Understanding through Discussion


Welcome! You are not logged in. [ Login ]
EvC Forum active members: 78 (8905 total)
Current session began: 
Page Loaded: 04-22-2019 8:35 PM
23 online now:
DrJones*, JonF, Percy (Admin), Tanypteryx, Theodoric (5 members, 18 visitors)
Chatting now:  Chat room empty
Newest Member: WookieeB
Post Volume:
Total: 850,099 Year: 5,136/19,786 Month: 1,258/873 Week: 154/460 Day: 96/58 Hour: 1/7


Thread  Details

Email This Thread
Newer Topic | Older Topic
  
Prev123
4
56
...
19NextFF
Author Topic:   Human Races
DBlevins
Member (Idle past 1884 days)
Posts: 652
From: Puyallup, WA.
Joined: 02-04-2003


Message 46 of 274 (63263)
10-29-2003 4:53 AM
Reply to: Message 43 by Speel-yi
10-28-2003 11:59 AM


Says who?

www.cartage.org.lb

"Unlike the typological and populational models, the clinal model does not result in the definition of distinct groups or races of people."

www.yale.edu/yjhple/volume_1/pdf/033%20(koenig).pdf

YALE JOURNAL OF HEALTH POLICY, LAW, AND ETHICS
The Meanings of “Race” in the New Genomics:
Implications for Health Disparities Research
Sandra Soo-Jin Lee, Ph.D.,* Joanna Mountain, Ph.D.,† and Barbara A.
Koenig, Ph.D.‡, (2001)

"In this paper we provide a strong critique of the continued use of race as a legitimate scientific variable. We offer an historical analysis of how the concept of race has changed in the United States and discuss the reification of race in health research. We discuss how genetic technology has been deployed in “proving” racial identity, and describe the consequences of locating human identity in the genes. The implications of the continued use of race in the new genomic medicine—in particular the creation of racialized diseases—is highlighted. We warn about the consequences of a shift toward population-based care, including targeted genetic screening for racially identified “at-risk” groups, including the potential for stigmatization and discrimination. A less commonly identified hazard is the epistemological turn towards genetic reductionism. We suggest that the application of a näive genetic determinism will not only
reinforce the idea that discrete human races exist, but will divert attention from the complex environmental, behavioral, and social factors contributing to an excess burden of illness among certain segments of the diverse U.S. population. The intersection of the genomics revolution with the health disparities initiative should serve as a catalyst to a long overdue public policy debate about the appropriate use of the race concept in biomedical research and clinical practice."

"The widely accepted consensus among evolutionary biologists and
genetic anthropologists is that biologically identifiable human races do not exist; Homo sapiens constitute a single species, and have been so since their evolution in Africa and throughout their migration around the world.18 Population genetics provides the best evidence for this conclusion: The genetic variation within a socially recognized human population is greater than the genetic variation between population groups."

Given that assumption, you can't tell blue from red on a spectrum since colors are distributed clinally. You can visually tell red from orange easily, but you probably would be hard pressed to tell exactly where one began and another ended. By your reasoning, we can't tell blue from red and this is a ridiculous proposition.

Ahh, but we aren't talking about seperating colors now are we? While clinal models show that there is some genetic differences coresponding with geography, it is usually discontinuous. Never mind the fact that human populations have been migrating for ages. Look at a clinal map! Are you suggesting that those areas of high incidence for B blood allele correspond with a "race"? Or hemoglobin S clinal distributions correspond with a "race"? You realize that many of these groups overlap? Of what use is the use of a clinal model distiniction for "race" if they overlap? The best that can be said is that there is the possibility of regional genetic differences when diagnosing a medical condition but you'd have to be careful in classification because of the amount of discontinuities.

Take a look at the skyrocketing rates of diabetes among many indigenous people and the rates of hypertension among African-Americans. Mismatching the environment to the people is a lethal combination for many minorities.

