jawhead
Banned
- Liittynyt
- 4.1.2007
- Viestejä
- 4 984
Suomalainen on suomessa syntynyt suomea ensimmäiseksi kielekseen puhuva ugrilaisen perimän omaava henkilö.
Maahanmuutto
- Keskustelun aloittaja Kalmaaja
- Aloitettu
Suomalainen on suomessa syntynyt suomea ensimmäiseksi kielekseen puhuva ugrilaisen perimän omaava henkilö.
- Liittynyt
- 28.11.2003
- Viestejä
- 515
Totta, itsekkin suomenruotsalaiset kutsuvat itseään suomenruotsalaisiksi ja heidän puolueensa on RKP. He asuvat Suomessa ja ovat Suomen kansalaisia, mutta Suomalaisia he eivät ole. Tosin suomenruotsalaisetkin omaavat enimmäkkseen "ugrilaisen perimän", mutta he ovat valinneet identiteetikseen ruotsalaisuuden.
jawhead
Banned
- Liittynyt
- 4.1.2007
- Viestejä
- 4 984
En mene varmana sanomaan mutta muistaakseni ruotsi on germaaninen kieli. Saatan olla väärässä.
- Liittynyt
- 1.2.2005
- Viestejä
- 66
Mikä ihme on tämä vastenmielisyys ruotsalaisia kohtaan? Ruotsalaiset toivat "sivistyksen" itään. Ruotsi-Suomi: ei Ruotsi hallitsi puolta Eurooppaa. Olisiko ollut nasevampaa jos Ryssät olivat olleet Ensimmäisinä. Kustaa-Adolf Ruotsi-Suomen Kuningas. Menkää kirjastoon.
- Liittynyt
- 28.11.2003
- Viestejä
- 515
Niin? Kieli on germaaninen, mutta suomenruotsalaiset ovat geneettisesti osin lähempänä Suomalaisia kuin Ruotsalaisia eli "ugrilaisia perimältään", tosin Suomalaisetkin ovat geneettisesti Indo-Eurooppalaisia yli 80 prosenttisesti.
- Liittynyt
- 28.11.2003
- Viestejä
- 515
Mikä viha? Tässähän on vain etsitty määritelmää sanalle Suomalainen, eli Suomalainen on syntyperältään Suomalainen joka puhuu äidinkielenään suomea, joku voi määritellä toisin.
Mistä tuo kumma venäläisviha, no aika paljon niiden takia on kärsitty, mutta myös Ruotsin takia. Mutta toisaalta puoli itse vouhotetaan ruotsalaisvihasta samalla kun lietsotaan taas vihaa toista ryhmää kohtaan.
Voisit mennä kirjastoon ja tutustua historiaan, itse asiassa venäläiset olivat ensin mm. raamattu, pappi ja risti ovat venäläisiä lainasanoja. Eli kristinusko tuli kai ensin idästä, myöhemmin länsi voitti. Ruotsi ei hallinnut puolta Eurooppaa.
Suomessa oli sivistystä jo ennen Ruotsia, siis tarkoitan omaa kulttuuria, suuri osa meidän "kultturista" perustuu länsimaiseen "perintöön" ja se ei suinkaan ole ruotsalaisten keksimää.
Ei ole ollut olemassa Ruotsi-Suomea oli vain Ruotsi, voisitko pistäytyä siellä kirjastossa.
Niin mitä tuosta Kustaa-Aadolfista Ruotsin kuninkaasta, halusitko kenties sanoa jotain?
Hard Justice
Dirdy birdy
- Liittynyt
- 20.10.2007
- Viestejä
- 3 083
Kuinkahan moni niistä, jotka jankkaavat sitä että ruotsia puhuvat suomalaiset eivät ole suomalaisia, pitää sankarinaan erästä umpirikkaan ruotsinsuomalaisen suvun jäsentä... Joku Ernrothien suvun miehistä se taisi olla, taidettiin jopa äänestää suurten suomalaisten joukossa hyvälle sijoitukselle ;)
Deleted member 44249
Kaupassa tuli romanirikastaja vonkaamaan sitkeesti rahaa huumeisiin. Sanoi olevansa narkkari ja tarvitsee rahaa, jupa jup :D Ja vaikka oliskin, niin piriin ym. mun rahat tietysti ekana pitää pistää!
Edit: tämä rikastaja kuuluu paikalliseen kuuluisaan romanirikastajien perheeseen, jossa hänen isoveljensä on musta lammas; suoritti peruskoulun! Siitä tehtiin dokkari ja näytettiin ylellä aikoinaan, jos joku on nähnyt. Rikastaminen alamäessä kun peruskoulukin jo suoritettu mannelta
Edit: tämä rikastaja kuuluu paikalliseen kuuluisaan romanirikastajien perheeseen, jossa hänen isoveljensä on musta lammas; suoritti peruskoulun! Siitä tehtiin dokkari ja näytettiin ylellä aikoinaan, jos joku on nähnyt. Rikastaminen alamäessä kun peruskoulukin jo suoritettu mannelta
- Liittynyt
- 29.9.2007
- Viestejä
- 340
Asiasta keppihevoseen:
http://www.youtube.com/watch?v=y9dXGJ2rYdA
Pat Condell tavallista kiukkuisempana.
