CCR5-Delta-32, the mutation with the really funky name

Sinclair DNA -The CCR5-Δ32 Mutation


There is an unusual mutation that may have left some of us with ancestors from Northwest Europe with the ability to resist certain diseases like West Nile Virus and AIDS. Any mutation that splits us up in more recent years than the R1b1c mutation is useful to better understand our path through time.

The geography of the mutation, plus the (much debated) dates of its occurrence in the human population, points to it being an overwhelming Norse mutation. It shows up very strongly in Norse countries and in those areas invaded by the Vikings.
MapBlackDeath
The spread of the Black Death was an event of monumental proportions in Western Europe. The fact that your ancestors survived is either the result of genetics or pure luck - likely the later. This map shows the spread of the disease.
The spread of The Great Pestilence.
Image: University of Minnesota

That map doesn't show some of the pockets which were able to resist the disease. Granted, these pockets were rare.

This theory regarding resistance to the Black Death is currently being much debated. with some saying "this is unlikely, given that the frequency of CCR5-Δ32 in Bronze Age samples is similar to that seen today." 137   This is one of the news reports which set the DNA world abuzz back in 2005, "Plagues 'caused HIV resistance 'The plagues of the Middle Ages have left about 10% of Europeans resistant to HIV, researchers have said."  Cooler heads have since prevailed and the mutation is being studied very carefully. One new bit of research is that having both sides of the mutation was believed to make you fully resistant to HIV. Now it's believed delay onset by about two years.

That new bit of press hasn't stopped the provisional historians. One, Hugh Montgomery, believes the mutation occurred back at the Tower of Babel and was carried north by 'The God-Kings of Europe' and went on to merge with the bloodline of Jesus and Mary. No need to let the incidental fact that the mutation is proven to have occurred in northern latitudes slow down the sale of books.

My concern with CCR5-(delta)32 is that it is bi-parentally inherited and may be reshuffled by recombination (I’ll explain this more below). As of this writing, I can’t find an expert anywhere who can explain how this mutation is passed from parents to children. I know that the child can end up with a +/- (half inherited) if only one of the parents has the mutation. As of this writing, I’m the only one in the project tested for the mutation. With a +/- result, I should be resistant to the West Nile Virus, but not necessarily to AIDS.

A mutation that is inherited by both parents, or in part by only one parent is potentially in danger of not being useful to a Y-DNA genealogy project. Our interest is primarily in tracing genealogy using a combination of the father-to-son inheritance of DNA, surnames and specific mutations.

The only way I can think to resolve this is to test my father, brothers and immediate family to look for the mutation or lack thereof and determine if my + came from my mother or father.

Two possibilities 

Dad +/-   (marries)  Woman -/-
            Son +/- (marries)  Woman -/-
                          Son +/- (marries)  Woman -/-
                                   My Father +/-  (marries) My Mother -/-
                                                        Me +/-

In this instance, the mutation is traveling only in the male line generation to generation and, un-reshuffled in each generation. This, plus YDNA, plus documents pointing back to Norse ancestry would mean we can use the  CCR5-(delta)32 mutation as a very viable way to prove our Norse ancestry.


(2)
Dad -/-  (marries)  Woman -/-
                 Son -/- (marries) Woman +/-
                                Son +/- (marries) Woman -/-
                                               My Father +/- (marries) My Mother -/-
                                                                    Me +/-

This could well be what happened with my results - a reshuffling. This would render the mutation useless to genetic genealogists tracing surname descent.

I had hoped to get a complete answer to all this before posting this website, but geneticists’ understanding of this mutation is still limited.  The folks I spoke to at FTDNA don’t seem to have satisfactory answers to the reshuffling question.
               
An article in Human Biology magazine explained this mutation this way - “The CCR5-[DELTA]32 mutation seems to have had its origin in northern Europe, but there is no agreement about its age, which varies from about 700 years ago (with a range of 275-1,875 years) (Stephens et al. 1998) to 5,075 years ago (with a range of 3,150 to 7,800 years) (Sabeti et al. 2005). Lucotte (2001) put forward the hypothesis of a Viking origin for the mutation, suggesting that the mutation already existed in Scandinavia before the Vikings dispersed 1,000-1,200 years ago. A study in Europe shows a high frequency of the CCR5-[DELTA]32 mutation in areas usually associated with Viking culture, namely, Iceland (14.7%) and Sweden (14.2%) (Lucotte 2001), with decreasing frequencies running toward southern Europe (Libert et al. 1998). This mutation is believed by some to be as old as 7,500 years. Another has postulated it may be as much as 127,000 years old. The consensus is the more recent age. In Europe the gene frequency of the CCR5-[DELTA]32 mutation is about 10%, resulting in a heterozygous frequency of 18% and a homozygous frequency of 1% (Martinson et al. 1997). The mutation's relatively high frequency in Europe has been explained by positive selection of this mutation in those affected by bubonic plague (Stephens et al. 1998), but Galvani and Slatkin (2003) demonstrated that smallpox is a better candidate for positive selection for the CCR5-[DELTA]32 mutation, thus explaining the cline prevailing today in Europe. HIV and poxvirus (responsible for smallpox) enter leukocytes by using...”  136

Next Steps for the CCR5-Delta-32 Mutation Study

It is critical that we test the members of the DYS390=23 group for CCR5-Delta-32. Given how little is still known, I'd never want to waste peoples' money on a test that may prove inconclusive, so I'll only test a few who already have the markers necessary to prove which SNP they're in. In other words, they must have the 67-marker test first. This testing will begin again shortly.





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