What is Epigenetics?
The modern view
In biology today, epigenetics has two closely related meanings:
- The study of the processes involved in the unfolding development of an organism. This includes phenomena such as X chromosome inactivation in mammalian females, and gene silencing within an organism.
What I am getting out of these meanings is that epigenetics is the study of
- Watching an organism develop without any interference and
- Changes that occur of gene function which a child inherits from two parents (male and female) including supplements a parent might take prior to conception.
I have not taken any medical classes of any sort so my interpretations may be way off and just a layman's interpretation of what I read.
On to the study:
Apparently there is a study indicating that there is a possibility of homosexuality through the study of Epigenetics due to "sex-specific epi-marks" not being erased.
Per 1st Article by ScienceDaily:
"Researchers at the University of Tennessee, Knoxville, say they've found a clue that may unlock the mystery. It lies in something called epi-genetics -- how gene expression is regulated by temporary switches.
Per 2nd Article by ScienceDaily:
"According to the study, published...in The QuarterlyReview of Biology, sex-specific epi-marks, which are "erased" and thus normally do not pass between generations, can lead to homosexuality when they escape erasure and are transmitted from father to daughter or mother to son."
"Previous studies have shown that homosexuality runs in families, leading most researchers to presume a genetic underpinning of sexual preference," said Sergey Gavrilets, paper co-author, joint professor of math and ecology and evolutionary biology and NIMBioS's associate director for scientific activities. "However, no major gene for homosexuality has been found despite numerous studies searching for a genetic connection."
Epi-marks may be the trigger they've been searching for.
Personally, I think homosexuality running in families and just being exposed to it on a daily basis could allow family members to be more accepting of the sexual preference, but not necessarily be a deciding factor as to whether they see themselves as homosexual. At the same time I think the study is saying that it is possible to inherit the epi-marks of non-erasure from one generation to the next.
Epi-marks constitute an extra layer of information attached to our genes' backbones that regulates their expression. While genes hold the instructions, epi-marks direct how those instructions are carried out. They are usually produced anew each generation, but recent evidence demonstrates that they sometimes carry over between generations.
Sex-specific epi-marks produced in early fetal development protect each sex from the substantial natural variation in testosterone that occurs during later fetal development. Different epi-marks protect different sex-specific traits from being masculinized or feminized.
One of the things that was mentioned in glancing over the abstract of the original paper was that they thought vitamins might play into the factor of how epi-marks perform.
So how was this study conducted?
"A working group at the National Institute for Mathematical and Biological Synthesis (NIMBioS), based at UT, used mathematical modeling that found the transmission of sex-specific epi-marks may signal homosexuality."
In the current study, researchers from the Working Group on Intragenomic Conflict at the National Institute for Mathematical and Biological Synthesis (NIMBioS) integrated evolutionary theory with recent advances in the molecular regulation of gene expression and androgen-dependent sexual development to produce a biological and mathematical model that delineates the role of epigenetics in homosexuality.
"Transmission of sexually antagonistic epi-marks between generations is the most plausible evolutionary mechanism of the phenomenon of human homosexuality," said Gavrilets.
"We discovered when these epi-marks are transmitted across generations from fathers to daughters or mothers to sons, they may cause reversed effects, such as the feminization of some traits in sons, such as sexual preference, and similarly a partial masculinization of daughters," said Gavrilets.
"The study solves the evolutionary riddle of homosexuality, finding that 'sexually antagonistic' epi-marks, which normally protect parents from natural variation in sex hormone levels during fetal development, sometimes carry over across generations and cause homosexuality in opposite-sex offspring," said Gavrilets
The mathematical modeling demonstrates that gene coding for these epi-marks can easily spread in the population because they always increase the fitness of the parent but only rarely escape erasure and reduce fitness in offspring.
In reading the various articles on this study, it seems to me that science should continue to research and study the epi-marks of epigenetics as it relates to all sexual preferences not just homosexuality. We might learn a lot more than we thought in other areas of human development.
If anyone is interested, here is a link to the detailed paper
****1st Article by ScienceDaily - "Epigenetics May Underlie Homosexuality, Study Finds"
"University of Tennessee (2012, December 11). Epigenetics may underlie homosexuality, study finds. ScienceDaily. Retrieved January 31, 2013, from http://www.sciencedaily.com /releases/2012/12/121211101832.htm"
****2nd Article by ScienceDaily - "Epigenetics May Be a Critical Factor Contributing to Homosexuality, Study Suggests"
"National Institute for Mathematical and Biological Synthesis (NIMBioS) (2012, December 11). Epigenetics may be a critical factor contributing to homosexuality, study suggests. ScienceDaily. Retrieved January 31, 2013, from http://www.sciencedaily.com /releases/2012/12/121211083212.htm"
Links used in this article that were not in either of ScienceDaily's articles:
****Authors of the 27-page paper "HOMOSEXUALITY AS A CONSEQUENCE OF EPIGENETICALLY CANALIZED SEXUAL DEVELOPMENT" published in "The Quarterly Review of Biology", December 2012, Vol. 87, No. 4:
------William R. Rice, Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, California 93106 USA
------Sergey Gavrilets, Department of Ecology and Evolutionary Biology and Department of Mathematics, National Institute for Mathematical and Biological Synthesis, University of Tennessee, Knoxville, Tennessee 37996 USA
****Bio-Medicine's website http://www.bio-medicine.org/
****Epigenetics Definition - http://www.bio-medicine.org/biology-definition/Epigenetics/
****Heritable Definition - Oxford Dictionaries http://oxforddictionaries.com/us/definition/american_english/heritable?q=heritable
****"The Quarterly Review of Biology" http://www.press.uchicago.edu/ucp/journals/journal/qrb.html
****Official Paper Abstract http://www.ncbi.nlm.nih.gov/pubmed/12861015?report=abstract
****Official Paper on the scientific study of Epi-marks http://ilsimplicissimus2.files.wordpress.com/2012/12/homosexuality.pdf
Links used in Credits not in any of the articles:
****Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, California http://www.eemb.ucsb.edu/
****Department of Evolutionary Biology, Uppsala University, Norbyvägen 18D, 752 36 Uppsala, Sweden http://www.ebc.uu.se/Research/IEG/evbiol/?languageId=1
****Department of Ecology and Evolutionary Biology (http://eeb.bio.utk.edu/) and Department of Mathematics (http://www.math.utk.edu/), National Institute for Mathematical and Biological Synthesis, University of Tennessee (http://www.utk.edu/), Knoxville, Tennessee