Tuon saarnan jälkeen korvat punotti. Täyttä asiaa.
http://www.youtube.com/watch?v=y9dXGJ2rYdA
Pat Condell tavallista kiukkuisempana.
Tuon saarnan jälkeen korvat punotti. Täyttä asiaa.
jawhead
Banned
- Liittynyt
- 4.1.2007
- Viestejä
- 4 984
No enpä ole ainakaan minä äänestänyt koska olen vannoutunut fennomaani,
- Liittynyt
- 5.10.2006
- Viestejä
- 1 192
Äläs nyt hoppuile. Muistan lukeneeni paljonkin aiheesta ja aivan päinvastaista. Koetan etsiä.
Toisin kysyen: silmät päässä?
- Liittynyt
- 24.3.2003
- Viestejä
- 438
Edelleenkin tämä pätee teoriaan kuin teoriaan. Rotuteoria ei tässäkään suhteessa poikkea muista teorioista.
Näin varmasti on, mutta käsitätkö oikeasti että ideologisia ambitioita on kummallakin puolella? Käsi sydämmelle: Jos joku pystyisi aukottomasti todistamaan että rotuja on olemassa, niin pystyisitkö hyväksymään tuloksen? Tiedän että se olisi monelle todella kova paikka johtuen moraaliin perustuvasta ideologiasta.
No itse asiassa itse pidän rodun käsitettä aivan mielekkäänä myös ihmisillä, en tosin pysty sitä kovin vakuttavasti perustelemaan. Pyydänkin, että perustelet asian itse. Kaapeliakin varmasti kiinnostaa perustelut.
- Liittynyt
- 27.2.2004
- Viestejä
- 5 833
Syntyperältään suomalainen, äidinkielenään Suomi? Nämäkö kriteerit?
Eli esimerkiksi vietnamilaiset vanhemmat omaava, mutta Suomessa syntynyt (eli syntyperäinen suomalainen) ja suomea pääasiallisena äidinkielenään puhuva on siis suomalainen? Tai vaihtoehtoisesti voi mennä vielä pidemmälle ja kysyä onko suomessa syntynyt suomea äidinkielenään puhuva henkilö, jonka isovanhemmat ovat olleet maahanmuuttajia tai vain toinen vanhemmista, suomalainen?
Jatkokysymys, jos vastaus oli edelliseen ei: Miten ja miksi maahanmuuttajataustaisten odotetaan integroituvan ja ryhtyvän suomalaisiksi, jos heitä ei tulla koskaan sellaisiksi hyväksymään esimerkiksi ulkomuotonsa tai sukujuuriensa takia, vaikka mitä tekisivät ja kuinka haluaisivat?
- Liittynyt
- 27.2.2004
- Viestejä
- 5 833
Mitä ihmeen "toiseutta"? Ulkonäköäkö? Mikä on hyväksyttävä ulkonäkö suomalaiselle, jolloin hän ei enää edustaisi "toiseutta"? Onko tähän olemassa jotkut tarkemmatkin kriteerit? Entäs jos henkilöä ei ulkonäöltä erota suomalaisesta, mutta hänellä on silti juuria ulkomailla? Milläs perusteella tällainen "toiseutta edustava" kaveri saadaan syrjäytettyä mahdollisuudesta tulla luetuksi suomalaiseksi? Vedotaan ulkoperäisiin esi-isiin tai vaikka vääränlaiseen sukunimeen?
Ja tuohon kysymykseen vastaus löytyy alkuperäisestä tekstistä. Mutta toistetaan: Jos henkilön halutaan olevan suomalainen (suomalaiseen kulttuuriin, kieleen ja koko maahan integroitunut), mutta häntä ei sellaiseksi hyväksytä, niin onhan tuossa aika ilmeinen ristiriita. "Ole suomalainen, mutta et kuitenkaan ole suomalainen."
Ja tuohon kysymykseen vastaus löytyy alkuperäisestä tekstistä. Mutta toistetaan: Jos henkilön halutaan olevan suomalainen (suomalaiseen kulttuuriin, kieleen ja koko maahan integroitunut), mutta häntä ei sellaiseksi hyväksytä, niin onhan tuossa aika ilmeinen ristiriita. "Ole suomalainen, mutta et kuitenkaan ole suomalainen."
