Long time ghost and finally a poster. I've been reading a lot of the post concerning the indeginous nature of Berbers in particular the Riffian and Kabyle Berbers aka the "White Berbers" and noticed that posters haven't addressed an important factor in genetics and geography. North Africa actually has very cold regions and in the Atlas Mountans which are the ancestral home of the berber populations temperatures can drop below zero. I believe (and please forgive me not for more soundly verifying this first) that it takes over 10 or more generations for the climate of a place to affect the skin tone complexion of human beings. With this as a factor and also considering East African Phenotypical factors isn't it quite possible that the white berber appearance is one that is as just likely a result of them living in one of the coldest region of africa vs. Foreign admixture or a combination of the two factors ???
Posted by Quetzalcoatl (Member # 12742) on :
quote:Originally posted by Dunkin-Man: Hey Y'all
Long time ghost and finally a poster. I've been reading a lot of the post concerning the indeginous nature of Berbers in particular the Riffian and Kabyle Berbers aka the "White Berbers" and noticed that posters haven't addressed an important factor in genetics and geography. North Africa actually has very cold regions and in the Atlas Mountans which are the ancestral home of the berber populations temperatures can drop below zero. I believe (and please forgive me not for more soundly verifying this first) that it takes over 10 or more generations for the climate of a place to affect the skin tone complexion of human beings. With this as a factor and also considering East African Phenotypical factors isn't it quite possible that the white berber appearance is one that is as just likely a result of them living in one of the coldest region of africa vs. Foreign admixture or a combination of the two factors ???
White skin is not an adaptation to cold. It is an adaptation to the lack of sunshine and its effects on the amount and synthesis of vitamin D. In any case, it takes a lot more than 10 generations for a genetic mutation to spread to a whole breeding population. Thirdly, just exposure to a particular environmental condition is not sufficient, a genetic mutation that promotes greater reproductive success in this particular environment is a necessary component.
Posted by Djehuti (Member # 6698) on :
^ Understandably this topic was addressed a couple of times before, and the answers given. But it's a been a while and I don't feel like going through the archives (since no search engine).
Posted by Doug M (Member # 7650) on :
quote:Originally posted by Dunkin-Man: Hey Y'all
Long time ghost and finally a poster. I've been reading a lot of the post concerning the indeginous nature of Berbers in particular the Riffian and Kabyle Berbers aka the "White Berbers" and noticed that posters haven't addressed an important factor in genetics and geography. North Africa actually has very cold regions and in the Atlas Mountans which are the ancestral home of the berber populations temperatures can drop below zero. I believe (and please forgive me not for more soundly verifying this first) that it takes over 10 or more generations for the climate of a place to affect the skin tone complexion of human beings. With this as a factor and also considering East African Phenotypical factors isn't it quite possible that the white berber appearance is one that is as just likely a result of them living in one of the coldest region of africa vs. Foreign admixture or a combination of the two factors ???
I think you are missing the crux of the argument.
There are many misconceptions about Berber speakers that can be summarized as follows:
1) Berber is a language not an ethnic group or single phenotype.
2) Different populations with different phenotypes and ethnicities speak the Berber language.
3) All Berber speakers are not white. All Berber speakers are not black either.
4) The ancestral homeland of all Berber speakers is not the Atlas Mountains.
5) The Berber language originated in East Africa and the populations of the Sahara.
6) The populations of East Africa and the Sahara are ANCESTRAL to North African populations.
7) Historically MOST Berber speakers lived in the Sahara. Some moved to the coast and stuck to the lush OASES and VALLEYS to cultivate crops when the Sahara dried up.
8) These Berber speakers did not move to the Mountains until the invasions of the Muslims DROVE them there.
9) Some Berber speakers have more foreign ancestry than others.
10) There are a variety of types of Berber speakers all of whom are connected by being Berber speakers and sharing a African cultural base, but who vary across time and space based on history and population movements.
Posted by rasol (Member # 4592) on :
quote:Originally posted by Dunkin-Man: Hey Y'all
Long time ghost and finally a poster. I've been reading a lot of the post concerning the indeginous nature of Berbers in particular the Riffian and Kabyle Berbers aka the "White Berbers" and noticed that posters haven't addressed an important factor in genetics and geography. North Africa actually has very cold regions and in the Atlas Mountans which are the ancestral home of the berber populations temperatures can drop below zero.
Temperature per se has no bearing on skin color.
Skin color is a response to UV radiation. Even the Altas Mountains have relatively high levels of UV, compared to Northern Eurasia.
quote: I believe (and please forgive me not for more soundly verifying this first) that it takes over 10 or more generations for the climate of a place to affect the skin tone complexion of human beings.
