Race debate (continued)

That said, how would ‘race’ need to be defined for the statement “it’s much harder to find a marrow match outside ones race” to be true?

To respond to the closed GQ thread, my white father successfully received and used the liver of a black female donor. QED.

In the U.S. you can treat the statement as “true,” now, based on the social construct of race that we use, here. Those groups that we identify as “racial” have the greatest percentage of intra-group marriage. (Note, on the site that listed the ethnic categories, that one category is “Hispanic” which does not have a racial component.)

I suspect that if we went to Africa and looked for donor matches across the entire continent, we would need to spend more effort simply because there is greater genetic diversity, there. While there is a certain bottleneck/founder effect among people identified as black in the U.S., based on the tendency to take slaves from the same regions, there is no such narrowing of genetic differentiation on the African continent. Similarly, the numbers of Asian people who have immigrated to the U.S. have tended (until recently) to come from a fairly small number of regions in Asia and have tended toward intramarriage, as well.

I was having a discussion about organ transplants with a doctor friend of mine the other day. I’m sure there are those on this board who could explain it in detail, but my doctor friend outlined how the “blood group” scheme reported in the press is pretty much an oversimplification. I’d guess this is true for marrow transplants as well.

As for a genetic basis for race, the state of the art at this point is pretty much a statistical issue. Geneticists can pinpoint markers that suggest a high probability that the subject is of a certain race, but that’s about as good as it gets. And even then, it’s really more an issue of pinpointing a certain geographical region, and then, by inference, figuring out race. But, as Tom said above, this gets complicated in the US due to the high degree of racial mixing.

There’s a new book out that sheds some very interesting light on this subject: The Journey of Man by Spence Wells. There was a PBS special based on this book a month or so ago, and I was very disapointed with that show. It was extremely superficial. I picked up the book the other day, and found it to be a whole lot better.


The state of the art in genetics and race would be The Human Genome Diversity Project and they are not looking for distinctive “race markers” because there aren’t any.

So then how would you define race as it applies here? Along what lines are these groups split that there is also a correlation in bone marrow?

What are you identifying as a “correlation in bone marrow”?

When matching tissue types, we have a higher probability of finding people with closer matches from among people who have common descent. My initial comment in the GQ thread was

There is no one-to-one correspondence. You cannot pick an African off the street in Nairobi and expect to get a good tissue match with another citizen of Nairobi. You cannot pick a European off the street in Warsaw and expect to get a good tissue match with another citizen of Warsaw. What you do find is that if you have a citizen of Nairobi who needs a transplant, perhaps (and I am making up the numbers here) 1 person in a thousand from Nairobi will give a good match while 3 persons in 10,000 from Warsaw or Beijing or Djakarta will give a good match. (But there will be people from Warsaw, Beijing, and Djakarta who will provide a good match to a person from Nairobi–they will simply be harder to find.)

Therefore, in the U.S., where we have a large population brought from all over the world, the fact that European-descended peoples are both much more populous and (currently) much more likely to agree to organ donations means that the peoples in the other smaller and less-likely-to-donate populations have greater difficulty in finding matches when they need them.

In order to recruit more donors for the people who have a harder time finding donations, the people seeking donors have begun outreach programs to the ethnic groups who do not currently donate as frequently. Social shorthand uses the word race to identify the Africans, Asians, Indians, and Oceanic peoples–and winds up throwing in the Hispanic group, as well.

Here is the Donor Alliance link from the previous thread. (Adobe Acrobat needed.)
And here is the “recruitment” page from National Marrow Donor Program (NMDP).

"The state of the art in genetics and race would be The Human Genome Diversity Project and they are not looking for distinctive “race markers” because there aren’t any. "


The HGD Project will also provide the scientific data to confirm and support what is already clear from populations studies – that, in biological terms, there is no such thing as a clearly defined race. Biologically, there is a continual graduation from one population to another: populations are defined on a statistical basis rather than on the basis that each has entirely distinct and different genetic or physical characteristics. Most importantly, therefore, the results of the Project are expected to undermine the popular belief that there are clearly defined races, to contribute to the elimination of racism and to make a major contribution to the understanding of the nature of differences between individuals and between human populations.

