organisms' biochemistry.
For a little information, at low and high temp, the sex steroid substance remains at Methyl ketone form in the functional side (it's female) while at medium temp, this form will change to Hydroxil form (it's male).
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protozoan
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Post by protozoan » Sun Aug 07, 2005 1:22 pm

Thanks, great info. I see that my signature pretty works. So theres potential for female reptile to change to male in adult cause in their genetic fond are either plans. I heard that some amphibians can do that.
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Post by victor » Sun Aug 07, 2005 1:33 pm

Hm, according to 'Jurassic Park' movie, they can...Actually the changing is pretty simple...only changes from:
O
ll
R-C-CH3 (female) to R-CH2-OH (male)
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