- Liittynyt
- 15.6.2006
- Viestejä
- 7 803
Kerro ensin meille miksei pitäisi?
parka
Banned
- Liittynyt
- 21.2.2007
- Viestejä
- 298
Ei heidän odoteta integroituvan heidän odotetaan lähtevän takaisin kotimaahansa.
Valitsit hyvin tätä aikaa kuvaavan sanan ryhtyä. Ei suomalaiseksi ryhdytä, ei kulttuuriperimää voi vain ottaa ja ryhtyä. Ryhdynpä tässä somaliksi. Ajatusmaailmansa voi valita ja vakaumuksensa voi valita ja ryhtyä. Integroituminen maahan johon muuttaa tapahtuu omaksumalla maan tavat, ei tuomalla omia tapoja ja vaatimuksia niiden noudattamisesta. Omaan kulttuuriinsa vetoaminen osoittaa jo mielestäni haluttomuutta sopeutua, varsinkin jos omat tavat sotivat maan tapoja vastaan.
- Liittynyt
- 5.10.2006
- Viestejä
- 1 192
http://en.wikipedia.org/wiki/Lewontin%27s_Fallacy
http://genomebiology.com/2002/3/7/comment/2007/
Sori spämmi..
Probably the best way to examine the issue of genetic subgrouping is through the lens of human evolution. If the human population mated at random, there would be no issue of genetic subgrouping because the chance of any individual carrying a specific gene variant would be evenly distributed around the world. For a variety of reasons, however, including geography, sociology and culture, humans have not and do not currently mate randomly, either on a global level or within countries such as the US. A clearer picture of human evolution has emerged from numerous studies over the past decade using a variety of genetic markers and involving indigenous populations from around the world. In summary, populations outside Africa derive from one or more migration events out of Africa within the last 100,000 years [5,6,7,8,9,10,11]. The greatest genetic variation occurs within Africans, with variation outside Africa representing either a subset of African diversity or newly arisen variants. Genetic differentiation between individuals depends on the degree and duration of separation of their ancestors. Geographic isolation and in-breeding (endogamy) due to social and/or cultural forces over extended time periods create and enhance genetic differentiation, while migration and inter-mating reduce it.
With this as background, it is not surprising that numerous human population genetic studies have come to the identical conclusion - that genetic differentiation is greatest when defined on a continental basis. The results are the same irrespective of the type of genetic markers employed, be they classical systems [5], restriction fragment length polymorphisms (RFLPs) [6], microsatellites [7,8,9,10,11], or single nucleotide polymorphisms (SNPs) [12]. For example, studying 14 indigenous populations from 5 continents with 30 microsatellite loci, Bowcock et al. [7] observed that the 14 populations clustered into the five continental groups, as depicted in Figure 1. The African branch included three sub-Saharan populations, CAR pygmies, Zaire pygmies, and the Lisongo; the Caucasian branch included Northern Europeans and Northern Italians; the Pacific Islander branch included Melanesians, New Guineans and Australians; the East Asian branch included Chinese, Japanese and Cambodians; and the Native American branch included Mayans from Mexico and the Surui and Karitiana from the Amazon basin. The identical diagram has since been derived by others, using a similar or greater number of microsatellite markers and individuals [8,9]. More recently, a survey of 3,899 SNPs in 313 genes based on US populations (Caucasians, African-Americans, Asians and Hispanics) once again provided distinct and non-overlapping clustering of the Caucasian, African-American and Asian samples [12]: "The results confirmed the integrity of the self-described ancestry of these individuals". Hispanics, who represent a recently admixed group between Native American, Caucasian and African, did not form a distinct subgroup, but clustered variously with the other groups. A previous cluster analysis based on a much smaller number of SNPs led to a similar conclusion: "A tree relating 144 individuals from 12 human groups of Africa, Asia, Europe and Oceania, inferred from an average of 75 DNA polymorphisms/individual, is remarkable in that most individuals cluster with other members of their regional group" [13]. Effectively, these population genetic studies have recapitulated the classical definition of races based on continental ancestry - namely African, Caucasian (Europe and Middle East), Asian, Pacific Islander (for example, Australian, New Guinean and Melanesian, and Native American.
The terms race, ethnicity and ancestry are often used interchangeably, but some have also drawn distinctions. For the purpose of this article, we define racial groups on the basis of the primary continent of origin, as discussed above (with some modifications described below). Ethnicity is a self-defined construct that may be based on geographic, social, cultural and religious grounds. It has potential meaning from the genetic perspective, provided it defines an endogamous group that can be differentiated from other such groups. Ancestry refers to the race/ethnicity of an individual's ancestors, whatever the individual's current affiliation. From the genetic perspective, the important concept is mating patterns, and the degree to which racially or ethnically defined groups remain endogamous.
