Evolution: time for some change?

Originally posted by spookz
very nice sci. excellent attitude. a pox on the other retards

A fascinating example of epigenetic inheritance is available if one looks to the reptile world. While the sex of human offspring is determined genetically, in turtles two mechanisms exist: both a genetic mechanism and an epigenetic mechanism. Turtles are sex-typed at the time of fertilization but can have their sex reversed if the temperature during a specific phase of their development is appropriate to induce the change. Specifically, high temperatures are feminizing and lower temperatures are masculinizing. The temperature of a nest is often dictated by the mother's choice of nesting sites

While the existence of phenotypic plasticity based on epigenetic inheritance does not necessarily point up the inheritance of the manifested phenotype there is a possibility that all people are vested with a wide range of phenotypic possibilities. If this turns out to be the case then one's mother (and quite possibly father) are capable of effecting a child's phenotype based on their biochemical states at the time of conception and based on the mother's biochemical state throughout the pregnancy. (Sura, 1995)

*now with a little help from my yogi, i plan to bring a horned little devil into the world. ta y'all
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if I may invoke a caveat; please keep in mind your sources. a 'click' on the Sura 1995 link actually brought us to Kristl Smith's (a business analyst, with no biology background that I can determine from her resume) opinions on this topic, from whom you quote. I am not disregarding her opinions at all. She appears to be well read on the subject, but she is no authority on the subject by any means, and the implication of your reference is an appeal to authority. 'nuff said.
 
paulsamuel,
Sorry about the link. I actually emailed that link to someone else recently and must have accidently not copied the Rutherford and Lindquist link and then didn't notice I had screwed up when it was an ncbi link ...

I think the immune system is cool, but I've never managed to slug through remembering all the different things and what they do exactly. If I remember correctly MHC genes are involved in antigen presentation. How do receptors that display fragments of broken down proteins play an important evolutionary role? I'd be curious to hear a bit about it.

Spookz,
My main issue with the turtles thing is that it's not even epigenetic inheritance, it's developmental plasticity. It would be epigenetic if the mother programmed her eggs to be female if she was hot and males if she was cold regardless of their chromosome complement (otherwise it would just be genetic). Developmental plasticity though is equally if not more interesting to me than epigenetic inheritance. Still I'd try doing pubmed searches and getting free articles rather than web searches and getting things of questionable authority.
 
Originally posted by paulsamuel
if I may invoke a caveat; please keep in mind your sources. a 'click' on the Sura 1995 link actually brought us to Kristl Smith's (a business analyst, with no biology background that I can determine from her resume) opinions on this topic, from whom you quote. I am not disregarding her opinions at all. She appears to be well read on the subject, but she is no authority on the subject by any means, and the implication of your reference is an appeal to authority. 'nuff said.
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i will remedy my carelessness. thanks
 
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