lemit said:
Epigenetics fascinates me.. . .
Who knows, maybe something I read here will change me in a genetic way. (Maybe that's stretching it a little. But then, if something is stretched far enough . . . )
--lemit
LOL
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Epigenetics might not be so new after all.
yes some see it as Lamark's revenge!
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In his most controversial experiment, Kammerer forced midwife toads, a species that lives and mates on land, to live in water. Their offspring preferred to live and mate in water and by the third generation he noted that they began to develop black nuptial pads on their forelimbs, a feature common to water dwelling species.
In 1926 Kammerer fell into disgrace when it was found that his only remaining fixed specimen had been injected with India ink to produce the appearance of the black nuptial pads. Kammerer's own role in the alleged fraud has never been proven. . .
. . .
Kammerer reported hybrid crosses of treated and untreated toads in which 'parent-of-origin effects' can be observed, a recurrent phenomenon in epigenetics.
Intersting link freeztar, never heard of the guy.
There are a few good links on that page too
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Rethinking The Genetic Theory Of Inheritance: Heritability May Not Be Limited To DNA
ScienceDaily (Jan. 20, 2009) — Scientists at the Centre for Addiction and Mental Health (CAMH) have detected evidence that DNA may not be the only carrier of heritable information; a secondary molecular mechanism called epigenetics may also account for some inherited traits and diseases. These findings challenge the fundamental principles of genetics and inheritance, and potentially provide a new insight into the primary causes of human diseases.
http://www.scienceda...90118200632.htm
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Germ cells carry the epigenetic benefits of grandmother's diet
Craig A. Cooney*
Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205
Environmental influences on epigenetics are important for understanding the mechanisms and inheritance of biological variation. Some of the best models for mammalian epigenetics are the yellow alleles of agouti in mice. Alleles such as Avy produce readily distinguished agouti, yellow, and mottled coat-color epigenetic phenotypes. Dietary and genetic variations during development affect the epigenetic phenotypes of offspring (1, 2). Little is known regarding the gestational timing of dietary treatments to affect epigenetics. Although the epigenetic phenotype is partially maternally, and grandmaternally, inherited (1, 3, 4), transgenerational effects of grandmaternal diets have not been reported. In this issue of PNAS, Cropley et al. (5) report the effects of specific timing of maternal dietary methyl supplementation on the coat color of offspring. Surprisingly, they find that maternal supplementation only during midgestation substantially affects offspring coat color. Importantly, they also find that this effect is inherited by the next generation, presumably through germ-line modifications during grandmaternal supplementation.
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. . .Lots of technical biology)
DNA methylation
There is also a grandmaternal effect on inheritance. That is, when mother and grandmother are fully agouti, a higher proportion of offspring have fully agouti coats than when the grandmother has a mottled or yellow phenotype (4). However, the effect of grandmaternal methyl supplementation was unknown. To answer this question,. . .
. . . These results demonstrate a transgenerational effect of maternal diet on the F2 generation, and they suggest a mechanism, namely modification of the F1 germ line. The degree of change in offspring phenotype was similar in the F1 and F2 generations, indicating that germ-line Avy silencing may be well maintained through gametogenesis, fertilization, and development. Theirs is the first demonstration that a germ-line epigenetic change can be induced at a specific gene. They provide a mechanism for transgenerational epigenetic effects.
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. . .. Other grandmaternal effects that appear to be epigenetic include diabetes in rats and humans. Transgenerational diabetes (F1 and F2 generations) can be induced by infusing pregnant rats (P1) with glucose during the last week of pregnancy (third trimester) (15). In humans, maternal (F1) and grandmaternal (P1) non-insulin-dependent diabetes mellitus (NIDDM) is associated with gestational diabetes (F2) (16). At least some of these models involve the recapitulation of epigenetic silencing in each generation (e.g., based on maternal behavior toward offspring; ref. 14) and probably do not require the tenacity of silencing evident in Avy.
Epigenetics at particular loci may have evolved to provide a range of phenotypes to suit a range of environmental conditions.
We do not know what range of phenotypes to expect when epigenetic systems that evolved over millions of years respond to new environmental variables such as refined foods, drugs, and xenobiotics. Glucose (15–17) and endocrine disrupters (18) are examples of factors leading to apparent epigenetic transgenerational effects in mammals; however, the genes responsible for the effects are not known. Now Cropley et al. (5) show that methyl donors have transgenerational effects attributed to a known allele, Avy.
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In humans, the possibility, even the likelihood, that grandmaternal diets contributed to the incidence of obesity and diabetes in the current generation and that today's dietary habits will have effects for generations to come make the work of Cropley et al. (5) especially important.
Their demonstration of a transgenerational effect of midgestational maternal methyl supplementation is a significant advance that should stimulate much needed research in this area.
Germ cells carry the epigenetic benefits of grandmother's diet
Bit of a heavy article to start sorry it just popped on my screen for some bizzare reason.
Given the "English' diet of my forbears it is lucky i am alive at all. Mum used to boil greens for an hour then, when they had lost all their colour, she would add a teaspoon of bi-carb (which i loathed) to "green them back up"!! Might as well eat cardboard.
PS (thinks) At least two generations of (mainly paternal) alcoholics too. Gives one pause.. . .
Both father and grandfathers produced offspring after a world war. I wonder what Wars do to inheritance?
methylation is an important word, I can't remember why