The continental definitions of race and ancestry need some modification, because it is clear that migrations have blurred the strict continental boundaries. For example, individuals currently living in South Africa, although currently Africans, have very different ancestry, race and ethnicity depending on the ancestry of their forbears (for example from Europe or Asia) and the degree to which they have remained endogamous. For our purposes here, on the basis of numerous population genetic surveys, we categorize Africans as those with primary ancestry in sub-Saharan Africa; this group includes African Americans and Afro-Caribbeans. Caucasians include those with ancestry in Europe and West Asia, including the Indian subcontinent and Middle East; North Africans typically also are included in this group as their ancestry derives largely from the Middle East rather than sub-Saharan Africa. 'Asians' are those from eastern Asia including China, Indochina, Japan, the Philippines and Siberia. By contrast, Pacific Islanders are those with indigenous ancestry from Australia, Papua New Guinea, Melanesia and Micronesia, as well as other Pacific Island groups further east. Native Americans are those that have indigenous ancestry in North and South America. Populations that exist at the boundaries of these continental divisions are sometimes the most difficult to categorize simply. For example, east African groups, such as Ethiopians and Somalis, have great genetic resemblance to Caucasians and are clearly intermediate between sub-Saharan Africans and Caucasians [5]. The existence of such intermediate groups should not, however, overshadow the fact that the greatest genetic structure that exists in the human population occurs at the racial level.
Most recently, Wilson et al. [2] studied 354 individuals from 8 populations deriving from Africa (Bantus, Afro-Caribbeans and Ethiopians), Europe/Mideast (Norwegians, Ashkenazi Jews and Armenians), Asia (Chinese) and Pacific Islands (Papua New Guineans). Their study was based on cluster analysis using 39 microsatellite loci. Consistent with previous studies, they obtained evidence of four clusters representing the major continental (racial) divisions described above as African, Caucasian, Asian, and Pacific Islander. The one population in their analysis that was seemingly not clearly classified on continental grounds was the Ethiopians, who clustered more into the Caucasian group. But it is known that African populations with close contact with Middle East populations, including Ethiopians and North Africans, have had significant admixture from Middle Eastern (Caucasian) groups, and are thus more closely related to Caucasians [14]. Furthermore, the analysis by Wilson et al. [2] did not detect subgroups within the four major racial clusters (for example, it did not separate the Norwegians, Ashkenazi Jews and Armenians among the Caucasian cluster), despite known genetic differences among them. The reason is clearly that these differences are not as great as those between races and are insufficient, with the amount of data provided, to distinguish these subgroups.
Are racial differences merely cosmetic?
Two arguments against racial categorization as defined above are firstly that race has no biological basis [1,3], and secondly that there are racial differences but they are merely cosmetic, reflecting superficial characteristics such as skin color and facial features that involve a very small number of genetic loci that were selected historically; these superficial differences do not reflect any additional genetic distinctiveness [2]. A response to the first of these points depends on the definition of 'biological'. If biological is defined as genetic then, as detailed above, a decade or more of population genetics research has documented genetic, and therefore biological, differentiation among the races. This conclusion was most recently reinforced by the analysis of Wilson et al. [2]. If biological is defined by susceptibility to, and natural history of, a chronic disease, then again numerous studies over past decades have documented biological differences among the races. In this context, it is difficult to imagine that such differences are not meaningful. Indeed, it is difficult to conceive of a definition of 'biological' that does not lead to racial differentiation, except perhaps one as extreme as speciation.
A forceful presentation of the second point - that racial differences are merely cosmetic - was given recently in an editorial in the New England Journal of Medicine [1]: "Such research mistakenly assumes an inherent biological difference between black-skinned and white-skinned people. It falls into error by attributing a complex physiological or clinical phenomenon to arbitrary aspects of external appearance. It is implausible that the few genes that account for such outward characteristics could be meaningfully linked to multigenic diseases such as diabetes mellitus or to the intricacies of the therapeutic effect of a drug." The logical flaw in this argument is the assumption that the blacks and whites in the referenced study differ only in skin pigment. Racial categorizations have never been based on skin pigment, but on indigenous continent of origin. For example, none of the population genetic studies cited above, including the study of Wilson et al. [2], used skin pigment of the study subjects, or genetic loci related to skin pigment, as predictive variables. Yet the various racial groups were easily distinguishable on the basis of even a modest number of random genetic markers; furthermore, categorization is extremely resistant to variation according to the type of markers used (for example, RFLPs, microsatellites or SNPs).
Genetic differentiation among the races has also led to some variation in pigmentation across races, but considerable variation within races remains, and there is substantial overlap for this feature. For example, it would be difficult to distinguish most Caucasians and Asians on the basis of skin pigment alone, yet they are easily distinguished by genetic markers. The author of the above statement [1] is in error to assume that the only genetic differences between races, which may differ on average in pigmentation, are for the genes that determine pigmentation.
