[__ Science __ ] Epigenetics—Inheriting More Than Genes

[AIG.com]

All our lives, we’ve heard that our physical makeup is determined by our genes, not environment. But the science of epigenetics is forcing scientists to rethink their assumptions.

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[Barbarian]

He's a few decades behind. And epigenetics has gone far beyond what the author assumes. Genes can sometimes produce traits that not only make the organism more responsive to the environment, but can also pass on extra-genetic information to a succeeding generation or even more.

A useful trait. Which is why natural selection could favor such genes.

Aside from showing that the methylomes of ancient Bison are pretty similar to modern cows, their findings also proved the stability of methylated cytosines over long periods of time and show the first direct evidence that methylation patterns can be studied in the DNA from ancient specimens. So perhaps you don’t really need a time machine to study evolution as long as you do have a time capsule, like the Bison samples. In a newly released second study, Suter and colleagues studied several generations of genetically identical mice with an epiallele susceptible to methyl donors. The researchers found that with dietary supplements of methyl donors, the phenotype of this epiallele changed and that trait was passed on, and even became more prevalent in subsequent generations, as long as selection and the supplementation remained in effect. Once the dietary supplement and selective pressure was removed, the phenotypic changes remained for only a single generation before reverting back to their original state. This work is the first demonstration that selection for epigenetic traits can have cumulative, heritable effects in mammals and suggests an alternative to the notion that natural selection acts on genetic variation alone. Suter and her crew think this mechanism might be a way that species can rapidly adapt to new environmental conditions, like a change in available diet, and then even change back a few generations later if needed.
https://epigenie.com/epigenetics-at-the-intersection-of-environment-and-selection/

Evolution can work in surprising ways.

All our lives, we’ve heard that our physical makeup is determined by our genes, not environment.

That's not what biology teaches. Every organism is a result of genes and environment, and it's been like that since genetics was founded. Most people who think they hate evolution, don't know what it is.

 

[Truthfrees]

The sequence of DNA can be identical but produce different results based on the presence or absence of epigenetic markers. For example, identical twins have the same DNA sequence but can have different chemical tags leading one to be susceptible to certain diseases but not the other.
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cool

 

[Barbarian]

Actually, identical twins don't have the same DNA sequences...
Identical twins form from the same egg and get the same genetic material from their parents — but that doesn't mean they're genetically identical by the time they're born.

That's because so-called identical twins pick up genetic mutations in the womb, as their cells weave new strands of DNA and then split into more and more cells. On average, pairs of twins have genomes that differ by an average of 5.2 mutations that occur early in development, according to a new study.

"One particularly surprising observation is that in many twin pairs, some mutations are carried by nearly all cells in one twin but completely absent in the other," Ziyue Gao, an assistant professor of genetics at the University of Pennsylvania, who was not involved in the research, said in an email.

Identical twins don't share 100% of their DNA

Identical twins form from the same egg and get the same genetic material from their parents — but that doesn't mean they're genetically identical by the time they're born.

www.livescience.com

Not surprising that you can find differences. It is possible that they might have identical DNA, but the odds are against it.