Black Americans' Ancestors

[J842P]

Rape most certainly does still happen, indeed it's rate is currently on the increase. It is considerably more likely that a socially disadvantaged person will be the victim of rape. Race is a common factor, there are others such as wealth, age, and sexual/gender identity. Rape is an act of violence, not attraction.

"What should have happened" is up for debate, but you would have to change a lot more things than the Transatlantic slave trade to substantially reduce genetic diversity in the Americas, already interestingly complicated by other political traumas and economic migrations.

He is talking specifically about the rapes of slaves by slave owners. That happened in the past.

Why is it so difficult to understand such a straight-forward statement?

You may be, but he is not, if by "he" you mean lpetrich. The original post cites this as a possible reason for the correlation, but does not stop there, nor should we. Racial violence and coercion is not and has never been strictly bounded by the current legal status of slavery. Indeed, I doubt very much that a black woman in 1890 felt at all more free to prevent or report a rape by a white man than her counterpart in 1820 would have; either way, the crime would be almost certainly impossible for her to prevent or gain legal redress for. We gain nothing by trying to whitewash the cruelties of our national history, or paint triumphal narratives of wholesale moral victories over realities that were much more grim for those actually involved with them.

No, I'm talking about Unter. No one is trying to white wash our history, least of all Unter.

 

[Sarpedon]

This is kind of an exciting time. For decades, African-Americans trying to trace their lineage hit a wall with slavery and lack of records. With gene sequencing, we could very well someday be able to identify (though not name) individuals brought from Africa, where they came from and who are their descendants. That would be immensely satisfying.

 

[Bomb#20]

Show your work.

Granting that mating was assortative and the population did not achieve Hardy Weinberg equilibrium, how do you figure it is physiologically possible for people to have tended to breed with others who were more white, and less so with people who were darker? What, was the darker member of an act of copulation breeding while the lighter member of that same act was remaining childless?


It's certainly likely that being black reduced one's odds of reproducing, but that doesn't change the fact that an interracial coupling doesn't change the ratio of black to white alleles in the gene pool.

I think I don't understand what you are saying, because it sounds to me like you are saying that it is impossible for darker or lighter skin to evolve in a population over time, whether it be by natural or sexual selection.

Wow. How did you get that out of what I wrote? Of course they can evolve by natural or sexual selection.

Anyway, it isn't a single act of a darker skin person mating with a lighter skin person that changes the allele frequencies in the population (it may or may not, but this would fall under the category of genetic drift, since the children's actual inheritance of lighter or darker skin isn't going to be 50-50, although it may on average be so). It is the tendency for lighter skinned people to be preferred as mating partners by the breeding population generally, or the tendency of the children of lighter skinned people to survive to adulthood and reproduce.

I don't think we are actually disagreeing, I'm probably just not understanding exactly what you are objecting to.

Well, of course a tendency of the children of lighter skinned people to survive to adulthood and reproduce will result in evolution toward lighter skin -- that's natural selection. Sexual selection works too; what I objected to was rousseau's statement of how it works. He wrote "People tended to breed with others who were more white, and less so with people who were darker." That's not how sexual selection works. For it to work that way would be mathematically impossible. Lighter skinned people being preferred as mating partners by the breeding population does not cause people to tend to breed more with others who are more white.

Suppose darker skinned men preferred lighter skinned women, and that caused those men to make more babies with lighter skinned women and fewer babies with darker skinned women. Well, that's just the sum of a whole lot of acts of a darker skinned man mating with a lighter skinned woman. Now look at that same sum of acts from the point of view of the women: from their point of view that's a whole lot of light-skinned women making babies with men darker than themselves. The postulated tendency of the men to breed with others who are more white must necessarily be matched by an equal and opposite tendency of the women to breed with others who are less white. (And of course the opposite scenario leads to the same conclusion -- if darker skinned women preferred lighter skinned men and that caused those women to make more babies with lighter skinned men and fewer babies with darker skinned men, then that tendency would be canceled out by lighter skinned men making more babies with darker skinned women. ) The overall tendency, considering both men and women, can only be exactly neutral.