If it were only so simple as to assume that ALL African-Americans had high rates of hypertension or that ALL indigenous populations (by the way I am assuming you are talking about Native Americans and not all indigenous populations) have skyrocketing rates of diabetes. What is the cause for these problems? Genetic? Possibly but certainly not for ALL. Is hypertension just an effect relating to their environment in the U.S? Racial biases that lead to increased poverty risk would make a lot of people hypertensive. Is there a genetic disposition for diabetes among Native Americans or just a penchant for Mountain Dew? I'd be surprised if there isn't a skyrocketing rate for diabetes among MOST americans regardless of ethnicity.

fixed url to keep page from becoming too wide - The Queen

[This message has been edited by AdminAsgara, 10-29-2003]


This message is a reply to:
 Message 43 by Speel-yi, posted 10-28-2003 11:59 AM Speel-yi has not yet responded

  
Peter
Member (Idle past 2031 days)
Posts: 2160
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 47 of 274 (63280)
10-29-2003 7:22 AM
Reply to: Message 16 by NosyNed
10-19-2003 2:42 AM


quote:

In that time the gentic differences between races is still smaller than that within a given "race".

I've heard this a lot -- are there figures/quantitative reports
on this that you know of/can quote?

Not disputing it, just want to look over the data.


This message is a reply to:
 Message 16 by NosyNed, posted 10-19-2003 2:42 AM NosyNed has responded

Replies to this message:
 Message 48 by NosyNed, posted 10-29-2003 10:22 AM Peter has responded
 Message 52 by DBlevins, posted 10-29-2003 7:51 PM Peter has acknowledged this reply

    
NosyNed
Member
Posts: 8842
From: Canada
Joined: 04-04-2003
Member Rating: 7.4


Message 48 of 274 (63301)
10-29-2003 10:22 AM
Reply to: Message 47 by Peter
10-29-2003 7:22 AM


Good point, I keep reading it as a snippet here and there but haven't seen anything backing it up. I'll try to find a source for you. I suppose I'm falling for it because it seems credible but there may in fact be several ways to measure this.

This isn't it but is a useful addition to the discussion here:
http://www.physanth.org/positions/race.html

I think it is emphasizing the lack of usefulness of 'race'.

Here is the statement repeated:
from: http://www.washington.edu/burkemuseum/kman/the_idea_of_race.htm
"Human populations are not unambiguous, clearly demarcated, biologically distinct groups. Evidence from the analysis of genetics (e.g., DNA) indicates that there is greater variation within racial groups than between them. These facts render any attempt to establish lines of division among biological populations both arbitrary and subjective."
American Anthropological Association, 1998

and from here: http://www.vsu.edu/isrr/aa_assoc.htm

"With the vast expansion of scientific knowledge in this century, however, it has become clear that human populations are not unambiguous, clearly demarcated, biologically distinct groups. Evidence from the analysis of genetics (e.g., DNA) indicates that most physical variation, about 94%, lies within so-called racial groups. Conventional geographic "racial" groupings differ from one another only in about 6% of their genes. This means that there is greater variation within "racial" groups than between them."

However, none of these are pointing to an original source. That is suspicious. It is politically correct to support this view and then to see it repeated so often without proper orginal sources is odd. Maybe I didn't search hard enough

There is a disucssion of issues where that seems to conclude that while race has some value it can't be over used either. There is a bit of correlation but that doesn't say anything about one individual
http://www.bioethics.upenn.edu/faculty/pubs/cho.pdf

[This message has been edited by NosyNed, 10-29-2003]

[This message has been edited by NosyNed, 10-29-2003]


This message is a reply to:
 Message 47 by Peter, posted 10-29-2003 7:22 AM Peter has responded

Replies to this message:
 Message 59 by Peter, posted 10-30-2003 4:44 AM NosyNed has not yet responded

  
Tsegamla
Inactive Member


Message 49 of 274 (63355)
10-29-2003 6:01 PM
Reply to: Message 36 by Rationalist
10-27-2003 2:12 AM


quote:
Yes, but human nature can't really be altered by choice to any great extent, so it doesnt' make any difference. The best we can hope for is to keep social and world economics in the "cooperatation" mode and keep it from slipping into a perception of "zero sum" as best we can. When it does slip into a zero sum condition, that's when all hell inevitably breaks loose.

