A number of epigenetic studies suggest the existence of non-mendelian mode of inheritance. One of the more fascinating findings is the observation that exposure of mice to an enriched environments not only enhances long-term potentiation (a mechanism involved of memory formation), but also enhances LTP in their offspring during early adolescence, even if they do not experience an enriched environment themselves:

 

The Journal of Neuroscience, February 4, 2009, 29(5):1496-1502; doi:10.1523/JNEUROSCI.5057-08.2009

 

Transgenerational Rescue of a Genetic Defect in Long-Term Potentiation and Memory Formation by Juvenile Enrichment

 

Junko A. Arai, Shaomin Li, Dean M. Hartley, and Larry A. Feig

Wouldn't conditions inside the mummy mouse be an "enriched environment" wrt the offspring?

I am not sure what if we mean the same with enriched. What the authors describe is an environment where there are novel objects to explore, social interactions etc. I assume that these kinds of interactions are kind of limited inside the uterus.

Do we know how these enriched environments affect stress (and other) hormone productions inside a gestating mother?

 

Perhaps that's the reason, hormones created in response to the environment, affecting foetal development.

Edited March 31, 200916 yr by Transdecimal
I forget if it's "effect" or "affect".

I think that they'd have to transplant the embryo to a non-enriched mouse to rule out eg hormonal differences of the enriched mothers.

 

Epigenetics is cool.

Well, this is kind the point of lamarckian-type of inheritance, isn't it? Not necessarily hormones, but something is passed on from mother to child which is not purely mendelian genetics.

Well yes, but in Lamarckiansim isn't there also the requirement for the changes in the offspring to be inheritable to their offspring? That won't be seen if they have just undergone developmental alterations due to conditions inside the mother. The study needs to be extended to the next generation, surely?

Not necessarily. In the simplest sense it just means that life experience can be inherited to the offspring. The offspring itself may modify that according to their own life experience and pass that on. If it wasn't changeable after the first acquisition we would switch to Mendelian inheritance again.

The paper seems to point to an induction of LTP with a "cAMP/p38 MAP kinase-dependent signaling cascade". Can we apply this study to humans without becoming proto-eugenicists?