scientific study about incest?

[drslump]

I was watching the news on TV today with my parents, the news talked about indian children with face malformations. The journalist explained that that disease was so common in India because their women have a lack of a vitamine or protein (I can't remember) and because they use to marry close relatives (incest).

I complained about that last reason because I've never believed in incest as cause of malformations (either in the body or the mind). My parents were convinced that it's of course the real cause. So we had a little argue about it.
I promissed them to find some scientific studies about the subject to know the truth.

I'm convinced that I'm right. Take for example a farmer who grows horses, once he finds a good horse he will make the horse have descendants with its own daughters, to keep the good blood line. He will do so until it starts to degenerate.
To me incest is one of those fears we have learnt from a very early age, probably because of religion.

Anyway, if someone could provide me with some links with scientifical studies about the subject, it'll be much apreciated.

thanks, ivan

[agallag]

I know there have been studies, but I wouldn't know where to start looking. As far as I recall, there can be issues with immediate family (parent/child or siblings), but cousins are no big deal. I believe it's even legal to marry your first cousin in Canada, for some strange reason...

[az]

I think I heard once that there are no problems with the first generation of inbred kids, just that the error accumulates and that this thus becomes more and more dangerous with every generation.

AZ

[Paddy]

It’s all down to the mode of inheritance of these congenital disorders.

Each of us possess many ‘defects’ in our genetic code which if activated will cause problems. 25or so are lethal, the rest will cause anything from severe physical deformity to mental retardation.

The reason that we don’t see these problems is because my ‘defects’ are different to yours. The closer your partner is to your own genetic structure, the more likely these defects will be common to the both parties. Therefore in consanguineous mating there is a significantly higher chance that one of these defects will be expressed in their offspring.

I am not a religious man, but the evolutionary advantages of such a process are obvious. If we are all genetically similar, then we all become susceptible to disease. For example, there are a population of prostitutes in Africa who do not become HIV positive despite recurrent exposure. Why is that? Because genetic diversity has randomly made them more resistant.

And yes farmers do try and breed out what they regard as poor characteristics from their livestock, but the have to introduce fresh blood or problems occur. It is easy to see in my fish tank. I can get a blue fish and a red fish and make them mate, but with every generation more and more ‘runts’ are produced.

Sorry if I am not making sense, or insulting your intelligence – it is not even 7am here. Let me know if you want anything more specific or in more detail.

[Paddy]

Anyway - wha'ts your sister like???

[az]

That was a nice explanation Paddy Thanks

AZ

[Brian Ellis]

Children resulting from incestual relationships are often normal, but the danger comes from inbreeding. There are many areas in the world where the population is such that no-one is farther away than first cousin of anyone else. These communities invariably degenerate into poor physical and intellectual beings and, in time, will die out. I seem to remember one such in one of the islands offshore from Holland.

Quote from Encyclopaedia Britannica:
From the social, as opposed to the individual, point of view, close inbreeding does not increase the number of deaths from recessive disease; it merely precipitates these so-called genetic deaths in earlier generations. In heterozygous form, with no adverse influence on the individual who carries them, such alleles contain the possibility of future deaths from recessive disease; and death for infant offspring of consanguineous parents reduces that possibility for the next generation. The principle of deliberate inbreeding is used with domestic animals to eliminate such covert recessive alleles from the stock. Nevertheless, there seem to be problems of health from very highly inbred "pure" lines, and heterozygosity in some alleles seems to be advantageous. Many species, including man, have been established by episodes of isolation and inbreeding interspersed with outbreeding; they apparently thrive in this way.

All human societies have some incest taboos. These are rules and laws that prohibit marriage or sexual relations, or both, between certain kinds of kin. The kinds of kin always include some consanguineous classes, and one theory of the establishment of incest laws is folk knowledge of undesirable inbreeding effects in offspring of such unions. Incest taboos are not uniform restrictions to a particular grade, however, and often extend to nonconsanguineous relations. Thus, in traditional Chinese society a man may marry his mother's brother's daughter, for instance, but he may not marry any person with his own surname. Other theories of the origin of incest, therefore, include analysis of its effects on stability of the family as an economic and educational unit and ascribe the definition of incest in various societies to social and psychological motives.
QUOTE ENDS

Drslump: really not recommended!

Finally: Incest makes the heart grow fonder

[Paddy]

Interesting read Brian!



I am a bit more awake now!

[Wombat]

Originally posted by Brian Ellis

Finally: Incest makes the heart grow fonder

I prefer:

"Because if you can't keep it in your pants, keep it in the family."

[GNEP]

"Incest is Best" does it for me

[CHHAS]

There's no breedin' like inbreedin'

[Wombat]

Originally posted by GNEP
"Incest is Best" does it for me

No, that's "Beastiality's Best <A HREF="http://www.gthhh.com/hymnal/song.asp?songno=1">(lyrics)</A>" Thank god for Canadian college drinking songs.

[Umfriend]

Perverts!

[GNEP]

Bestiality's Best? Canadian? I've always thought of it as more of an English Rugby song... (although a lot of the references are to antipodean animals)

[Paddy]

I wonder what Rolf has to say about it?