Prudentia wrote:20 characters! wrote:Prudentia wrote:
An interesting idea, the only issue is that it would more or less be randomly expressed. Take for example, the parietal eye of the Tuatara. A highly developed structure, it even comes with a retina and lens. However, the optic nerve is highly degenerate, and would not be capable of a full image transmission, only light sensitivity. usually epigenetics do not hide whole structures, though it is the sole mechanism responsible of organ differentiation. So it is theoretically possible,in Complete Androgen Insensitivity Syndrome (CAIS), an XY male possesses testes but is unresponsive to androgen. Causing the creation of a vagina, and in extreme cases, uterus and Mullerian tissue that remain intact even after the anti-Mullerian hormone. These genetic males are usually raised as females.
While not caused by epigenetics, something causes (a mutation the AR gene, 95% of the time) the body to treat androgen as estrogen and changes the epigenetic patterns in the developing embryo. Causing the creation of various feminine equipment, most of which is later dismantled by anti-mullerian hormone, though vaginas and breasts tend to remain.
Different genes are more prone to mutation, but # limbs and other vertebrate/ tetrapod defining traits are less prone. Especially when it comes to adding limbs. Genes that affect development are some of the most resistant. Though mutations do happen, most in those departments are fatal, around 30-40% of human pregnancies miscarry before they are even detectable. Most issues in development are not mutations but failure of apoptosis or results of chemicals that slow or stop some to all areas of development.
Most of our epigenetic patterns are still determined in the womb. For example, if woman (pregnant with a girl) continues to heavily smoke during pregnancy, she may elicit epigenetic changes that can make her, her unborn child, and her unborn child's eggs more vulnerable to certain types of cancer.
Those "mostly stable genes" you speak of are mostly hox genes are they not?
Those would be Hox, yes. Most mutations in those are highly lethal.
I found a nice interesting nonleathal hox gene study which along with a few things will be adding to the TIL thread but I'll link to you first
http://www.nature.com/nature/journal/v5 ... 19813.html