So if preferring lighter skin doesn't lead to breeding more with people with lighter skin, how exactly does sexual selection work? Well, there are two mechanisms. (1) It can select specifically for sex-linked characteristics. Peahens' preference for showy tail feathers causes a tendency for more breeding with peacocks with showy tail feathers, and an equal and opposite tendency for peacocks to breed more with peahens with more drab tail feathers. The trait being selected for only shows up in one sex. This happens a lot in birds; but clearly it's not what's going on with human skin color. (2) When there's a preference for some trait in sex partners, animals compete for partners with that trait. The winners get their preference; the losers don't. Winning a competition typically correlates with overall health and vigor. So there's an inherited tendency for the offspring of those who didn't get their first choice to be weaker and sicker, and therefore less likely to reach reproductive age. It's sexual selection through natural selection.

 

[rousseau]

Suppose darker skinned men preferred lighter skinned women, and that caused those men to make more babies with lighter skinned women and fewer babies with darker skinned women. Well, that's just the sum of a whole lot of acts of a darker skinned man mating with a lighter skinned woman. Now look at that same sum of acts from the point of view of the women: from their point of view that's a whole lot of light-skinned women making babies with men darker than themselves. The postulated tendency of the men to breed with others who are more white must necessarily be matched by an equal and opposite tendency of the women to breed with others who are less white. (And of course the opposite scenario leads to the same conclusion -- if darker skinned women preferred lighter skinned men and that caused those women to make more babies with lighter skinned men and fewer babies with darker skinned men, then that tendency would be canceled out by lighter skinned men making more babies with darker skinned women. ) The overall tendency, considering both men and women, can only be exactly neutral.

You've got your math wrong here.

Say there is 100 people on a perfect continuum between completely black, and completely white. Each person has a set of alleles corresponding with their skin color. The darkest person has 100 black alleles, the middle people have 50 white and 50 black, and the whitest person has 100 white alleles. You're working under the assumption that reproduction is evenly distributed. But let's say 80 of those people reproduce and there is a slight bias toward lighter skin. If 45 on the whiter half manage to reproduce, and only 35 on the darker half reproduce, the next generation will have a different distribution of alleles that is skewed toward white, and as long as the prejudice is there this should continue until there is a new equilibrium (which is, for the most part, what we see in Brazil today).

Of course this isn't independent of other factors like a literal ability of black people to survive and reproduce. In Brazil's case there likely wasn't anything working in dark people's favour.

 

[Bomb#20]

If 45 on the whiter half manage to reproduce, and only 35 on the darker half reproduce, the next generation will have a different distribution of alleles that is skewed toward white, and as long as the prejudice is there this should continue until there is a new equilibrium (which is, for the most part, what we see in Brazil today).

Of course this isn't independent of other factors like a literal ability of black people to survive and reproduce. In Brazil's case there likely wasn't anything working in dark people's favour.

But that's just white people reproducing more. If you intend that to be a different factor from the literal ability of black people to survive and reproduce, then it sounds like you're saying the darker half simply choose to have fewer babies because of prejudice. I'm not seeing what that has to do with whom anyone breeds with.

Maybe we're talking at cross purposes. Can you give me an example of what you have in mind? Let's say there's a community with a population of 8. There are four women named W, X, Y and Z, and four men named w, x, y and z. The skin reflectivities of W and w are 25%, X and x are 28%, Y and y are 31%, and Z and z are 34%. Give me a possible list of pair-ups and how many babies each pair produces, where you'd describe the outcome as "People tended to breed with others who were more white, and less so with people who were darker."

 

[rousseau]

But that's just white people reproducing more.

Yes, a factor in white people reproducing more is that the people who reproduce are choosing lighter partners, not darker ones, therefore darker people are left out of future distributions. It's not just because black people are worse at reproducing, one of the reasons they're worse at reproducing is because there is a bias against mating with those of darker colors. So people with very dark tones are left out of the gene pool more often than people with lighter tones.

And the prejudice doesn't even have to come from partnering itself, it could also be due to prejudice in the workplace / economics etc.

 

[Toni]

But that's just white people reproducing more.

Yes, a factor in white people reproducing more is that the people who reproduce are choosing lighter partners, not darker ones, therefore darker people are left out of future distributions. It's not just because black people are worse at reproducing, one of the reasons they're worse at reproducing is because there is a bias against mating with those of darker colors. So people with very dark tones are left out of the gene pool more often than people with lighter tones.

And the prejudice doesn't even have to come from partnering itself, it could also be due to prejudice in the workplace / economics etc.