A little off topic, but...
I'm reading Nonzero right now. Neat book. Are there any other books you know of that carry a similar viewpoint on "the arrow of human history?"


This message is a reply to:
 Message 36 by Rationalist, posted 10-27-2003 2:12 AM Rationalist has not yet responded

  
Loudmouth
Inactive Member


Message 50 of 274 (63356)
10-29-2003 6:10 PM
Reply to: Message 7 by crashfrog
10-18-2003 4:24 PM


As to the Halle Berry/Porman pics, just thought you should know that Halle's mom is white.
This message is a reply to:
 Message 7 by crashfrog, posted 10-18-2003 4:24 PM crashfrog has responded

Replies to this message:
 Message 51 by crashfrog, posted 10-29-2003 6:53 PM Loudmouth has responded

  
crashfrog
Inactive Member


Message 51 of 274 (63362)
10-29-2003 6:53 PM
Reply to: Message 50 by Loudmouth
10-29-2003 6:10 PM


As to the Halle Berry/Porman pics, just thought you should know that Halle's mom is white.

Sure, but we don't call her - nor does she call herself - a white actress, do we? Nor do we call her black-white, or half-black-half-white - she's black.

Why? Because our racial terms betray an inherent bias - you can't be white unless you're all white, but all it takes is a little black to be black. How could such a ridiculously inconsistent system have any scientifc validity? It's ridiculous to say that it reflects "ancestry", because every human being has two ancestries, from their two parents. Yet we only refer to one of them when we talk about race. Generally it's the ancestry often viewed as inferior, in times past- which is why Halle Berry is black and not white.


This message is a reply to:
 Message 50 by Loudmouth, posted 10-29-2003 6:10 PM Loudmouth has responded

Replies to this message:
 Message 62 by Loudmouth, posted 10-30-2003 12:10 PM crashfrog has not yet responded
 Message 71 by Peter, posted 11-04-2003 3:40 AM crashfrog has not yet responded
 Message 231 by Gaius Caligula, posted 03-05-2004 10:08 PM crashfrog has responded

  
DBlevins
Member (Idle past 1884 days)
Posts: 652
From: Puyallup, WA.
Joined: 02-04-2003


Message 52 of 274 (63373)
10-29-2003 7:51 PM
Reply to: Message 47 by Peter
10-29-2003 7:22 AM


Here is a snippet which points out a couple of figures.

This one is from Washington University:
Biological differences among races do not exist, WU research shows
http://record.wustl.edu/archive/1998/10-15-98/articles/races.html

"Templeton analyzed genetic data from mitochondrial DNA, a form inherited only from the maternal side; Y chromosome DNA, paternally inherited DNA; and nuclear DNA, inherited from both sexes. His results showed that 85 percent of genetic variation in the human DNA was due to individual variation. A mere 15 percent could be traced to what could be interpreted as "racial" differences.
"The 15 percent is well below the threshold that is used to recognize race in other species," Templeton said. "In many other large mammalian species, we see rates of differentiation two or three times that of humans before the lineages are even recognized as races. Humans are one of the most genetically homogenous species we know of. There's lots of genetic variation in humanity, but it's basically at the individual level. The between-population variation is very, very minor.""

ahh just thought I'd add this in as well

http://notes.utk.edu/bio

"Concludes Howard L. McLeod, a professor of medicine at the Washington University School of Medicine in Missouri, "There is no clear link between skin pigment and drug metabolism genes. Skin pigment is a lousy surrogate for drug metabolism status or most any aspect of human physiology."10"

