Epigenetics: How our experiences affect our offspring

Oftencold · #1 (**permalink**) 03-10-2013, 07:12 AM

Epigenetics: How our experiences affect our offspring - The Week
January 20, 2013

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From Mendel and Darwin in the 19th century to Watson and Crick in the 20th, scientists have shown that chromosomes passed from parent to child form a genetic blueprint for development. But in a quiet scientific revolution, researchers have in recent years come to realize that genes aren't a fixed, predetermined program simply passed from one generation to the next. Instead, genes can be turned on and off by experiences and environment. What we eat, how much stress we undergo, and what toxins we're exposed to can all alter the genetic legacy we pass on to our children and even grandchildren. In this new science of "epigenetics," researchers are exploring how nature and nurture combine to cause behavior, traits, and illnesses that genes alone can't explain, ranging from sexual orientation to autism to cancer. "We were all brought up to think the genome was it," said Rockefeller University molecular biologist C. David Allis. "It's really been a watershed in understanding that there is something beyond the genome."

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Pregnant women who were traumatized at the World Trade Center on 9/11 were far more likely than other women to give birth to infants who reacted with unusual levels of fear and stress when faced with loud noises, unfamiliar people, or new foods.

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To the consternation of strict Darwinists, they can be. Researchers used to think that when a sperm and egg combined, all their epigenetic tags were erased, leaving the resulting embryo with a clean slate. Now they know that about 1 percent of our epigenetic tags escape erasure and pass directly to our offspring — and potentially their offspring and beyond. Scientists have discovered, for instance, that a group of children conceived during the Netherlands' desperate wartime famine of 1944–45 tended themselves to have smaller-than-usual offspring. That suggests that what men and women eat and smoke, and what toxins and traumas they're exposed to, can affect their children and even grandchildren. University of Texas zoologist David Crews has done multigenerational studies with rats that led him to speculate that soaring obesity and autism rates could be due to our grandparents' exposure to "the chemical revolution of the 1940s," including the introduction of new plastics, fertilizers, detergents, and pesticides.

Now this is interesting.

One of the first things that came to mind, and before anyone gets all excited, it's just a thought, is that in history homosexuality seems to wax and wane. We're all taught in school that this is because of religious bigotry and suppression naturally. (Religious authority potentially conflicts with State authority and the State runs most schools.)

So I Googled the topic. Shazam! Apparently this is a hot topic in genetic research that has not yet been suppressed out of political expediency.

http://www.the-scientist.com/?articl...omosexuality-/

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Researchers looking for a genetic signature of homosexuality have been barking up the wrong tree, according to a trio of researchers in the United States and Sweden. Instead, the scientists posit, epigenetic influences acting on androgen signaling in the brain may underlie sexual orientation. In a paper published last week (December 11) in The Quarterly Review of Biology, they propose a model describing how epigenetic markers that steer sexual development in males could promote homosexual orientation in females, and vice versa. The scientists offer their model to explain both the tendency of homosexuality to run in families, and the fact that so far no “homosexual gene” has been identified.

“It’s a very provocative, very interesting new twist that is plausible,” said Margaret McCarthy, a neuroscientist at the University of Maryland who studies how hormones influence brain development and was not involved in producing the model. But, she cautioned, so far the theory “is not supported by any data.”

Epigenetics Is A Critical Factor In Homosexuality

Epigenetics may be a critical factor contributing to homosexuality, study suggests

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According to the study, published online today in The Quarterly Review of Biology, sex-specific epi-marks, which normally do not pass between generations and are thus "erased," can lead to homosexuality when they escape erasure and are transmitted from father to daughter or mother to son.

From an evolutionary standpoint, homosexuality is a trait that would not be expected to develop and persist in the face of Darwinian natural selection. Homosexuality is nevertheless common for men and women in most cultures. Previous studies have shown that homosexuality runs in families, leading most researchers to presume a genetic underpinning of sexual preference. However, no major gene for homosexuality has been found despite numerous studies searching for a genetic connection.

sky dancer · #2 (**permalink**) 03-10-2013, 11:50 AM

I remember starting a thread about transgenerational trauma and it's impact and having people express that you shouldn't be blaming your ancestors for your problems. I took a ton of flack for that thread.

saltwn · #3 (**permalink**) 03-10-2013, 12:04 PM

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Originally Posted by sky dancer

I remember starting a thread about transgenerational trauma and it's impact and having people express that you shouldn't be blaming your ancestors for your problems. I took a ton of flack for that thread.