It's interesting to read these comments. I grew up surrounded by bigots who swore that blacks were constantly having as many babies as possible to get the most out of welfare. I think I've read similar suggestions here.

Now I'm reading that blacks are less competent at reproduction than are white people.

It's a little hard to reconcile. It seems there is a greater diversity of thought than I imagined. Also an apparent lack of interest in doing a quick google search of fertility rates in Europe, North America and....African nations.

 

[rousseau]

But that's just white people reproducing more.

Yes, a factor in white people reproducing more is that the people who reproduce are choosing lighter partners, not darker ones, therefore darker people are left out of future distributions. It's not just because black people are worse at reproducing, one of the reasons they're worse at reproducing is because there is a bias against mating with those of darker colors. So people with very dark tones are left out of the gene pool more often than people with lighter tones.

And the prejudice doesn't even have to come from partnering itself, it could also be due to prejudice in the workplace / economics etc.

It's interesting to read these comments. I grew up surrounded by bigots who swore that blacks were constantly having as many babies as possible to get the most out of welfare. I think I've read similar suggestions here.

Now I'm reading that blacks are less competent at reproduction than are white people.

It's a little hard to reconcile. It seems there is a greater diversity of thought than I imagined. Also an apparent lack of interest in doing a quick google search of fertility rates in Europe, North America and....African nations.

Africa and North America don't quite make a perfect analogy with Brazil, different policies, history, and cultural mix. At one point it had Natives, Africans, and Europeans at nearly equivalent numbers, without any type of racial segregation as seen in North America. And the diversity never existed in Africa which is an entirely different animal. And it's not just about ability to reproduce but genetic drift based on a number of factors.

So Brazil is really a unique case in the world with no perfect analogy.

I did some quick searching though because I don't really know much about this part of Brazil's history and these two articles were interesting:

Racial Whitening

Turns out at the turn of the 19th century there were both deliberate policies (limiting immigration to blacks, and promoting immigration of Europeans), as well as theories on how to 'breed' a whiter population. Couldn't find out if or how this was actually put into practice.

Race and Ethnicity in Brazil

By the sounds of this article there was a lot of miscegenation, which was less how I described, more a random mixing of colours that led to more neutrally coloured people. And in some cases it actually led to a polarization of colours.

Couldn't really find much substantive on Google Scholar, but did find a paper that described that 'colour' in addition to 'race' was a dominant theme. In other words, the shade you were made a real difference.

And that is my sort of researched post now that I'm not typing my posts quickly at work .

 

[Bomb#20]

Yes, a factor in white people reproducing more is that the people who reproduce are choosing lighter partners, not darker ones, therefore darker people are left out of future distributions. It's not just because black people are worse at reproducing, one of the reasons they're worse at reproducing is because there is a bias against mating with those of darker colors. So people with very dark tones are left out of the gene pool more often than people with lighter tones.

And the prejudice doesn't even have to come from partnering itself, it could also be due to prejudice in the workplace / economics etc.

It's interesting to read these comments. I grew up surrounded by bigots who swore that blacks were constantly having as many babies as possible to get the most out of welfare. I think I've read similar suggestions here.

Now I'm reading that blacks are less competent at reproduction than are white people.

No you aren't. Where did rousseau say anything about competence? Postulating equal competence at reproduction, blacks were likely to perform worse at it than whites on average because they typically faced greater external obstacles to reproduction.

It's a little hard to reconcile. It seems there is a greater diversity of thought than I imagined. Also an apparent lack of interest in doing a quick google search of fertility rates in Europe, North America and....African nations.

Rousseau and I were discussing the history of late 19th-century and early 20th-century Brazil. No doubt a quick google search of fertility rates in Europe, North America and African nations will tell us why the Brazilian population got whiter during that period. The apparent lack of interest here is your apparent lack of interest in reading for content rather than your personal triggers. Speaking of which...

The legal rape is long over.

Crime is not over.



The genetic diversity is more about protection from disease and recessive defects.

Nobody wants to be raped. But nobody living today is legally raping anyone.

The diversity would occur without the rape. The rape is not necessary. But the rape is long over.

At least we can revel in the sound knowledge that genetic exchange between groups never happens unless rape is involved and that therefore rape is a good thing.

Doesn't follow from anything I'm saying.

I'm talking about what did happen, not what should have happened.