10 H.L. McLeod, "Pharmacogenetics: more than skin deep," Nature Genetics, 29:247-8, November 2001.

[This message has been edited by DBlevins, 10-29-2003]

edited url to fix page width - The Queen

[This message has been edited by AdminAsgara, 10-29-2003]


This message is a reply to:
 Message 47 by Peter, posted 10-29-2003 7:22 AM Peter has acknowledged this reply

Replies to this message:
 Message 63 by Speel-yi, posted 10-31-2003 3:18 AM DBlevins has not yet responded

  
Tsegamla
Inactive Member


Message 53 of 274 (63382)
10-29-2003 9:10 PM


I agree that race is pretty insignificant today (or should be), but that doesn't mean we shouldn't study it. I'm sure others disagree, but I don't think that things should be ignored just because they aren't useful. Granted, a good deal of the science involved in race goes right over my head (as I'm new to all of this stuff), but I'm sure a decent amount of it is valid and true. If we have the means to investigate something, we might as well do it just for the sake of knowing more about it. English classes are pretty much useless, but a lot of people study the material just because they find it interesting. If certain results popped up that gave racists more ammunition, we shouldn't waste our time worrying about what they might say. We all know that you can teach a black man, white man, or any man how to build a rocket with the proper training. Let them get off on it if they want, but their bigotry shouldn't hinder studies of the subject.
Replies to this message:
 Message 54 by crashfrog, posted 10-29-2003 9:58 PM Tsegamla has responded

  
crashfrog
Inactive Member


Message 54 of 274 (63397)
10-29-2003 9:58 PM
Reply to: Message 53 by Tsegamla
10-29-2003 9:10 PM


I agree that race is pretty insignificant today (or should be), but that doesn't mean we shouldn't study it.

But what's to study?

It's like saying "the tooth fairy may be insignificant, but that doesn't mean we shouldn't study it." Ok, the tooth fairy doesn't exist, so what's to study?

Now, if you meant "cultural perceptions of race exist, so they should be studied," I agree. But race itself is a non-entity, so what's to study? Study the perceptions of race, yes. But you're wasting your time trying to study something that doesn't even exist.


This message is a reply to:
 Message 53 by Tsegamla, posted 10-29-2003 9:10 PM Tsegamla has responded

Replies to this message:
 Message 55 by Tsegamla, posted 10-29-2003 10:47 PM crashfrog has responded

  
Tsegamla
Inactive Member


Message 55 of 274 (63404)
10-29-2003 10:47 PM
Reply to: Message 54 by crashfrog
10-29-2003 9:58 PM


Well, a black guy is obviously different from a white guy. It's not an imaginary difference; they obviously have different skin colors. There has to be some sort of scientific explanation for that. So, whether it's only skin deep or if it goes further, we should still study various physical differences of different races. Race definitely exists to some degree. Asian, African, European, whatever. We should study any existing differences, no matter if it's a big deal or not.
This message is a reply to:
 Message 54 by crashfrog, posted 10-29-2003 9:58 PM crashfrog has responded

Replies to this message:
 Message 56 by Mammuthus, posted 10-30-2003 3:23 AM Tsegamla has not yet responded
 Message 61 by crashfrog, posted 10-30-2003 8:52 AM Tsegamla has not yet responded

  
Mammuthus
Member (Idle past 4583 days)
Posts: 3085
From: Munich, Germany
Joined: 08-09-2002


Message 56 of 274 (63425)
10-30-2003 3:23 AM
Reply to: Message 55 by Tsegamla
10-29-2003 10:47 PM


Hi T,

quote:
Well, a black guy is obviously different from a white guy. It's not an imaginary difference; they obviously have different skin colors. There has to be some sort of scientific explanation for that. So, whether it's only skin deep or if it goes further, we should still study various physical differences of different races.