Common versus rare alleles
Despite the evidence for genetic differentiation among the five major races, as defined above, numerous studies have shown that local populations retain a great deal of genetic variation. Analysis of variance has led to estimates of 10% for the proportion of variance due to average differences between races, and 75% of the variance due to genetic variation within populations. Comparable estimates have been obtained for classical blood markers [15,16], microsatellites [17], and SNPs [12]. Unfortunately, these analysis of variance estimates have also led to misunderstandings or misinterpretations. Because of the large amount of variation observed within races versus between races, some commentators have denied genetic differentiation between the races; for example, "Genetic data ... show that any two individuals within a particular population are as different genetically as any two people selected from any two populations in the world." [18]. This assertion is both counter-intuitive and factually incorrect [12,13]. If it were true, it would be impossible to create discrete clusters of humans (that end up corresponding to the major races), for example as was done by Wilson et al. [2], with even as few as 20 randomly chosen genetic markers. Two Caucasians are more similar to each other genetically than a Caucasian and an Asian.
In these variance assessments, it is also important to consider the frequency of the allelic variants examined. These studies are based primarily on common alleles, and may not reflect the degree of differentiation between races for rare alleles. This is an important concern because alleles underlying disease susceptibility, especially deleterious diseases, may be less frequent than randomly selected alleles. Similarly, it has also been shown that among different classes of SNPs, those that lead to non-conservative amino-acid substitutions (which most frequently are associated with clinical outcomes) occur least often, and when they do occur they tend to have lower allele frequencies than non-coding or synonymous coding changes [12,19,20].
It is likely that genetic differentiation among races is enhanced for disease-predisposing alleles because such alleles tend to be in the lower frequency range. It is well known that rarer alleles are subject to greater fluctuation in frequency due to genetic drift than common alleles. Indeed, for most Mendelian diseases, even higher frequency alleles are found only in specific races (for example, cystic fibrosis and hemochromatosis in Caucasians). Furthermore, recent SNP surveys of the different races have shown that lower frequency variants are much more likely to be specific to a single race or shared by only two races than are common variants [12,19,20]. In one study, only 21% of 3,899 SNPs were found to be pan-ethnic, and some race-specific SNPs were found to have a frequency greater than 25% [12].
Admixture and genetic categorization in the United States
Most population genetic studies that focus on human evolution and the relatedness of people, including the ones cited above, utilize indigenous groups from the various continents. These groups would not necessarily adequately depict the US population, for example, where admixture between races has occurred over many centuries. Nonetheless, during the same period of time, as well as currently, mating patterns are far from random. The tendency toward endogamy is reflected within the 2000 US Census [21], which allowed individuals to report themselves to be of a single race or of mixed race. Six racial categories were provided (White; Black or African American; American Indian and Alaska Native; Asian; Native Hawaiian and other Pacific Islander; Some other race). In response to this question, 97.6% of subjects reported themselves to be of one race, while 2.4% reported themselves to be of more than one race; 75% reported themselves as White, 12.3% as Black or African American, 3.6% as Asian, 1% as American Indian or Alaska Native, 0.1% as Hawaiian or Pacific Islander; and 5.5% of other race. Of the 5.5% who reported themselves as 'other race', most (97%) also reported themselves to be Hispanic. According to these numbers, if mating were at random with respect to these racial categories, 42% of individuals would result from 'mixed' matings and hence derive from more than one race, as opposed to the 2.4% reported. These figures highlight the strong deviation from random mating in the US.
What are the implications of these census results and the admixture that has occurred in the US population for genetic categorization in biomedical research studies in the US? Gene flow from non-Caucasians into the US Caucasian population has been modest. On the other hand, gene flow from Caucasians into African Americans has been greater; several studies have estimated the proportion of Caucasian admixture in African Americans to be approximately 17%, ranging regionally from about 12% to 23% [22]. Thus, despite the admixture, African Americans remain a largely African group, reflecting primarily their African origins from a genetic perspective. Asians and Pacific Islanders have been less influenced by admixture and again closely represent their indigenous origins. The same is true for Native Americans, although some degree of Caucasian admixture has occurred in this group as well [23].
The most complex group is made up of those who self-identify as Hispanic/Latino. The US Census did not consider this group as a separate race, although 42% of respondents who considered themselves Hispanic checked the category 'other race' for the racial question, while 48% checked 'White'. Hispanics are typically a mix of Native American, Caucasian and African/African American, with the relative proportions varying regionally. Southwest Hispanics, who are primarily Mexican-American, appear to be largely Caucasian and Native American; recent admixture estimates are 39% Native American, 58% Caucasian and 3% African [24]. By contrast, East Coast Hispanics are largely Caribbean in origin, and have a greater proportion African admixture [25]. Thus, depending on geography, self-identified Hispanics could aggregate genetically with Caucasians, Native Americans, African Americans or form their own cluster.
