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Acquired Characteristics May Be Inheritable
A story from a week or so back in Technology Review describes research coming to the surprising conclusion that Jean-Baptiste Lamarck may have been right — that acquired characteristics can be passed on to offspring, at least in rodents. Lamarck's ideas have been controversial for 200 years, and dismissed in mainstream scientific thinking for nearly that long. "In Feig's study, mice genetically engineered to have memory problems were raised in an enriched environment — given toys, exercise, and social interaction — for two weeks during adolescence. The animals' memory improved... The mice were then returned to normal conditions, where they grew up and had offspring. This next generation of mice also had better memory, despite having the genetic defect and never having been exposed to the enriched environment."
something that explains religion...
It could be one day possible to create a kind of device that harmonizes human beings early on in childhood development, increasing their awareness and understandings.
The dangers of knowledge trigger emotional distress in human beings.
Lamarck is one of those guys who's name is generally synonymous with bad science (he's about as villified as Darwin is deified). I'm actually a bit (pleasantly) surprised that someone would invest the time into this sort of study.
That being said, the article is rather short in one important area: a suggested mechanism for this sort of inheritance. Without that, it's bound to be mired in controversy for some time.
Here's the actual article.
We're just learning that Histone/DNA modifications can be inherited.
Histones (the spools around which DNA is stored) tell when the DNA source code should be 'active' vs 'inactive'. And these histones have a huge data space in the form of possible modifications (methylation, acetylation, etc.).
When DNA is replicated, these histones too are replicated at the same time. And they seem to be replicated in a semiconserved manner similar to DNA (half go to 'old' strand, half go to 'new' strand). And that there is a whole series of touring-like proteins that can 'read' 'write' or 'erase' these modifications.
If these modifications are made during an organism's life, they can be inherited by offspring.
Not only is the code being copied, but the 'marks' that tell which/when/where to read the code at any given time/condition too can be passed down. And that these marks can be written in real time rather than waiting for mutations in the code itself.
There was a recent study that XO females who inherited the X from their father had markedly different dispositions than those who inherited the X from their mother. DNA modification that is unique to how the male or female deal with their own X chromosome could be being passed down to offspring.
Who's to say the enrichment caused this, lacking a control whose parents were NOT raised in an enriched environment? And if they did do a control (RTFA, yeah right), the explanation could simply be that the enriched environment resulted in a more healthy womb that the offspring grew in. Parents pass a lot more than just DNA to their offspring.
Read what grandparent says.
It's actually quite possible that epigenetic DNA modifications DO happen in these mice.
Females have all the eggs made before they're born, so how could the genetic material in them be affect by the conditions that the mother grew up in? Sperm DNA seems like it could be modified by the father according to living conditions, but it seems odd to think that environmental information in the brain would be passed down to the testes and such... It seems more plausible to think it's just the mice had a better mother.
Really, this is hardly a surprising result. There are many possible mechanisms that suggest themselves, operating either on the embryo or on the newborn - parents who are more intelligent are likely to be able to pass on more of what they've learned and/or provide a "richer" environment for their offspring, even if we're only talking about mice. The mammalian brain is remarkably plastic.
The real problem for the Lamarckian paradigm is that once you've optimized the environment, socialization, and gene expression for the animals in question, it's hard to propose a mechanism for making more radical changes through "acquired characteristics" - and in fact no such changes have been observed. This study does not change that fact.
The original article sounds to me to be altogether too credulous and sensationalistic.
From my internet knowledge I know that cancerous memes are passed from newfags to oldfags (e.g. Boxxy! U RAF U RUSE). This would appear to be the opposite direction to parents passing useful knowledge to their children.
echo -e 'global _start\n _start:\n mov eax, 2\n int 80h\n jmp _start' > a.asm; nasm a.asm -f elf; ld a.o -o a;
Doh, why didn't someone tell me that "inheritable" means "heritable"?
In Soviet Russia, Lamarckism as interpreted by Lysenko in agriculture, was the state mandated approach and genetics was essentially outlawed until the 1960s. Geneticists were fired from jobs, sent to work camps, prison or just executed.
Learning HOW to think is more important than learning WHAT to think.
