Recent Studies On The Genetic Factors That Influence Gender Traits
For a long time, biologists believed that the female form was the default template for the mammalian fetuses of both sexes. After the discovery of the testis-determining gene SRY, many scientists shifted to the theory that the genetic mechanism that determines a fetus to develop into a male form was initiated by the SRY gene, which was thought to be responsible for the production of testosterone and its overall effects on body and brain development. This perspective still shared the classical way of thinking; that in order to produce two sexes, nature has developed a default female pathway and an active pathway by which male genes would initiate the process of determining a male sex, as something that is developed in addition to and based on the default female form. This view is no longer considered accurate by most scientists who study the genetics of sex. In an interview for the Rediscovering Biology website, researcher Eric Vilain described how the paradigm changed since the discovery of the SRY gene:
| “ | For a long time we thought that SRY would activate a cascade of male genes. It turns out that the sex determination pathway is probably more complicated and SRY may in fact inhibit some anti-male genes.
The idea is instead of having a simplistic mechanism by which you have pro-male genes going all the way to make a male, in fact there is a solid balance between pro-male genes and anti-male genes and if there is a little too much of anti-male genes, there may be a female born and if there is a little too much of pro-male genes then there will be a male born. We entering this new era in molecular biology of sex determination where it's a more subtle dosage of genes, some pro-males, some pro-females, some anti-males, some anti-females that all interplay with each other rather than a simple linear pathway of genes going one after the other, which makes it very fascinating but very complicated to study. |
” |
In mammals, including humans, the SRY gene is responsible with triggering the development of non-differentiated gonads into testes, rather than ovaries. However, there are cases in which testes can develop in the absence of an SRY gene (see sex reversal). In these cases, the SOX9 gene, involved in the development of testes, can induce their development without the aid of SRY. In the absence of SRY and SOX9, no testes can develop and the path is clear for the development of ovaries. Even so, the absence of the SRY gene or the silencing of the SOX9 gene are not enough to trigger sexual differentiation of a fetus in the female direction. A recent finding indicates that ovary development and maintenance is an active process, regulated by the expression of a "pro-female" gene, FOXL2. In an interview for the TimesOnline edition, study co-author Robin Lovell-Badge explained the significance of the discovery:
| “ | We take it for granted that we maintain the sex we are born with, including whether we have testes or ovaries. But this work shows that the activity of a single gene, FOXL2, is all that prevents adult ovary cells turning into cells found in testes. | ” |
Read more about this topic: XY Sex-determination System
Famous quotes containing the words studies, genetic, factors, influence, gender and/or traits:
“[B]y going to the College [William and Mary] I shall get a more universal Acquaintance, which may hereafter be serviceable to me; and I suppose I can pursue my Studies in the Greek and Latin as well there as here, and likewise learn something of the Mathematics.”
—Thomas Jefferson (1743–1826)
“We cannot think of a legitimate argument why ... whites and blacks need be affected by the knowledge that an aggregate difference in measured intelligence is genetic instead of environmental.... Given a chance, each clan ... will encounter the world with confidence in its own worth and, most importantly, will be unconcerned about comparing its accomplishments line-by-line with those of any other clan. This is wise ethnocentricism.”
—Richard Herrnstein (1930–1994)
“Girls tend to attribute their failures to factors such as lack of ability, while boys tend to attribute failure to specific factors, including teachers’ attitudes. Moreover, girls avoid situations in which failure is likely, whereas boys approach such situations as a challenge, indicating that failure differentially affects self-esteem.”
—Michael Lewis (late–20th-century)
“I am always glad to think that my education was, for the most part, informal, and had not the slightest reference to a future business career. It left me free and untrammeled to approach my business problems without the limiting influence of specific training.”
—Alice Foote MacDougall (1867–1945)
“Anthropologists have found that around the world whatever is considered “men’s work” is almost universally given higher status than “women’s work.” If in one culture it is men who build houses and women who make baskets, then that culture will see house-building as more important. In another culture, perhaps right next door, the reverse may be true, and basket- weaving will have higher social status than house-building.”
—Mary Stewart Van Leeuwen. Excerpted from, Gender Grace: Love, Work, and Parenting in a Changing World (1990)
“A man finds room in the few square inches of the face for the traits of all his ancestors; for the expression of all his history, and his wants.”
—Ralph Waldo Emerson (1803–1882)