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Your Environment May Change Your Genes
An anonymous reader writes "Recent experiments indicate that your environment alters your genes. The longer identical twins live apart, the more their "epigenomes" (genetic sequences that activate or suppress other genes) differ. This possibility could cause a radical shift in the assumptions of biological inheritance (namely that, with minor exceptions, an individual's genes do not change), and indicates the possibility of return of Larmarckian inheritance which had formerly been consigned to the dustbin of biology."
The world will not get better through technology. We must seek to be better people.
Not completely irrelevant. Organisms may inherit features of the current state of gene expression from their parents. So even though the genome is unaltered by the environment, some inherited extra-genetic information is modified by the environment.
Doesn't it make you feel good to know that our freedoms are protected by politicans, lawyers and journalists.
A few points:
1) The issue here is methylation and demethylation of DNA sequences, not the submitter's "genetic sequences that activate or suppress other genes".
2) Methylation patterns are heritable through mitosis, so he's not necessarily wrong to say that genes are being "changed".
3) I forget the details of methylation in embryos, but most of it is wiped out between generations. In any case, sperm and egg cells are segregated very early on, so the environment should have minimal effect on changes that get passed along to offspring. The article doesn't address the issue at all.
I applaud the submitter's enthusiasm, as well as his not putting in the usual stupid, inflammatory question at the end. ("Could epigenetics mean the end of Microsoft?") But he could have cut back on the speculation a bit...
What I'm listening to now on Pandora...
4 billion years, 148,847,000 km of surface area, an astronomical amount of life per m, let that be a start to comprehension.
And don't forget that the genetic code is quite modular, so a single mutation could give you an extra arm, without the need to "re-evolute" the thing. Just to give a silly example. A better , real-life example is an extra nipple, some people have them.
Coincidentally, our fellow mammal species have a large variation in the number of nipples, so maybe it's not so strange that an extra nipple is more common than an extra eye? (Just thinking out loud). Maybe some genes are less protected against mutation than others?
"It's too bad that stupidity isn't painful." - Anton LaVey
"I think some people have fewer "religious" objections to evolution and more "it just doesn't seem possible" ones than most scientists would like to admit."
First, neither religiously motived reasons nor arguments from personal incredulity are valid arguments for the rejection of sound science. Second, spend some time online reading what people who reject evolutionary biology write. It's been a hobby of mine for quite a few years now, and in my experience the overwhelming majority reject evolution because of literalistic interpretations of the Bible. Third, this really isn't earthshattering news. At the University of Oregon we've got a professor working on DNA methylation for about the last 25 years or so--DNA methylation being part of the epigenetics mentioned in the article. It's long been known that the environment can alter DNA by methylating nucleotides which can alter gene expression, and that these methylation events can be inheritable. This is a minor addition on the IMHO already elegant theory of evolution--for a quickie look check out wikipedia's page on epigenetic inheritance.
It's important to note that one of the critical functions of DNA methylation is to control expression of genes involved in replication and tumor supression. It is thought that one of the reasons cancer becomes more likely as we age is that these methylation patterns are altered- a methyl group falls off of a promoter for a gene that spurs cell division, for instance, and now that gene is causing cells to divide out of control. That of course feeds into what this article mentions, that your enviroment can modify these methylation patterns.
An example of this is the hormone Insulin-Like Growth Factor-II. The gene that codes for IGF-II is "imprinted." The copy you get from your father is unmethylated, and is therefore expressed at the normal rate. The copy from your mother, however, normally has a methylated promoter sequence, and is therefore silenced. However, should something happen to that methylation, be it exposure to mutagens or simply your body screwing up as it copies this silenced gene, then the copy from your mother is turned on. You get a double dose of the growth promoter IGF-II, which makes it more likely cells will enter a phase of uncontrolled growth- cancer.
"FDA staff reviewers expressed concern about the number of patients who were left out of the study because they died."
Probably not exactly by this mechanism, but undoubtedly, there is a means of passing adjustments to environment on to our children. You don't need "science" to see that physical differentiation amongst peoples, differences that had extremely low occurrences before the differentiation, happens to quickly to be due to Darwinian selection. There has to be either a mechanism by which the parent's physical adjustments to extremes in their environment is being passed on or one by which adjustments that the parent does not have are caused in the children in response to the same extremes. In other words, their is an undiscovered adaptation "kit" that is being employed.
It is also becoming more obvious that there is a lot more "nature" learning going on in the brain than we previously thought. Recent experiments in which mathematical algorithms were used to decode information from more than one individual without change in the algorithms hold great potential for answering the question "when I see blue and you see blue, do we really see the same thing". If relatively high level mental faculties can be passed on, and there is some means by which environmentally induced adaptations can be made to the next generation, it would go a long way to explain things like radical differences in average population IQ (actually, more of a reallocation of mental resources towards the things that we revere as "IQ" today) that have been observed over the last 130 or so years.
An area that I think has the most potential (it fits best with what would solve the problem) and has had little exploration is the possibility of these adjustments occurring in the womb as opposed to at fertilization. Obviously, since only two cells are passed on from the parents, eggs and sperm are created after fertilization. There is thus a time, even in the case of eggs, for adjustments to be made to the genome after fertilization.
Note, that this still fits within the Darwinian concepts with only a minor adjustment. The adjustment is simply to include non-random mutations in the equation. This would in fact speed evolution up and increase its effectiveness.