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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."
I'll be interested when my environment can change my jeans... I'm lazy...
-FL
You've misrepresenting what the article says: Environment alters gene EXPRESSION, not genes. That makes the whole "Lamarckian" inheritance comment irrelevant, too.
The world will not get better through technology. We must seek to be better people.
If your environment is a radioactive waste dump you can be damn sure it will change your DNA.
The GeekNights podcast is going strong. Listen!
This really shouldn't come as a big surprise. Differential gene expression is one of the major unexplored areas of genomics, and we're just beginning to scratch the surface of how organisms as complex as humans can develop with a number of genes comparable to that of a roundworm. Changes in the environment controlling gene expression is something that's well documented in many different organisms.
You just need to learn more statistics.
Just imagine.
10 out of 100000 organisms get a light sensor.
They are better, so they become dominant.
Of the mutant offspring, lots do have a tendency to develop more than one light sensor.
More light sensors are better than one.
Now you have a fly-like eye.
Focusing lenses are easy.
The sensor must be protected by something, because it doesn't work otherwise, and the clearer the better, and those who have better focusing clear flesh covers for their eyes, can sense better their environment, and find better partners.
What you view as a huge advantage, can be broken into lots of incremental advantages that are easily explained by evolution.
Of course, it's almost magical that evolution can happen just by birth and death.
You never stop to think that all the tasks a modern computer can perform are just the result of the arrangement of "nand" gates, but there's no magic, and we understand it, because it's simple enough to be understood.
For evolution, it has the advantage of thousands of millions of years of incremental design.
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."
I didn't say they were valid arguments. When I said "my problem", I fully acknowledged it was MY problem with evolution, not a grand theory refuting it. I think that many scientists would prefer to think that the reason some people don't accept evolution is religion. I have read what people have written about elvolution though clearly not as much as you. While agree that the majority do harp on the creationist view, I think there are some who have some concerns about the theory itself. How valid those concerns are obiously varies but I am sure the work of past critics has been used to improve our current understanding. As I have said in a previous post the theory of evolution has itself evolved extensively over time (Unless you think Darwin hit it on the nose with the first swing). Your professor's research is 25 years old at most, so it will take a few more years for its implications to to sink into the general populace's understanding of evolution. Your not-so-humble-opinion seems to be based in years of studying the subject, maybe you can see how those of us who have not devoted the same amount of time to the subject have a slightly fuzzier view.
Insert pithy comment here.
Gene Hackman: Jailed as a teen in 1946 for stealing candy & soda pop from a convenience store now lives a wealthy life in New Mexico.
What's causing the mutation: With more than 70 movies to date, strong light sources constantly shining on his forehead can be traced as the culprit.
Demitria Gene , a.k.a. Demi Moore: From spending her minimum-wage hard-earned money with coke to earning $12,500,000 per movie and dating a kid who could be her grandson.
What's causing the mutation: Not really sure... Could be frequent exposures of her bare body to the cameras or the many plastic surgeries she had done.
Uncopyrightable: The longest word you can write without repeating a letter.
1 in 40,000,000,000 is all that is needed, since that special 1 is who will survive and replace the other 40,000,000,000. Useful features develop in paralel, and there weren't many before sexual reproduction (the history of life is mainly that of single cell bacteria for a long, long time).
Also natural selection does not explain evolution. Natural selection + variation does. Natural selection can't change a species if all the individual to select from are identical.
The fossil record has plenty of holes in it and can't explain ALL changes, but what remains does show enough clear transitions and failed combinations to support that theory.
Singularity: a belief in the "God" idea with the "demiurge" relation inverted.
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.
There's another far more powerful effect going on in evolution that people rarely hear about in the common explanations of evolution. The common explanation of evolution is as a sequence of individual beneficial mutations, like climbing a ladder. If that's how it worked then critics would be right, evolution would not have been able to produce the incredible variation and complexity we see today. That kind of advancement is about the least powerful mechanism in evolution.
In fact I'll even assume that every single mutation that occurs is either neutral or harmful and we'll still get the real and powerful mechanism of evolution. I'll give a relatively brief and superficial explanation, but it's a huge topic and this is still going to be fairly long.
A good place to start is with the common complaint of creationists that mutation and evolution "cannot create information". Well in the initial mutation phase they are right. When a mutation occurs it introduces noise, it tends to degrade information. But look what happens the moment that mutation gets passed on to an offspring. That mutation is now no longer random noise, it now carries a small bit on information. It carries a little tag saying "this is a nonfatal mutation". The presence of this mutation in the offspring is new created information, the discovery living record of a new nonfatal mutation. Over time the population builds up a LIBRARY of nonfatal mutations. This library is a vast accumulation of new information.
That information actually undergoes even more processing and synthesis. Over generations beneficial mutations would obviously multiply, but we're assuming there are none of those here. However entirely neutral mutations will also tend to accumulate and multiply. Nearly harmless mutations would also accumulate and multiply to a lesser extent. Somewhat harmful mutations will even accumulate, and extremely harmful-but-nonfatal mutations will pop up and disappear at the rarest frequencies. So not only do we build up a library of nonfatal mutations, the mutations get tagged with a tagged with a frequency, the percentage of the population carrying that mutation. Each mutation is tagged with a measurement. Every mutation now carries a cost/benefit information tag at the population level. The best ones have a high percentage representation and the most harmful ones have a near zero representation percentage. Our library now contains far more valuable and sophisticated newly created information.
The individuals in the population are on average going to carry a roughly stable load of harmful mutations, a roughly constant "cost" in harmful mutations. Individuals loaded with more than the average cost are generally going to die and remove a more-than-average load of harm out of the population pushing the average up, and individuals with a less than average load will multiply and pull the population average upwards. The cleansing effect of selection removing "damage" from the gene pool will automatically scale to offset the exact rate that mutation is causing "damage". Harm/cost/damage will be weeded out by selection at the same rate it is added by mutation. Neutral mutations will steadily accumulate in the library, and negative mutations will remain at a roughly fixed level constantly measured and scaled by the cost of each. Some mutations will dissappear while new ones appear.
The real power in evolution is the recombination. Every offspring contains a random mixture of mutations from that library. every offspring is a test case searching for a jackpot beneficial combination of mutations. Lets assume an individual has a million random mutations across its entire code. There are 500,000,000,000 mutation-pairs being simultaneously tested within that individual in parallel. Perhaps one is a mutation creating a toxin and another mutation for mutant skin pores. Either mutation alone may be harmful, but the pairing could be breakthrough protecting against predators.
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