Consanguinity and miscegenation

Consanguinity refers to the degree of "blood" (genetic) relationship between two people, first cousins, second cousins etc.

Christian churches  have always had some prohibions against consanguinity in marriage.  At one time it was forbidden to marry even your 7th cousin, though more usually the prohibition stretched only to 4th cousin.  These days almost anything goes.  Only brother/sister relationships are really frowned on.  

From a geneticist's viewpoint, consanguinity prohibitions do have some benefit.  If a person has a genetic defect, such as a deformity, it is usually found in more than one member of a family.  But it is often the case that the defect is recessive, meaning that it only becomes visible in the progeny  if both partners to a marriage have it.  So marrying "out" reduces the chances of that happening.  

Another benefit  is "hybrid vigour", meaning that the progeny from quite different bloodlines are often more healthy, vigorous etc than either of the parent populations.  So consanguinity prohibions undoubtedly helped keep Christian populations healthy.

The scene is very different with Islam.  The laxity of Muslim divorce law means that a woman and her children have no security or protection from her marriage.  She can lose her marriage and any bebefits  it conveys in a matter of minutes.

So how does she get any security in her marriage?  She has to rely on social pressures, and family pressures in particular.  If her husband is her cousin and he tries to divorce her, both families will come down heavily on him with condemnations.  So that is why consanguinity in marriages, cousin marriages, is  very common in Muslim populations

And the genetic consequences follow as night follows day.  In Britain, almost all birth deformities presented to the NHS come from Muslim families. 

That is all reasonably well known but I want to extend the point a little further.  Mental abilities such as IQ are a brain function and the  brain is just another organ of the body. So cousin marriage should affect that too.   There should be a lot more poorly functioning  brains among Muslim populations.  Real bright sparks should be rarer.  And they are.  The average IQs in the Middle East are markedy lower than they are in Europe, around 90 compared to 100 in Europe.  So Muslims exemplify well the laws  of genetics.  Their failure to regulate consanguinity has dumbed them down and made them less fit generally on average.

So how does that affect interracial marriage or "miscegenation"? It should in theory be an extreme example of the benefit of avoiding consanguinity. The progeny of such unions should display hybrid vigour.  And  I have seen many rather obvious examples of that happening -- where one of the parents is East Asian, usually Chinese.  I have often seen good-looking and very capable offspring from such unions.  Australia's population is about 5% Chinese by ancestry and young Chinese-origin  women often choose Caucasian men as partners, almost invariably tall ones, so Eurasian children are common.  I have written at some length on Eurasians  in Australia below:

http://jonjayray.com/eurasian.html

But now we come to the tricky one: black/white  marriages. Miscegenation was historically forbidden in America but the grounds for the ban are not entirely clear. There was a clear belief that whites were superior in many ways so mixed race chidren were undoutedly regarded as inferior, but in what way was not systematically argued. Should not mixed race children benefit from hybrid vigour?

It would seem that they have done.  The term "black" is very loosely used in America today  -- covering skin tones from almost Mediterranean to literally black  And in the "black" population, lighter skinned blacks cruise. They are generally looked up to by other "blacks".  They are more prestigious.  And part of that prestige is probably fairly earned.  They probably really are healthier and more capable.  But it is a topic that would be too fraught to study systematically.  I have probably said too much already

But, as even the APA has conceded, the black/white gap in average IQ in America is still large.  The APA has put it as one standard deviation, which is a lot.  The gap is even greater if we consider blacks back in Africa so miscegenation in America has reduced the average black/white IQ gap but not by a lot.

But however you look at it miscegenation has been BENEFICIAL

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