What should have happened though leaves Africans in Africa and the millions of descendants of slaves living in the US never exist.

You make many assumptions, including that the presence of genetic markers identified as ‘european’ could only have found their way to to the genome of African Americans through the rape of African slaves and their decendants through the rape of slave women by white men of European descent.

No, untermensche assumed nothing of the sort. You are "reading between the lines", and poorly. You are shoehorning your own hangups and bugbears into his thoughts.

Further, your postulation that these rapes increased ‘genetic diversity’—presumably only for African Americans as you seem to ignore that any whites women might have had children by black men,

Your presumptions are on you. He did nothing to invite them.

is based upon the assumption that there is significant genetic differences between European and African populations compared with variations between individuals within African populations and within European populations.

People don't have to assume any random X you make up just because you've made some arbitrary mental association between X and whatever they're talking about. Untermensche's comments were silent and neutral on the relative magnitude of between-population vs. within-population differences. Stop projecting.

You seem to ignore millennia of human migration and cultural exchange along with the inevitable exchange of genes. Frankly it sounds as though you are making the argument that white slave owners raping their black slaves improved the stock by increasing their genetic diversity.

All in all I find your line of thinking flawed and disgusting.

Oh for the love of god. He's arguing against isolationism and anti-race-mixing bigotry. You're the one displaying flawed thinking. You're imputing bad motivations where there's no reason to, because you're conflating what untermensche said with what some completely different person in your past experience said -- the same thing you were doing to rousseau. Stop thinking that way. Read for content, not your pet triggers. I've rarely seen a poster here treat another as unfairly as you treated untermensche.

 

[Toni]

No you aren't. Where did rousseau say anything about competence? Postulating equal competence at reproduction, blacks were likely to perform worse at it than whites on average because they typically faced greater external obstacles to reproduction.

It's a little hard to reconcile. It seems there is a greater diversity of thought than I imagined. Also an apparent lack of interest in doing a quick google search of fertility rates in Europe, North America and....African nations.

Rousseau and I were discussing the history of late 19th-century and early 20th-century Brazil. No doubt a quick google search of fertility rates in Europe, North America and African nations will tell us why the Brazilian population got whiter during that period. The apparent lack of interest here is your apparent lack of interest in reading for content rather than your personal triggers. Speaking of which...

The legal rape is long over.

Crime is not over.



The genetic diversity is more about protection from disease and recessive defects.

Nobody wants to be raped. But nobody living today is legally raping anyone.

The diversity would occur without the rape. The rape is not necessary. But the rape is long over.

At least we can revel in the sound knowledge that genetic exchange between groups never happens unless rape is involved and that therefore rape is a good thing.

Doesn't follow from anything I'm saying.

I'm talking about what did happen, not what should have happened.

What should have happened though leaves Africans in Africa and the millions of descendants of slaves living in the US never exist.

You make many assumptions, including that the presence of genetic markers identified as ‘european’ could only have found their way to to the genome of African Americans through the rape of African slaves and their decendants through the rape of slave women by white men of European descent.

No, untermensche assumed nothing of the sort. You are "reading between the lines", and poorly. You are shoehorning your own hangups and bugbears into his thoughts.

Further, your postulation that these rapes increased ‘genetic diversity’—presumably only for African Americans as you seem to ignore that any whites women might have had children by black men,

Your presumptions are on you. He did nothing to invite them.

is based upon the assumption that there is significant genetic differences between European and African populations compared with variations between individuals within African populations and within European populations.

People don't have to assume any random X you make up just because you've made some arbitrary mental association between X and whatever they're talking about. Untermensche's comments were silent and neutral on the relative magnitude of between-population vs. within-population differences. Stop projecting.

You seem to ignore millennia of human migration and cultural exchange along with the inevitable exchange of genes. Frankly it sounds as though you are making the argument that white slave owners raping their black slaves improved the stock by increasing their genetic diversity.

All in all I find your line of thinking flawed and disgusting.

Oh for the love of god. He's arguing against isolationism and anti-race-mixing bigotry. You're the one displaying flawed thinking. You're imputing bad motivations where there's no reason to, because you're conflating what untermensche said with what some completely different person in your past experience said -- the same thing you were doing to rousseau. Stop thinking that way. Read for content, not your pet triggers. I've rarely seen a poster here treat another as unfairly as you treated untermensche.

wow

 

[untermensche]

The legal rape is long over.

