Can someone please explain to me why epigenetics doesn't partially validate Lamarck? I've been trying to make the counter argument in my head but can't

Epigenetics is expression of your genes based on chemical reactions in your body. Some genes are turned off (or more precisely, “hidden” by curling up around histones), others turn on (expose themselves so proteins can be made from their codons) at different times. That’s the nurture side of things. Lamarck says that if you gain a lot of muscle, or stretch everyday and become flexible, that your babies are predisposed to being more muscular or more flexible. However, that doesn’t get inherited. But what studies HAVE shown is that health makes a difference—there was a study that compared behaviors of fathers, and if they worked out regularly for 30 days before conception, had healthier sperm that meant their offspring were more likely to be healthy and fit as well. I wouldn’t call that epigenetics though, since epigenetics is more specific to expression of genes within an individual, and not the inheritance of the genes themselves

It's a fair argument. In fact, I think almost anyone would agree that it at least partially validates Lamarck - or invalidates him less. However, perhaps someone else has fault with how that oversimplifies both Lamarck's argument as well as the epigenome?

Thanks all, interesting responses. A1 - so at a high level: the exact characteristics are not inherited, which is what Lamarck's theory outlined. Rather, offspring are predisposed to the broader tendencies of parents. Broader tendencies are not technically epigenetics, which is why they are different. Does that sound right? P1 - thanks for some early morning gnomebuns 😂

I am excited about the work coming out with CRISPR/CAS9. It is going on I be a game changer for so many families

PwC - agreed. I want to transition to that field so badly