daveyboy1969

while trying to fall asleep and thinking about epigenetics it occurs to me that current theories seem to suggest that epigenetic changes--sort of the master gene controller which turns various genes on and off, discontinues using "out dated" genes all together etc--would be perfectly suited to handle gradually occuring long-term and even extreme infrequent short-term changes in the environment without the need for any major base pair mutations, hence little or no changes to the genetic code over even a very long time i.e., the T-Rex basically unchanged for almost 20 millions years (granted fossil remains leave us only to speculate on changes to brain function, endocrin function, etc but i think everyone will agree that fossil and skeletal remains can speak volumes about an individual specimen as well as an entire species when enough specimens are uncovered). however, I'm thinking that extreme changes to the enviroment, particulary frequest recurring changes, back and forth, back and forth etc, much like hominids experienced in Africa for nearly 70,000 years--hot/dry to cool wet and back again, leading of course to extreme changes in diet, prey and predation habits, stresses on social cohesion, mating habits etc sometimes occuring in as little as a few centuries based on the geologic record--would cause what I am calling "epigenetic overload", meaning the epigenetic "system" would be deluged with extreme demands on its abilities to turn off and on enviromental adaptive type genes to deal with the constant changes, biological adaptive CHAOS! So, what is a poor over worked epigentic control system to do? Upon reaching some "critical mass" of demands, via a yet unknown process, it transfers the job of enviromental adaptation to the gene sequence itself, BAM! a base pair change or possible several base pair changes depending on the level of enviromental chaos, a new base pair order is created, mutated genes, and a whole new set of amino acid and proteins are employed to "takes over" if you will, from the over worked epigenetic controller so it can get back to more mundane day to day epigenetic tasks for which it is well suited. Hence, two populations of the same species seperated by a great distance, one exposed to scores of milenia of enviromental chaos, the other, not so much, will envariably appear very different in say 100,000 years i.e, home erectus v neanderthal v homo sapien etc.. They may still be able to interbreed--face it, 100,000 years of chaos is still a blink of an eye in evolutionary terms--but seperate them for a handful of millions of years and BAM! enough cumulative base gene mutations and you have two different species with no ability to interbreed, i.e, humans and apes only seperated by approx 5 million years. anyway, thats what kept me from falling asleep, I'm sure the theory has more holes than a block of emmental but at least now i may be able to catch some zzzzzs comments welcome

I hold to the epigenetic theory of homosexuality; namely, that a male fetus which is epigenetically programmed to be hyper sensitive to testosterone and hypo sensitive to estrogen--for obvious reasons--while in the womb will sometimes later in life pass that epigenetic programming to his unborn daughter who will be similarly hyper sensitive to testostorone and hypo sensitive to estrogen while in the womb leading to the masculization of the female fetus. Likewise, a female fetus which is epigenetically programmed to be hyper sensitive to estrogen to and hypo sensitive to testosterone--as normally occurs--will sometimes pass that epigenetic programming to her unborn son who will be likewise hyper sensitive to estrogen and hypo sensitive to testosterone while in the womb leading to feminization of the male fetus. It also seems reasonable that the degree to which the mis-programmed sensitivity/insensitivity to sex hormones is passed to the child of the opposite sex will vary greatly from person to person leading to a wide spectrum of psychological sexual characteristics aka the Kinsey Scale. comments please. lol now I see that this topic was covered in earlier posts... but I would like to add that occasional fauty epigenetic inheritences of this type would seem to preclude the need for any adaptive/natural selection explanations...