If a trait varies in the population, it is amenable to genetic analysis and there is probably someone studying it. Pigmentation differences are important for medically related work such as skin cancer so the basis of trait variance among groups is under study.

quote:
Race definitely exists to some degree. Asian, African, European, whatever

However, race does not exist. There is more variation among Africans than between Africans and Europeans. So how can you look at a person and catagorize them as belonging to a race? And superficial characters like skin color are irrelevant. You can obtain a great dea of morphological difference without it having to rely on huge genetic differences for example morphotypes of artic char. Not to mention there has been gene flow among all of the different human groups blurring the lines even further.

quote:
We should study any existing differences, no matter if it's a big deal or not.

I agree. But race as a criteria is a hinderance. The existing differences have to be studied at the population level where ethnic differences (that can lead to isolation and hence show up in the genes) regional differences, environmental differences etc. can all be taken into account to give a more accurate result. That is why current human population studies are not just based on random sampling of a couple of "Asian" guys and europeans but are usually concerned with sampling multiple populations from different regions.

cheers,
M


This message is a reply to:
 Message 55 by Tsegamla, posted 10-29-2003 10:47 PM Tsegamla has not yet responded

Replies to this message:
 Message 57 by Minnemooseus, posted 10-30-2003 3:54 AM Mammuthus has responded

  
Minnemooseus
Member
Posts: 3709
From: Duluth, Minnesota, U.S. (West end of Lake Superior)
Joined: 11-11-2001
Member Rating: 7.8


Message 57 of 274 (63432)
10-30-2003 3:54 AM
Reply to: Message 56 by Mammuthus
10-30-2003 3:23 AM


quote:
There is more variation among Africans than between Africans and Europeans.

Care to elaborate on this? Are you saying that variations among Europeans are smaller than variations in Africans, and the field of European variations falls within the field of variations between Africans?

Moose


This message is a reply to:
 Message 56 by Mammuthus, posted 10-30-2003 3:23 AM Mammuthus has responded

Replies to this message:
 Message 58 by Mammuthus, posted 10-30-2003 4:39 AM Minnemooseus has not yet responded

    
Mammuthus
Member (Idle past 4583 days)
Posts: 3085
From: Munich, Germany
Joined: 08-09-2002


Message 58 of 274 (63434)
10-30-2003 4:39 AM
Reply to: Message 57 by Minnemooseus
10-30-2003 3:54 AM


Here are some references. Yes, Africa has the most diversity. According to the out of Africa hypothesis of human evolution, we originated in Africa, expanded and then migrated out to colonize the rest of the world. Though there must have been a great deal of migration in and out of Africa, the end effect is that colonized areas would show less genetic diversity than the original source population i.e. Africa should have more genetic variation among populations than say Europe for example

Genome Res. 2003 Jul;13(7):1607-18. Epub 2003 Jun 12. Related Articles, Links

Genetic variation among world populations: inferences from 100 Alu insertion polymorphisms.

Watkins WS, Rogers AR, Ostler CT, Wooding S, Bamshad MJ, Brassington AM, Carroll ML, Nguyen SV, Walker JA, Prasad BV, Reddy PG, Das PK, Batzer MA, Jorde LB.

Department of Human Genetics, University of Utah, Salt Lake City, Utah 84112, USA.

We examine the distribution and structure of human genetic diversity for 710 individuals representing 31 populations from Africa, East Asia, Europe, and India using 100 Alu insertion polymorphisms from all 22 autosomes. Alu diversity is highest in Africans (0.349) and lowest in Europeans (0.297). Alu insertion frequency is lowest in Africans (0.463) and higher in Indians (0.544), E. Asians (0.557), and Europeans (0.559). Large genetic distances are observed among African populations and between African and non-African populations. The root of a neighbor-joining network is located closest to the African populations. These findings are consistent with an African origin of modern humans and with a bottleneck effect in the human populations that left Africa to colonize the rest of the world. Genetic distances among all pairs of populations show a significant product-moment correlation with geographic distances (r = 0.69, P < 0.00001). F(ST), the proportion of genetic diversity attributable to population subdivision is 0.141 for Africans/E. Asians/Europeans, 0.047 for E. Asians/Indians/Europeans, and 0.090 for all 31 populations. Resampling analyses show that approximately 50 Alu polymorphisms are sufficient to obtain accurate and reliable genetic distance estimates. These analyses also demonstrate that markers with higher F(ST) values have greater resolving power and produce more consistent genetic distance estimates.