This might be something like what zappepcs was remembering. I dimly recall reading similar research several years ago -- basically, the findings are that babies appear to be more aware of or interested in snake and spider shapes, but do not fear them until they've seen an adult express fear at them. A choice excerpt (emphasis mine):
Cheers,
"What in the name of Fats Waller is that?"
"A four-foot prune."
I really hope it's not the case that results can be rejected due to the lack of a mechanism to explain them.
Darwin had no mechanism to back his theory of 'origin of species by natural selection'. The mechanisms people had theorized at the time were not really compatible with Darwin's ideas. It wasn't till Mendel's work was appreciated that people had a viable mechanism for the inheritance that fit with Darwin's evolutionary theory.
> Does it really need one?
The great thing about comming up with a mechanism for this phenomenon would be that you could make predictions and come up with new experiments. To test the mechanism. For example, do both parents need to be in the enriched environment or is one of them enough (and if one is enough, does it matter if it is the mother or the father)? What happens when we take a fertilized egg from a rat from a boring environment and put it a rat from an interesting environment (or the other way round)?
A mechanism would make all kinds of (testable) predictions about the above questions. Once we have a mechanism we are beyond the 'we found a correlation' stage. Having said that I agree we can do without a mechanism for a little while longer. The results of a few more experiments in this area will make it much easier to come up with a mechanism.
So, Darwin's evolution is not the only evolution?
Great.That's the way of Science: correcting itself and rehabilitating ideas if they get proof.
Lamarck's theory didn't work, but it was a legit scientific theory nonetheless, in that it actually took the risk of telling us something about nature: right or wrong, nothing reduces the scientific rigor and dedication of Lamarck's work and his contribution to biology.
This is a legit revision of mainstream evolution theory, and has nothing to do with non-falsifiable, religious crap.
You're confusing a model with a mechanism.
We have no mechanism to explain gravity, but a wonderful model that handles it well enough to land us on mars. Mendel didn't have DNA and was able to make predictions and conduct his experiments just fine.
Required reading for internet skeptics
This was a common misconception until recently. You can read about it here.
I have seen so many people screaming "Lamarckism! Lamarck was right!" Because they want to imply "Darwin wrong!" or "Genetics wrong!" to generate a headline. While this stuff is interesting, it's not Lamarck. It's an interesting genetically controlled chemical phenomenon. It should have been expected. You evolve to deal with issues. You have chemical controls on DNA replication and interpretation. In shorter life span animals than humans, this can be a great advantage.
It ain't Lamarck. Lamarck says that if you cut off a tail of an animal, in generation after generation, after a while, the animal won't have a tail. Lamarck says that if a giraffe needs a longer neck to reach leaves, it will stretch upward and that act of stretching will make its children taller. And that change will go forth, generation after generation.
This stuff is vaguely like Lamarck, but it ain't Lamarck. People bring him into the conversation to get the uneducated excited. And at base, what they really want to say is "Darwin was wrong" because that gets dumb people really excited, which in turn sells newspapers -- now Darwin didn't say anything about mechanisms, so he's not wrong. And this new stuff doesn't tell us that anything about how we generally understand mechanisms is wrong. It's just that there's more. Well, that's fine. Go study that. Yes, we'll fund you. Shut up with the Lamarck crap.
As has probably been pointed out by slashdotters, as well as experts, concluding anything about the effect of a parent's environment to genes of the offspring is just plain dumb.
All they did was show that parents pass on what they have learned to their offspring. Don't know about you, but I already kind of realized this, as did the entire field of developmental psychology.
In order for me to conclude anything else, this is what the experiment must have looked like. There should be three groups of mice with the genetic defect, A B C. Group A should be the one "taught" to have better memory. Groups B and C should be left to develop normally. Fertilized eggs from group A should have been transplanted to females in group B. Group C should be left to reproduce naturally. Then, the offspring of groups B and C should be compared against each other. B's babies have any advantage over C's, then that is pretty much hard evidence that the genetic composition of the offspring of group A was somehow modified to reflect A's parents' development (without removing the original defect).
This would be hard evidence because A's offspring's environment would have had no chance to be affected by their parents, after birth OR in the womb.
I have to admit that I didn't make the effort to read the original article, and my comment is only a response to what some other commenters here seemed to conclude from it.
weinersmith