The persistence of genetic differentiation among these US racial groups (as defined by the US Census) has also been verified recently in a study of nearly 4,000 SNPs in 313 genes [12]. These authors found distinct clusters for Caucasian Americans, African Americans and Asian Americans; the Hispanic Americans did not form a separate cluster but were either grouped with Caucasians or not easily classified. Although the US Census results suggest the large majority of individuals can be categorized into a single ancestral group, there remain individuals of mixed ancestry who will not be easily categorized by any simple system of finite, discrete categories. On the other hand, such individuals can be particularly informative in epidemiologic studies focused on differentiating genetic versus environmental sources for racial/ethnic difference, as we describe further below.
http://genomebiology.com/2002/3/7/comment/2007/
Sori spämmi..
Probably the best way to examine the issue of genetic subgrouping is through the lens of human evolution. If the human population mated at random, there would be no issue of genetic subgrouping because the chance of any individual carrying a specific gene variant would be evenly distributed around the world. For a variety of reasons, however, including geography, sociology and culture, humans have not and do not currently mate randomly, either on a global level or within countries such as the US. A clearer picture of human evolution has emerged from numerous studies over the past decade using a variety of genetic markers and involving indigenous populations from around the world. In summary, populations outside Africa derive from one or more migration events out of Africa within the last 100,000 years [5,6,7,8,9,10,11]. The greatest genetic variation occurs within Africans, with variation outside Africa representing either a subset of African diversity or newly arisen variants. Genetic differentiation between individuals depends on the degree and duration of separation of their ancestors. Geographic isolation and in-breeding (endogamy) due to social and/or cultural forces over extended time periods create and enhance genetic differentiation, while migration and inter-mating reduce it.
With this as background, it is not surprising that numerous human population genetic studies have come to the identical conclusion - that genetic differentiation is greatest when defined on a continental basis. The results are the same irrespective of the type of genetic markers employed, be they classical systems [5], restriction fragment length polymorphisms (RFLPs) [6], microsatellites [7,8,9,10,11], or single nucleotide polymorphisms (SNPs) [12]. For example, studying 14 indigenous populations from 5 continents with 30 microsatellite loci, Bowcock et al. [7] observed that the 14 populations clustered into the five continental groups, as depicted in Figure 1. The African branch included three sub-Saharan populations, CAR pygmies, Zaire pygmies, and the Lisongo; the Caucasian branch included Northern Europeans and Northern Italians; the Pacific Islander branch included Melanesians, New Guineans and Australians; the East Asian branch included Chinese, Japanese and Cambodians; and the Native American branch included Mayans from Mexico and the Surui and Karitiana from the Amazon basin. The identical diagram has since been derived by others, using a similar or greater number of microsatellite markers and individuals [8,9]. More recently, a survey of 3,899 SNPs in 313 genes based on US populations (Caucasians, African-Americans, Asians and Hispanics) once again provided distinct and non-overlapping clustering of the Caucasian, African-American and Asian samples [12]: "The results confirmed the integrity of the self-described ancestry of these individuals". Hispanics, who represent a recently admixed group between Native American, Caucasian and African, did not form a distinct subgroup, but clustered variously with the other groups. A previous cluster analysis based on a much smaller number of SNPs led to a similar conclusion: "A tree relating 144 individuals from 12 human groups of Africa, Asia, Europe and Oceania, inferred from an average of 75 DNA polymorphisms/individual, is remarkable in that most individuals cluster with other members of their regional group" [13]. Effectively, these population genetic studies have recapitulated the classical definition of races based on continental ancestry - namely African, Caucasian (Europe and Middle East), Asian, Pacific Islander (for example, Australian, New Guinean and Melanesian, and Native American.
The terms race, ethnicity and ancestry are often used interchangeably, but some have also drawn distinctions. For the purpose of this article, we define racial groups on the basis of the primary continent of origin, as discussed above (with some modifications described below). Ethnicity is a self-defined construct that may be based on geographic, social, cultural and religious grounds. It has potential meaning from the genetic perspective, provided it defines an endogamous group that can be differentiated from other such groups. Ancestry refers to the race/ethnicity of an individual's ancestors, whatever the individual's current affiliation. From the genetic perspective, the important concept is mating patterns, and the degree to which racially or ethnically defined groups remain endogamous.
The continental definitions of race and ancestry need some modification, because it is clear that migrations have blurred the strict continental boundaries. For example, individuals currently living in South Africa, although currently Africans, have very different ancestry, race and ethnicity depending on the ancestry of their forbears (for example from Europe or Asia) and the degree to which they have remained endogamous. For our purposes here, on the basis of numerous population genetic surveys, we categorize Africans as those with primary ancestry in sub-Saharan Africa; this group includes African Americans and Afro-Caribbeans. Caucasians include those with ancestry in Europe and West Asia, including the Indian subcontinent and Middle East; North Africans typically also are included in this group as their ancestry derives largely from the Middle East rather than sub-Saharan Africa. 'Asians' are those from eastern Asia including China, Indochina, Japan, the Philippines and Siberia. By contrast, Pacific Islanders are those with indigenous ancestry from Australia, Papua New Guinea, Melanesia and Micronesia, as well as other Pacific Island groups further east. Native Americans are those that have indigenous ancestry in North and South America. Populations that exist at the boundaries of these continental divisions are sometimes the most difficult to categorize simply. For example, east African groups, such as Ethiopians and Somalis, have great genetic resemblance to Caucasians and are clearly intermediate between sub-Saharan Africans and Caucasians [5]. The existence of such intermediate groups should not, however, overshadow the fact that the greatest genetic structure that exists in the human population occurs at the racial level.