PC science. Just what we need. Why do these guys even bother with their research since they have stated they already know the answer?

I’ll stick with more independent researchers who don’t have a political ax to grind, thanks.

It’s called a hypothesis. Perhaps it is even beyond the level of hypothesis into theory, as it is already well supported by evidence. Just like someone researching early hominids would tell you that australopithicine fossils support evolution.

The HGD is much more important than just looking at race. It is all part of establishing well known polymorphisms which can be used in the future for mapping disease loci more easily.

About bone marrow matching. While blood group is certainly part of it, you can basically think of blood groups as only one set of many proteins on the surface of a blood cell. Other proteins are much more important in determining the normal immune response based on individual – this is called the MHC (Major Histocompatibility Complex), which encodes the HLA (Human Leukocyte Antigen) proteins on chromosome 6. Basically, there are many different alleles of individual HLA genes, although they are tightly linked – different alleles tend to stay together – which we call a haplotype. Since there are two copies of every gene, you have to get a haplotype match on each chromosome. So there is slightly better than a 1 in 4 chance that you share an HLA match with a sibling, and far less with any other relative (as you get one from you dad and one from your mom). The effort to form a bone marrow donor library involves quick HLA typing of each donor.

Haplotypes, in terms of population genetics, are very interesting. I can get into a broad discussion if you so wish. But let me say that there are no private haplotypes for any race (as tomndebb stated above). Yes, there is a variation in the distribution of haplotypes between different subgroups of humanity which is broadly related to ancient migrations. But these usually do not resemble races (i.e. Paleolithic versus Neolithic Europeans and Asians). Even when they do, we are only talking about a variation in distributions, not absolute differences. So it is all a matter of degree. In science, we have a hard time finding uses for differences that are “only a matter of degree” – we look for hard, reproducible lines we can draw in order to define scientifically useful groups. Since “race” fails as this, we don’t use it.

“the results of the Project are expected… to contribute to the elimination of racism”

Yes, it’s beyond a hypothesis alright. It’s called a politcal agenda.

Anyway, I don’t think we disagree on the basic science, if you read my original post. I just think that politics makes for lousy science.

I’m identifying it as the greater likelihood of a bone marrow match from one’s race, whatever ‘race’ means.

The statement from the GQ thread said that it is much harder to find a marrow match outside one’s race. Given that the concept of race has become quite subjective, what objective, descriptive phrase could you substitute for the word ‘race’ to make that statement medically relevant?

The NMDP site says “Because HLA tissue types are inherited, patients are more likely to find a matched donor from their own racial or ethnic group.” Again, how must ‘racial’ be defined for that statement to be correct, considering that it has been argued that race, as traditionally defined, is not a biological construct?

It is true, now, provided one realizes that the word is being used in a sociological way, not a purely biological way. Where will one find markers more frequently similar to one’s own? Among the “racial or ethnic” group that has been intramarrying for the longest time.

The NMDP statement refers to inherited tissue types, which implies that their definition of race has a significant biological component, as opposed to traditional definitions of race (i.e., black and white) that span ethnic groups and intermarriage to the point where there is no longer a detectable genetic distinction. Here I am, a white Jewish guy who’s grandparents came from Russia and Austria. With whom does the NMDP think I’d have the most likely marrow compatibility? Jews? Russians? Whites? zwaldds? What is my ‘race’ in this context?

The reason why the result of the project are expected to contribute to the elimination of racism is because all research and evidence so far shows that the definition of race used today is incorrect. This quote of yours, John Mace

is incorrect. Genetists have not found markers that suggest a high probability of which race the subject belongs to. What geneticist have been finding over and over and over and over and over again is that race is an invalid scientific concept.

As for the PCness of mapping human gene diversity-- the strongest opposition this project (which, by the way, will be mapping the differences in the human genome --if anyone is going to find these genetic race markers it’s going to be them) is from minority groups themselves.