Here is one example of migration showing a measureable effect in the gene pool

Hum Biol. 2002 Oct;74(5):645-58. Related Articles, Links

Y-chromosome analysis in Egypt suggests a genetic regional continuity in Northeastern Africa.

Manni F, Leonardi P, Barakat A, Rouba H, Heyer E, Klintschar M, McElreavey K, Quintana-Murci L.

Laboratoire d'Anthropologie Biologique (CNRS FRE 2292); Musee de l'Homme MNHN, Paris, France.

The geographic location of Egypt, at the interface between North Africa, the Middle East, and southern Europe, prompted us to investigate the genetic diversity of this population and its relationship with neighboring populations. To assess the extent to which the modern Egyptian population reflects this intermediate geographic position, ten Unique Event Polymorphisms (UEPs), mapping to the nonrecombining portion of the Y chromosome, have been typed in 164 Y chromosomes from three North African populations. The analysis of these binary markers, which define 11 Y-chromosome lineages, were used to determine the haplogroup frequencies in Egyptians, Moroccan Arabs, and Moroccan Berbers and thereby define the Y-chromosome background in these regions. Pairwise comparisons with a set of 15 different populations from neighboring European, North African, and Middle Eastern populations and geographic analysis showed the absence of any significant genetic barrier in the eastern part of the Mediterranean area, suggesting that genetic variation and gene flow in this area follow the "isolation-by-distance" model. These results are in sharp contrast with the observation of a strong north-south genetic barrier in the western Mediterranean basin, defined by the Gibraltar Strait. Thus, the Y-chromosome gene pool in the modern Egyptian population reflects a mixture of European, Middle Eastern, and African characteristics, highlighting the importance of ancient and recent migration waves, followed by gene flow, in the region.

and another worldwide study of human genetic diversity

Am J Hum Genet. 2000 Mar;66(3):979-88. Related Articles, Links

The distribution of human genetic diversity: a comparison of mitochondrial, autosomal, and Y-chromosome data.

Jorde LB, Watkins WS, Bamshad MJ, Dixon ME, Ricker CE, Seielstad MT, Batzer MA.

Department of Human Genetics, University of Utah Health Sciences Center, Salt lake City, UT, 84112, USA. lbj@genetics.utah.edu

We report a comparison of worldwide genetic variation among 255 individuals by using autosomal, mitochondrial, and Y-chromosome polymorphisms. Variation is assessed by use of 30 autosomal restriction-site polymorphisms (RSPs), 60 autosomal short-tandem-repeat polymorphisms (STRPs), 13 Alu-insertion polymorphisms and one LINE-1 element, 611 bp of mitochondrial control-region sequence, and 10 Y-chromosome polymorphisms. Analysis of these data reveals substantial congruity among this diverse array of genetic systems. With the exception of the autosomal RSPs, in which an ascertainment bias exists, all systems show greater gene diversity in Africans than in either Europeans or Asians. Africans also have the largest total number of alleles, as well as the largest number of unique alleles, for most systems. GST values are 11%-18% for the autosomal systems and are two to three times higher for the mtDNA sequence and Y-chromosome RSPs. This difference is expected because of the lower effective population size of mtDNA and Y chromosomes. A lower value is seen for Y-chromosome STRs, reflecting a relative lack of continental population structure, as a result of rapid mutation and genetic drift. Africa has higher GST values than does either Europe or Asia for all systems except the Y-chromosome STRs and Alus. All systems except the Y-chromosome STRs show less variation between populations within continents than between continents. These results are reassuring in their consistency and offer broad support for an African origin of modern human populations.

and here is a review dealing with human pop gen and the issue of race

C R Acad Sci III. 1998 Jun;321(6):443-6. Related Articles, Links

Human genome diversity.

