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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."
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.
Article doesn't say what interactions the adult mice had with their offspring. The benefit may have just been passed to the next generation through regular learning, modeling, etc.
I don't know about lab mice, but rat packs have a pretty complicated social structure (for example nominating food tasters to try new sources of food) so I'd bet that mice can teach their young a lot more than researchers might suppose.
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.
Here's my personal suggested mechanism.
Enriched environments have long been known to make mice 'happier' in addition to being better at solving various tests, and having larger brains, etc. This stress-reducing effect has been known to be maintained long after the rats are removed from the enriched environment.
The change in the mother rats should fully be expected to be partially shared with the pups. The womb is not a completely separate environment that just happens to exist inside the mother, her experiences shape what sort of chemicals(beneficial or detrimental) are delivered to the baby.
A healthier, less stressed out mother is likely to nurture her babies properly while they're in utero, and uterine environment that's not bathed in stress hormones is generally a preferable one for the baby's neurological development.
TFA also mentions that an opposite effect occurs, where highly stressed mothers had babies that then also abused their pups tend to have pups that themselves are poorer mothers. They don't mention if problem solving tests were given to these rats, but I'd fully expect that they'd show deficits in tests of memory and intelligence.
The researchers in the article say that this is a completely shocking discovery, I'd be shocked if it didn't happen. The stress response affects not only the mother, but also the baby, and those changes can be noticed in their later lives. Quel surprise.
This is an unfortunate shortcoming of science at the moment. A tested result is rejected until there is a suggested mechanism; as soon as a mechanism is suggested, it is all too often treated as "true" even if the mechanism itself has never been experimentally tested at all but was just plucked out of the air. The one that instantly springs to mind is the 2005 result that being cold can after all make you susceptible to catching a cold. The paper is reasonable and itself admits that its "suggested mechanism" (that capillaries in the nose constrict, reducing access by the immune system) was not itself tested by the authors, but was just an idea they came up with when their actual experiment -- do people sitting around with their feet in bowls of icy water catch colds more often -- gave a positive result. Nonetheless, that mechanism very quickly started getting bandied around as if it were gospel.
I'm sorry, so the offspring of these mice stayed with the general population and their parents?
Couldn't this be an argument for nurture? Heck, just competing with other mice.
Like the youngest learning to eat first in some families...
I'm not convinced that there is anything even remotely of interest here.
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.
This is a crock of BS.
First, no one "deifies Darwin". Second, Lamarck is widely respected in France as the father of evolution, and that's exactly what he was. Ideas about evolution were bouncing around for a long time before Lamarck, but he was the first one to lay down an actually scientific theory of evolution. No educated biologist would "vilify Lamarck".
But the fact remains that he simply didn't get it right. He didn't figure out the branching tree of life, and he didn't figure out natural selection. "Inheritance of acquired characters" wasn't even an original Lamarckian contribution, he merely endorsed it as part of his theory, as did Darwin.
How is that a shortcoming of science?
1) The researches found a result.
2) Proposed a possible mechanism.
3) Stated the mechanism was untested and might just be bullshit they cooked up at the pub.
4) People misreport guess of researchers as "Fact!" ...
6) "Shortcoming of science!" (and profit?)
It's sort of like saying that the urban legand "People think we only use 10% of our brain even though research has shown this to be almost certainly false." is a shortcoming of science.
People talk. People like to have "all the answers". The problem is with gossip not science. 'Science' hasn't ruled on the subject yet. The official stance of 'science' is that the mechanism is unknown.
Just as 'science' has only found that mouse mothers subjected to certain conditions can pass along the effects to their children even after the conditions have ceased. The mechanism should be discovered before any other conclusions can be reached. The summary is attempting to assign far more consequence to the study than study can provide. The shortcoming is with vague and speculative reporting not science. /rant
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.
Interesting eh? So how did it explained religion?
Well it appears that proclivity for social interaction is acquired. PLus it is somthing you can pass on to others without genetics.
What's not quite clear to me here is if the children mice were separated from the adults at birth. if not then perhaps the adult mice just are passign on behaviours. if so then maybe there is some extra genetic means of passing things on at the cellualr level or perhaps mice in the womb can experience the behaviours of their parents.
For example, if the preacher droning or the choir singing somehow releases endorphins in the mother that increase blood flow to the fetus, perhaps an association with certain sensory input can be learned at the fetal level.
Some drink at the fountain of knowledge. Others just gargle.
That's only part of the story. The word "flammable" was introduced into American English, essentially by the government, specifically because safety regulators worried that the "in" prefix could confuse people. Etymologically speaking, "inflammable" means "capable of being inflamed". Of course, this relates to fire, but also bad tempers, and so on.
"Flammable" comes from the Latin verb "flamare" -- to set on fire. It was used by the English, but was basically abandoned until after WW2, when it gained acceptance in America.
http://www.write101.com/W.Tips215.htm
> 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.
Isn't it evolutionary advantageous for the offspring to adapt itself to the environment (the chemicals) it causes?
Individuals don't adapt, populations do.
Squirrel!
"This is an unfortunate shortcoming of science at the moment."
I agree with most of your post but disagree with your conclusion.
Contrary to the GP's claim there is no requirement in science for a "suggested mechanisim", the results of the experiment are far more important than the explaination. For example, nobody has yet explained gravity but few doubt it exists and that we can acurately predict it's behaviour via models.
However it is common practice for papers to offer (clearly labelled) speculation in the hope that "someone else" will look for evidence and cite your paper if they find it. A failure to understand the difference between clearly labeled speculation and repeatable experimental results is definitely a "shortcoming" but it is not a "shortcoming of science". Worse still the "shortcoming" of which you speak is often indistingushable from willfull ignorance.
"A tested result is rejected until there is a suggested mechanism" - This is simply false.
IMHO the "unfortunate shortcoming of science" is the apparent inability of it's philosophy to rate a mention in high school science classes. This is not due to a lack of trying, see: Sagan, Dawkins and Randi. My own SPECULATION as to why is it so, is that most people ( including the majority of educators ) simply want certainty and cannot accept a philosophy that shuns it, so the philosophy part is ignored and science becomes a library of factiods that are discovered via inspiration, rather than found via critical thinking.
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
So human mothers-to-be are genetically selected to want a strong, genetically healthy man to be the father of their children?
Yup. And that is why the things men commonly want in women can be easily connected to giving birth or taking of the child in physical attributes (nice breasts and hips) or good genes and good sociological standing in others (how fit someone is. Some cultures appreciate being well fit while others appreciate seeing that woman has had excess food - often the latter cultures seem to connect fat women to being good at giving birth, too).
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