My daughter and I have discussed how we are similar in things apart from taught ritual and how we are like my mother. It's uncanny, there has to be a genetic basis is what I've always assumed.

Oftencold · #4 (**permalink**) 03-11-2013, 06:04 AM

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Originally Posted by sky dancer

I remember starting a thread about transgenerational trauma and it's impact and having people express that you shouldn't be blaming your ancestors for your problems. I took a ton of flack for that thread.

I think that it's a matter of perspective. People often forget that causality and culpability aren't the same thing.

For example, many people today suffer terribly from the effects of tobacco. Tobacco is a culturally embedded recreational drug largely because of the activities of our ancestors.

But since those ancestors presumably didn't know about the deleterious effects of tobacco, it is probably wrong to blame them for the results.

KnightOfSappho · #5 (**permalink**) 03-11-2013, 10:16 AM

Some movements and mannerism are certainly genetic but others are programmed in the womb as an adaptation to the local environment. That makes perfect evolutionary sense.

Also, I'm curious to know why research on epigenetics and homosexuality would be "suppressed for political expediency." It clearly supports the theory that a baby is programmed to be gay or straight before birth.

Lastly, it is foolish to NOT expect effects form trans-generational trauma. Parents may try to avoid passing down fears and anxieties but they get transmitted one way or another. Certainly part of that transmission does seem to happen before birth as well.

Interesting stuff.

Idealogically Promiscuous · #6 (**permalink**) 03-11-2013, 03:16 PM

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Originally Posted by Oftencold

Now this is interesting.One of the first things that came to mind, and before anyone gets all excited, it's just a thought, is that in history homosexuality seems to wax and wane. We're all taught in school that this is because of religious bigotry and suppression naturally. (Religious authority potentially conflicts with State authority and the State runs most schools.)

So I Googled the topic. Shazam! Apparently this is a hot topic in genetic research that has not yet been suppressed out of political expediency.

What possible political motivation would there be for suppressing that research? It identifies genetic culprits for turning on and off homosexuality in a person before they are even born. It also identifies environmental and nurture reasons for the same anomaly.

Seems to me it would satisfy both sides of the question.

faithful_servant · #7 (**permalink**) 03-11-2013, 03:28 PM

Quote:

Originally Posted by KnightOfSappho

Some movements and mannerism are certainly genetic but others are programmed in the womb as an adaptation to the local environment. That makes perfect evolutionary sense.

Also, I'm curious to know why research on epigenetics and homosexuality would be "suppressed for political expediency." It clearly supports the theory that a baby is programmed to be gay or straight before birth.

Lastly, it is foolish to NOT expect effects form trans-generational trauma. Parents may try to avoid passing down fears and anxieties but they get transmitted one way or another. Certainly part of that transmission does seem to happen before birth as well.

Interesting stuff.

AZRWinger · #8 (**permalink**) 03-11-2013, 04:14 PM

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Originally Posted by Idealogically Promiscuous

What possible political motivation would there be for suppressing that research? It identifies genetic culprits for turning on and off homosexuality in a person before they are even born. It also identifies environmental and nurture reasons for the same anomaly.

Seems to me it would satisfy both sides of the question.

Because if abortion is supported as a right, then the discovery of a genetic or epigenetic marker would lead to the abortion of gay children simply because of their sexual orientation. Abortion supporters would be confronted with a terrible dilemma if there was a test for homosexuality that could be administered to the unborn. Advocates for the unborn would prefer to avoid giving abortionists another reason to practice their trade.

Idealogically Promiscuous · #9 (**permalink**) 03-11-2013, 04:21 PM

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Originally Posted by AZRWinger

Because if abortion is supported as a right, then the discovery of a genetic or epigenetic marker would lead to the abortion of gay children simply because of their sexual orientation. Abortion supporters would be confronted with a terrible dilemma if there was a test for homosexuality that could be administered to the unborn. Advocates for the unborn would prefer to avoid giving abortionists another reason to practice their trade.

But the whole point of this research is that there can't be an absolute test for it since experience and environment come into play in switching on and off these genes. Plus, a gene hasn't been identified so there's no way to test for it.

Kizzume · #10 (**permalink**) 03-11-2013, 04:49 PM

Quote:

Originally Posted by Idealogically Promiscuous

What possible political motivation would there be for suppressing that research? It identifies genetic culprits for turning on and off homosexuality in a person before they are even born. It also identifies environmental and nurture reasons for the same anomaly.

Seems to me it would satisfy both sides of the question.

Remember, this is coming from the guy who says that ANY changing of our values in ANY way means that someone in power has more power now.

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