Crime is not over.

The genetic diversity is more about protection from disease and recessive defects.

Nobody wants to be raped. But nobody living today is legally raping anyone.

The diversity would occur without the rape. The rape is not necessary. But the rape is long over.

At least we can revel in the sound knowledge that genetic exchange between groups never happens unless rape is involved and that therefore rape is a good thing.

Doesn't follow from anything I'm saying.

I'm talking about what did happen, not what should have happened.

What should have happened though leaves Africans in Africa and the millions of descendants of slaves living in the US never exist.

You make many assumptions, including that the presence of genetic markers identified as ‘european’ could only have found their way to to the genome of African Americans through the rape of African slaves and their decendants through the rape of slave women by white men of European descent.

It was legal to rape your slave.

I suspect it happened.

I never witnessed it.

This fails to take into consideration any intermarriage between Africans and Europeans prior to the institution of slavery in what became the US, the mutual and consensual relationships between black and white Americans post slavery and whether these markers are really unique only to defined geographic areas.

What fails to take this into consideration?

Which comment? I specifically say that diversity can take place without rape.

Further, your postulation that these rapes increased ‘genetic diversity’—presumably only for African Americans as you seem to ignore that any whites women might have had children by black men, is based upon the assumption that there is significant genetic differences between European and African populations compared with variations between individuals within African populations and within European populations. You seem to ignore millennia of human migration and cultural exchange along with the inevitable exchange of genes. Frankly it sounds as though you are making the argument that white slave owners raping their black slaves improved the stock by increasing their genetic diversity.

The rapes did increase genetic diversity.

That is not disputed by anyone.

All in all I find your line of thinking flawed and disgusting.

Which specific words?

 

[lpetrich]

DNA Study from 23andMe Traces Violent History of American Slavery - The New York Times
noting
Genetic Consequences of the Transatlantic Slave Trade in the Americas: The American Journal of Human Genetics
Slave Voyages

Back to the NYT:

The report, which included more than 50,000 people, 30,000 of them with African ancestry, agrees with the historical record about where people were taken from in Africa, and where they were enslaved in the Americas. But it also found some surprises.

For example, the DNA of participants from the United States showed a significant amount of Nigerian ancestry — far more than expected based on the historical records of ships carrying enslaved people directly to the United States from Nigeria.

...
After consulting another historian, the researchers learned that enslaved people were sent from Nigeria to the British Caribbean, and then were further traded into the United States, which could explain the genetic findings, he said.

The study illuminates one of the darkest chapters of world history, in which 12.5 million people were forcibly taken from their homelands in tens of thousands of European ships. It also shows that the historical and genetic records together tell a more layered and intimate story than either could alone.

Of the 12.5 million people who were sent across the Atlantic, 5.7 million came from West Central Africa.

The African ancestry of Latin Americans is usually from two or three regions in Africa, mostly WCA, Senegambia, and the Bight of Benin.

But African ancestry in the US and the British Caribbean is from six regions in Africa.

The historical record shows that of the 10.7 million enslaved people who disembarked in the Americas (after nearly 2 million others died on the journey), more than 60 percent were men. But the genetic record shows that it was mostly enslaved women who contributed to the present-day gene pool.

The asymmetry in the experience of enslaved men and women — and indeed, many groups of men and women in centuries past — is well understood. Enslaved men often died before they had a chance to have children. Enslaved women were often raped and forced to have children.

...
The scientists calculated that enslaved women in the United States contributed 1.5 times more to the modern-day gene pool of people of African descent than enslaved men. In the Latin Caribbean, they contributed 13 times more. In Northern South America, they contributed 17 times more.

What’s more, in the United States, European men contributed three times more to the modern-day gene pool of people of African descent than European women did. In the British Caribbean, they contributed 25 times more.

This was a result of regional variations of enslaved men getting to reproduce -- much more in the US than in Latin America. Malaria was common in the latter region, along with dangerous practices like rice farming. Also common in Latin America was inviting in European male settlers to interbreed with black women.

It is interesting that US blacks should have a sizable white female genetic contribution. This is most likely post-slavery, and it also suggests that a similar part of their white male genetic contribution is also post-slavery. Meaning that it wasn't all horny masters like Thomas Jefferson and James Henry Hammond.