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Lamarkian inheritance -- not just a straw-man "mistake"? Answered

A new article in Nature reports on research indicating that developmental changes caused by environment can be passed on to offspring. The Universe is always more complex, and more subtle, then the textbooks and dogmatists would have you believe.

Lamarkian inheritance is a theory of genetics where animals could pass on traits which they acquired during life. In the typical textbook oversimplification, the examples used are often the giraffe stretching to reach leaves would have children with longer necks; the blacksmith who developed a highly muscled right arm would have childred with bigger right arms; and so on. After the discovery and rediscovery of Mendelian genetics, Lamarkism was more or less ignored (except by Lysenko), leaving only this simplistic and stupid story of a "mistaken idea" in textbooks.

There have been a number of discoveries in recent years of heritable traits (in humans as well as in other animals), for which no specific gene, or even combination of genes, could be isolated. The term "epigenetics" refers to the fact that many of our physical traits are driven, not by genes directly, but rather by the complex biochemistry of how, when, and how much genes are expressed.

There have been some examples of epigenetic inheritance, but in all those cases, the pattern of gene expression is itself driven by the presence or absence of nearby "triggering" DNA in the genome.

This new article is an example where an epigenetic feature driven by enviornmental influence appears to cause changes that can be passed on to offspring. What the mechanism is (i.e., how the pattern of expression gets "stored" in the germ cells) is not clear, but it is very intereresting to see the effect in real life.

Discussions

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Jaycub

10 years ago

I saw a show on PBS about epigenetics. It said that the amount of food your grandparents ate at cetain points in their developement has a significant impact on your lifespan.

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PKM

10 years ago

I see how physical traits can be driven by the environment altering how genes are expressed, but I'm wondering how that ties in with inheritance. People from the same ancestry living in sunnier places with express the gene for making melanin more, sure, but that's just a physical response to a stimulus, isn't it? This might be a tautology, but I thought the definition of heritable traits was that they came from the parents' genes in some form or other, and non-heritable ("nurture"?) traits were in response to the environment. Did you find any specific examples of environment-driven traits being passed on to offspring?

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kelseymhPKM

Reply 10 years ago

Hi, PKM. Your first paragraph hits the nail on the head. This is why this research result is so interesting! It seems to "violate" the dogma that (a) only genes are passed on, and (b) that environmentally-induced changes cannot be inherited. Stay tuned!

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Goodhart

10 years ago

It is like one geneticist said to me once concerning the gay gene search: "anyone looking to make these traits nature or nurture defined, is asking the wrong question"