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I am wondering whether a behavioral trait (e.g. fear or stress experienced in the lifetime of the parent) can be transmitted genetically to its offspring?

I understand that a behavioral tendency for stress acquired through evolutionary time can be transmitted from parent to child, but I'm wondering whether a trait not present before can be transmitted between 2 generations.

For example many studies claim that offsprings of holocaust survivors inherit psychopathological disorders. I'm wondering how this inheritance could occur genetically given such a short time period?

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You may want to have a look at: biology.stackexchange.com/questions/2875/… and en.wikipedia.org/wiki/Epigenetics – nico Jul 30 '12 at 17:34
    
great, thanks ! – DBR Jul 30 '12 at 17:43
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I think this is a duplicate of the question @nico mentions. In particular, the answer there completely solves this question. – Artem Kaznatcheev Jul 31 '12 at 4:09
    
This is a perfectly good question, but my answer linked above is relevant. The short version: it's not genetic; stress is transmitted hormonally from mother to child. – Richard Smith-Unna Jul 31 '12 at 8:38
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Vote to reopen - whilst the other question is similar, there are specific features related to the human case which warrant a separate answer (which I was just about to post when the Q was closed!) – Richard Smith-Unna Jul 31 '12 at 9:58

Strictly speaking no. There are ideas about cultural inheritance though that seem relevant here: see http://www.ncbi.nlm.nih.gov/pubmed/11425279. Cultural inheritance theory uses the plasticity of the human brain as the evidence for the underlying genetics of culture. I.e. we aren't born with the ability to speak English because our parents learned it but we have an the underlying brain structure that is controlled by genetics to learn cultural traits. It seems far more likely that the phenomenon you describe with holocaust survivors is more related to some environmental effects (from their parents) than anything genetic. In the comments stress hormones in pregnant mothers were mentioned. Any impact these have on the offspring are not truly "genetic", they're termed "maternal effects" in the evolution literature. In fact most selection studies go to great lengths to control for them or eliminate them. They aren't truly genetic because these traits would never get passed down to the grandoffspring of the original mother.

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I am just repeating @emhart answer but wanted to highlight the semantic.

There are several ways an individual can inherit from its parents.

  • Genetics
    • Through transmission of DNA. An acquired trait cannot affect DNA sequence directly and therefore cannot be inherited genetically by the offspring (this sentence is the answer to your question). Note however, that the environment in which an individual is found and the amount of stress an individual is experiencing may affect its mutation rate. But this has nothing to do with transmission of an acquired trait.
  • Non-genetics (or "environmental in the broad sense")
    • Environmental in a very narrow sense. For example, a dam that a beaver transmits to its offspring, a good habitat that the parents had to fight for. Note in the broad sense, any non-genetic inheritence should be considered as being part of the environment. Environmental change that an individual has caused (niche construction) of fighted for can potentially be inherited by the offspring
    • Cultural. For example a language, a method to hunt seals or a method to clean potatoes. Cultural modifications acquired by an individual can potentially transmitted to the offspring
    • Epigenetics. It includes any modification over the DNA and histones and any content of the egg. Something an individual has lived can affect the types of epigenetic modifications that a parent can transmit to its offspring.

Genetic and epigenetic characteristics can be exclusively transmitted from parent to offspring (setting aside horizontal gene transfer and transduction), while environmental characteristics and cultural characteristics can potentially inherited between any two individuals. In the field of population genetics, the ratio of the phenotypic variance that is due to (additive) genetic variance over the total phenotypic variance in a population is called heritability (in the narrow sense).

There are plenty of important keywords in my (and @emhart's) answer. You might want to have a look at the wikipedia entries for all these concepts. You might also want to have a look at this answer.

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