Most recently, Wilson et al. [2] studied 354 individuals from 8 populations deriving from Africa (Bantus, Afro-Caribbeans and Ethiopians), Europe/Mideast (Norwegians, Ashkenazi Jews and Armenians), Asia (Chinese) and Pacific Islands (Papua New Guineans). Their study was based on cluster analysis using 39 microsatellite loci. Consistent with previous studies, they obtained evidence of four clusters representing the major continental (racial) divisions described above as African, Caucasian, Asian, and Pacific Islander. The one population in their analysis that was seemingly not clearly classified on continental grounds was the Ethiopians, who clustered more into the Caucasian group. But it is known that African populations with close contact with Middle East populations, including Ethiopians and North Africans, have had significant admixture from Middle Eastern (Caucasian) groups, and are thus more closely related to Caucasians [14]. Furthermore, the analysis by Wilson et al. [2] did not detect subgroups within the four major racial clusters (for example, it did not separate the Norwegians, Ashkenazi Jews and Armenians among the Caucasian cluster), despite known genetic differences among them. The reason is clearly that these differences are not as great as those between races and are insufficient, with the amount of data provided, to distinguish these subgroups.
Are racial differences merely cosmetic?
Two arguments against racial categorization as defined above are firstly that race has no biological basis [1,3], and secondly that there are racial differences but they are merely cosmetic, reflecting superficial characteristics such as skin color and facial features that involve a very small number of genetic loci that were selected historically; these superficial differences do not reflect any additional genetic distinctiveness [2]. A response to the first of these points depends on the definition of 'biological'. If biological is defined as genetic then, as detailed above, a decade or more of population genetics research has documented genetic, and therefore biological, differentiation among the races. This conclusion was most recently reinforced by the analysis of Wilson et al. [2]. If biological is defined by susceptibility to, and natural history of, a chronic disease, then again numerous studies over past decades have documented biological differences among the races. In this context, it is difficult to imagine that such differences are not meaningful. Indeed, it is difficult to conceive of a definition of 'biological' that does not lead to racial differentiation, except perhaps one as extreme as speciation.
A forceful presentation of the second point - that racial differences are merely cosmetic - was given recently in an editorial in the New England Journal of Medicine [1]: "Such research mistakenly assumes an inherent biological difference between black-skinned and white-skinned people. It falls into error by attributing a complex physiological or clinical phenomenon to arbitrary aspects of external appearance. It is implausible that the few genes that account for such outward characteristics could be meaningfully linked to multigenic diseases such as diabetes mellitus or to the intricacies of the therapeutic effect of a drug." The logical flaw in this argument is the assumption that the blacks and whites in the referenced study differ only in skin pigment. Racial categorizations have never been based on skin pigment, but on indigenous continent of origin. For example, none of the population genetic studies cited above, including the study of Wilson et al. [2], used skin pigment of the study subjects, or genetic loci related to skin pigment, as predictive variables. Yet the various racial groups were easily distinguishable on the basis of even a modest number of random genetic markers; furthermore, categorization is extremely resistant to variation according to the type of markers used (for example, RFLPs, microsatellites or SNPs).
Genetic differentiation among the races has also led to some variation in pigmentation across races, but considerable variation within races remains, and there is substantial overlap for this feature. For example, it would be difficult to distinguish most Caucasians and Asians on the basis of skin pigment alone, yet they are easily distinguished by genetic markers. The author of the above statement [1] is in error to assume that the only genetic differences between races, which may differ on average in pigmentation, are for the genes that determine pigmentation.
Common versus rare alleles
Despite the evidence for genetic differentiation among the five major races, as defined above, numerous studies have shown that local populations retain a great deal of genetic variation. Analysis of variance has led to estimates of 10% for the proportion of variance due to average differences between races, and 75% of the variance due to genetic variation within populations. Comparable estimates have been obtained for classical blood markers [15,16], microsatellites [17], and SNPs [12]. Unfortunately, these analysis of variance estimates have also led to misunderstandings or misinterpretations. Because of the large amount of variation observed within races versus between races, some commentators have denied genetic differentiation between the races; for example, "Genetic data ... show that any two individuals within a particular population are as different genetically as any two people selected from any two populations in the world." [18]. This assertion is both counter-intuitive and factually incorrect [12,13]. If it were true, it would be impossible to create discrete clusters of humans (that end up corresponding to the major races), for example as was done by Wilson et al. [2], with even as few as 20 randomly chosen genetic markers. Two Caucasians are more similar to each other genetically than a Caucasian and an Asian.
