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I apologize if this hypothesis sounds strange by I was wondering if any research had been done on a phenomenon which I've seen and have corroborated with many other - the idea that over time spouses tend to start looking similar to each other.

My hypothesis is that this is really a one-way street with the wife tending to look more like the husband. The reason being that after coitus her body is flooded with his genetic material which may lead to some mixing of DNA outside of the egg. Furthermore once the woman is pregnant she enter into a symbiotic relationship with an organism whose DNA is approximately 50% foreign. Her body must then adapt to the presence of that new genetic material.

I realize this may sound strange and Lamarkian but I was curious if the phenomenon itself had been investigated.

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While battling between Lamarkians and Darwinists, this sure has been investigated some time. The answer is: no. There are a lot of factors beside genes that can be a reason for this. First of all: our psychological reception of spouses. I, for example, tend to see similarities developing in people and their dogs over time. I am very sure they never ever share genetic material. – skymningen Sep 17 '13 at 13:40
@skymninge i can show you images of couples you've never met. At their wedding they look a certain way, 20 years later they look strikingly similar to each other. From what I understand genetic change within one's own lifetime has not really been conclusively resolved. – user4481 Sep 17 '13 at 13:55
I did not say, that I don't see those similarities. I see them quite often, EVEN between people and their dogs. But I would never account them to a genetic cause. – skymningen Sep 17 '13 at 14:31
I get that this is a legit question, but you are so sexist in formulating it I hope you never write again. – jkadlubowska Sep 18 '13 at 15:45
up vote 5 down vote accepted

Microchimerism (Mc) is an interesting concept, and

refers to the harboring of a small number of cells (or DNA) that originated in a different individual. Naturally acquired Mc derives primarily from maternal cells in her progeny, or cells of fetal origin in women.

In women, it has nothing to do with transfer during/after sex but rather is due to the presence of the developing fetus. There is definite long-term persistence of microchimerism, although not much is yet known about its effects. Here is a nice and free review from 2010 dealing with the subject. Most if not all of the effects have to do with immune function, in particular autoimmunity. It is definitely not a mechanism by which couples begin to look similar. That is social, in particular a result of living in the same environment with similar activities and tastes. Male contribution to cellular content in the embryo is almost nil, as sperm die and the transcript count in the successful sperm is puny compared to the egg. Most RNA content in the embryo is maternal until it switches to embryo.

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Terrific, this is just what I was looking for. Very helpful and very interesting. – user4481 Sep 17 '13 at 14:22
@user4481 There was an interesting article in Scientific American called " Your cells are my cells " by J Lee Nelson.Just google the title. – biogirl Sep 17 '13 at 17:28
The actual article is behind a paywall, here's a pdf. It's a great summary for sure. – Amory Sep 17 '13 at 20:28

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