In order: zwaldds, Russian-Jews, whites.
This would be based on most likely kinship. (I merged Russians and Jews, because that is where the kinship would lie. I have no idea (without seeing your genealogy) whether you would have more kinship with a (Russian) Georgian Cossack or a (Jewish) Israeli Mizrahi.)

Note, that the NMDP is using “racial and ethnic” as broad categories of people who do not currently donate organs or marrow. They are not identifying specific people to segregate by group, they are, instead, looking to broaden the base of the population so as to get wider diversity (and more frequent matches) among all the groups. There is no special outreach program to whites, because they are responding fairly well to the general encouragement to register and donate.

‘zwaldds’ I understand…family. I can see why I’d have a better chance of finding compatible marrow from my family than from other families. How does ‘whites’ fit in? I’d have a better chance of finding compatible marrow among whites than…what?

I think that this refers to the ability to make a statistical link between the probability of frequency of certein genetic markers and geographic origin.

The was an article in Science magazine (requires registration and Acrobat, fifth article below NEW THIS WEEK:) last December 20: King and Motulsky, HUMAN GENETICS: Mapping Human History, Science 2002 298: 2342-2343. (King and Motulsky authored the article, the study was conducted by Noah A. Rosenberg, Jonathan K. Pritchard, James L. Weber, Howard M. Cann, Kenneth K. Kidd, Lev A. Zhivotovsky, and Marcus W. Feldman.)

In it, they described using “genotypes at 377 autosomal microsatellite loci in 1056 individuals from 52 populations” to identify origins of different people from different populations. Under statistical analysis, they discovered that at a certain level of grouping, they could identify the origins of an individual as being from one of several geographic regions: “Africa, Europe, the Middle East, Central/South Asia, East Asia, Oceania, and America.” Among these, Africa, East Asia, Oceania, and America can be thought of as associated with the Negroid, Mongoloid, Malay, and American Indian groups posited by Blumenbach in the eighteenth century. The three remaining regions, however, share populations generally considered either Caucasian or Mongoloid.
Associating the geographic groupings with the word race ignores that within the geographic regions are distinct populations, as well. So, while two separate combinations of clusters may each point to African or Central/South Asia as a point of origin, they do not indicate that the clusters within Africa or Central/South Asia are related. (This does not hold strictly true in Europe, where the enormous numbers of migrations and invasions have turned them (us) into real mutts.)

One aspect of the study that bears noting is that nearly all populations (with exceptions only among isolated groups) shared all the loci. In order to establish the geographic region, they had to do statistical probability studies on the prevalence of the loci associations among the various groups with multiple computer runs against the data in various configurations (and no guarantee that any individual would have all the loci under analysis, as long as they had sufficient groupings of most of those loci).

They close with the following statement:

I would tend to re-word the quoted text, above, as
“Geneticists can find stastitical relationships that suggest a high probability that the subject is of a certain geographic region, but that’s about as good as it gets.”

The rest of the U.S. population. Just as you would have a better chance of finding straight brown or blonde hair or blue eyes among the white population.

OK, so then returning to the NMDP statement “patients are more likely to find a matched donor from their own racial or ethnic group”, my racial group could be defined as something as general as ‘white’ and that statement would still be true (correct me if I’m wrong). Biggirl made the comment that ‘race is an invalid scientific concept’, which is what I’ve read previously in race threads. If, as a white person, I have a better chance of finding compatible marrow from white donors than non-white donors, then by what definition is race scientifically invalid?

Biggirl: You convenient left off an important part of my original post:

“As for a genetic basis for race, the state of the art at this point is pretty much a statistical issue. Geneticists can pinpoint markers that suggest a high probability that the subject is of a certain race, but that’s about as good as it gets. And even then, it’s really more an issue of pinpointing a certain geographical region, and then, by inference, figuring out race.”

Pls note the last sentence. Yes, the “race” is inferred by pinpointing geographic origin. If I say I have pinpointed someone’s geographic origin as Central Europe, I would, to a high degree of statistical significance, infer that the person is Caucasian.