In these variance assessments, it is also important to consider the frequency of the allelic variants examined. These studies are based primarily on common alleles, and may not reflect the degree of differentiation between races for rare alleles. This is an important concern because alleles underlying disease susceptibility, especially deleterious diseases, may be less frequent than randomly selected alleles. Similarly, it has also been shown that among different classes of SNPs, those that lead to non-conservative amino-acid substitutions (which most frequently are associated with clinical outcomes) occur least often, and when they do occur they tend to have lower allele frequencies than non-coding or synonymous coding changes [12,19,20].
It is likely that genetic differentiation among races is enhanced for disease-predisposing alleles because such alleles tend to be in the lower frequency range. It is well known that rarer alleles are subject to greater fluctuation in frequency due to genetic drift than common alleles. Indeed, for most Mendelian diseases, even higher frequency alleles are found only in specific races (for example, cystic fibrosis and hemochromatosis in Caucasians). Furthermore, recent SNP surveys of the different races have shown that lower frequency variants are much more likely to be specific to a single race or shared by only two races than are common variants [12,19,20]. In one study, only 21% of 3,899 SNPs were found to be pan-ethnic, and some race-specific SNPs were found to have a frequency greater than 25% [12].
Admixture and genetic categorization in the United States
Most population genetic studies that focus on human evolution and the relatedness of people, including the ones cited above, utilize indigenous groups from the various continents. These groups would not necessarily adequately depict the US population, for example, where admixture between races has occurred over many centuries. Nonetheless, during the same period of time, as well as currently, mating patterns are far from random. The tendency toward endogamy is reflected within the 2000 US Census [21], which allowed individuals to report themselves to be of a single race or of mixed race. Six racial categories were provided (White; Black or African American; American Indian and Alaska Native; Asian; Native Hawaiian and other Pacific Islander; Some other race). In response to this question, 97.6% of subjects reported themselves to be of one race, while 2.4% reported themselves to be of more than one race; 75% reported themselves as White, 12.3% as Black or African American, 3.6% as Asian, 1% as American Indian or Alaska Native, 0.1% as Hawaiian or Pacific Islander; and 5.5% of other race. Of the 5.5% who reported themselves as 'other race', most (97%) also reported themselves to be Hispanic. According to these numbers, if mating were at random with respect to these racial categories, 42% of individuals would result from 'mixed' matings and hence derive from more than one race, as opposed to the 2.4% reported. These figures highlight the strong deviation from random mating in the US.
What are the implications of these census results and the admixture that has occurred in the US population for genetic categorization in biomedical research studies in the US? Gene flow from non-Caucasians into the US Caucasian population has been modest. On the other hand, gene flow from Caucasians into African Americans has been greater; several studies have estimated the proportion of Caucasian admixture in African Americans to be approximately 17%, ranging regionally from about 12% to 23% [22]. Thus, despite the admixture, African Americans remain a largely African group, reflecting primarily their African origins from a genetic perspective. Asians and Pacific Islanders have been less influenced by admixture and again closely represent their indigenous origins. The same is true for Native Americans, although some degree of Caucasian admixture has occurred in this group as well [23].
The most complex group is made up of those who self-identify as Hispanic/Latino. The US Census did not consider this group as a separate race, although 42% of respondents who considered themselves Hispanic checked the category 'other race' for the racial question, while 48% checked 'White'. Hispanics are typically a mix of Native American, Caucasian and African/African American, with the relative proportions varying regionally. Southwest Hispanics, who are primarily Mexican-American, appear to be largely Caucasian and Native American; recent admixture estimates are 39% Native American, 58% Caucasian and 3% African [24]. By contrast, East Coast Hispanics are largely Caribbean in origin, and have a greater proportion African admixture [25]. Thus, depending on geography, self-identified Hispanics could aggregate genetically with Caucasians, Native Americans, African Americans or form their own cluster.
The persistence of genetic differentiation among these US racial groups (as defined by the US Census) has also been verified recently in a study of nearly 4,000 SNPs in 313 genes [12]. These authors found distinct clusters for Caucasian Americans, African Americans and Asian Americans; the Hispanic Americans did not form a separate cluster but were either grouped with Caucasians or not easily classified. Although the US Census results suggest the large majority of individuals can be categorized into a single ancestral group, there remain individuals of mixed ancestry who will not be easily categorized by any simple system of finite, discrete categories. On the other hand, such individuals can be particularly informative in epidemiologic studies focused on differentiating genetic versus environmental sources for racial/ethnic difference, as we describe further below.