Cann HM.

Fondation Jean-Dausset, Centre d'etude du polymorphisme humain (CEPH), Paris, France. howard.cann@cephb.fr

Human genome diversity studies analyse genetic variation among individuals and between populations in order to understand the origins and evolution of anatomically modern humans (Homo sapiens sapiens). The availability of thousands of DNA polymorphisms (genetic markers) brings analytic power to these studies. Human genome diversity studies have clearly shown that the large part of genetic variability is due to differences among individuals within populations rather than to differences between populations, effectively discrediting a genetic basis of the concept of 'race'. Evidence from paleontology, archaeology and genetic diversity studies is quite consistent with an African origin of modern humans more than 100,000 years ago. The evidence favors migrations out of African as the source of the original peopling of Asia, Australia, Europe and Oceania. An international program for the scientific analysis of human genome diversity and of human evolution has been developed. The Human Genome Diversity Project (HGDP) aims to collect and preserve biologic samples from hundreds of populations throughout the world, make DNA from these samples available to scientists and distribute to the scientific community the results of DNA typing with hundreds of genetic markers.


This message is a reply to:
 Message 57 by Minnemooseus, posted 10-30-2003 3:54 AM Minnemooseus has not yet responded

Replies to this message:
 Message 60 by Peter, posted 10-30-2003 5:43 AM Mammuthus has not yet responded

  
Peter
Member (Idle past 2031 days)
Posts: 2160
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 59 of 274 (63435)
10-30-2003 4:44 AM
Reply to: Message 48 by NosyNed
10-29-2003 10:22 AM


Now I'm starting to have a problem ... need to know where
these percentiles come from.

According to the logic so far we are all chimpanzees.

Difference between human and chimp is somewhere between
1% and 5% ... which is less than variation within a
human socio-racial population -> therefore we are chimps.

...mind you, some of the people I know ....


This message is a reply to:
 Message 48 by NosyNed, posted 10-29-2003 10:22 AM NosyNed has not yet responded

    
Peter
Member (Idle past 2031 days)
Posts: 2160
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 60 of 274 (63441)
10-30-2003 5:43 AM
Reply to: Message 58 by Mammuthus
10-30-2003 4:39 AM


quote:

Here are some references. Yes, Africa has the most diversity. According to the out of Africa hypothesis of human evolution, we originated in Africa, expanded and then migrated out to colonize the rest of the world. Though there must have been a great deal of migration in and out of Africa, the end effect is that colonized areas would show less genetic diversity than the original source population i.e. Africa should have more genetic variation among populations than say Europe for example

That's not the only explanation that fits though -- is it?

Suppose humans started off somewhere other than Africa, and some
migrated INTO Africa.

Given that it's only in the last 150 years or so, that African
populations have had wide contact with each-other and non-africans
wouldn't that cause the same effects.

Europe has a pretty invader-oriented genetic history over the
last 2000 or so years (Roman occupation for hundreds of years,
Western Eurpoeans trapsing all over the place during the
various crusades ... and trade/migration around Europe had
been extensive for hundreds of years (otherwise the black death
wouldn't have spread from the orient to consume all of Europe).

Conquerors also have a tendancy to deliberatly inter-breed with
the natives to increase their power base.

Maybe all of this has been considered in the analyses and
there are good reasons that they can be neglected ????


This message is a reply to:
 Message 58 by Mammuthus, posted 10-30-2003 4:39 AM Mammuthus has not yet responded

    
Prev123
4
56
...
19NextFF
Newer Topic | Older Topic
Jump to:


Copyright 2001-2018 by EvC Forum, All Rights Reserved

™ Version 4.0 Beta
Innovative software from Qwixotic © 2019