I don't know how this can be quantified exactly.
quote: With this as a factor and also considering East African Phenotypical factors isn't it quite possible that the white berber appearance is one that is as just likely a result of them living in one of the coldest region of africa vs. Foreign admixture or a combination of the two factors
As you note in your last sentense, 'mixture' and 'environment' are not mutually exclusive.
I would note that you can say the same for olive skinned Southern Europeans.
a) they are darker than northern europeans.
b) they live in a sunnier climate that is less likely to favor depigmentation.
c) they have African paternal lineages in substantial degree [just like the kabyle have European maternal lineages].
Now to what degree is darker skin in southern Euros and adaptation, and to what degree is it the result of admixture?
Difficult to say.
To date we know of two *independant* instances that create a condition of pale skin, and both require northerly latitutes [again temperature and altitude is irrelevant].
One is specific to Europeans, and the other is specific to North East Asians.
In the case of NorthEast Asians this is difinite proof that their light skins do not derive from admixture with Europeans.
In constrast there have been no unique depigmentation mutations found amongst the leucoderm Kabyle or other light skinned groups.
Note though that even if the genes that cause some of them to be pale skinned derive from Europe - it could certainly be said that climate factors in allowing said genes to proliferate.
Posted by Mystery Solver (Member # 9033) on :
quote:Originally posted by rasol:
In the case of NorthEast Asians this is difinite proof that their light skins do not derive from admixture with Europeans.
In constrast there have been no unique depigmentation mutations found amongst the leucoderm Kabyle or other light skinned groups.
Absolutely. Recap:
Variations in the “SLC24A5” gene, as mentioned in the intro article, the “TYR” gene, the “OCA2“, the “ASIP“, and to some extent those seen in the MC1R gene, Kittles et al. have noted other genes "MATP C374G", “ADAM17“, “ATRN“, and “DCT” the mutations of which are deemed to have to had influence in promoting paleness…
Taken together (with the results of previous admixture mapping studies), these results point to the importance of several genes in shaping the pigmentation phenotype and a complex evolutionary history involving strong selection. Polymorphisms in 2 genes, ASIP and OCA2, may play a shared role in shaping light and dark pigmentation across the globe, whereas SLC24A5, MATP, and TYR have a predominant role in the evolution of light skin in Europeans but not in East Asians. These findings support a case for the recent convergent evolution of a lighter pigmentation in Europeans and East Asians…
Pairwise Fst estimates for the ASIP A8818G and OCA2 A355G SNPs tentatively suggest a pattern of divergence between 4 populations (Europeans, East Asians, Native Americans, and South Asians) and the relatively more darkly pigmented populations of West Africa and Island Melanesia, or possibly only between West Africans and all other populations. At both loci, West Africans and Island Melanesians have higher frequencies of the ancestral alleles than the other 4 populations. Pairwise locus-specific Fst values falling in the top 5% of the empirical distributions are observed between West Africans and 3 other populations (South Asians, Native Americans, and Europeans) at ASIP A8818G. Fst values between West Africans and East Asians at this locus are elevated but do not reach our cutoff value of 5% (Fst = .489, P = .065). At OCA2 A355G, only West Africans and Europeans show Fst values falling into the top fifth percentile of relevant comparisons (Fst = .516, P<.05). The low pair wise Fst values and higher frequency of ancestral alleles at both SNPs studied in these loci between West Africans and Island Melanesians hint that dark pigmentation associated with both loci in these populations may have a common evolutionary origin (Mean Fst (WA-IM) = .182; ASIP A8818G Fst (WA-IM) = .260, P = .282; OCA2 A355G Fst (WA-IM) = .101, P=.525).
Continuing with regards to OCA2 gene, we are told…
In contrast, the ancestral allele associated with dark pigmentation has a shared high frequency in sub-Sharan African and Island Melanesians. A notable exception is the relatively lightly pigmented San population of Southern Africa where the derived allele predominates (93%), although this may be simply due to small sample size (n=14).
The distributions of the derived and ancestral alleles at TYR A192C, MAPT C374G, and SLC24A5 A111G are consistent with Fst results suggesting strong European specific divergence at these loci. The derived allele at TYR, 192*A (previously linked with lighter pigmentation [Shriver et al. 2003]), has a frequency of 38% among European populations but a frequency only 14% among non-Europeans. The differences between Europeans and non-Europeans for the MAPT 374*G and SLC24A5 111*A alleles (both derived alleles associated with lighter pigmentation) were even more striking (MAT [European] = 87%; MATP [non-European] = 17%; SLC24A5 [European] = 100%; SLC24A5 [non-European] = 46%). The frequency of the SLC24A5 111*A allele outside of Europe is largely accounted for by high frequencies in geographically proximate populations in northern Africa, the Middle East, and Pakistan (ranging from 62% to 100%).
By way of negative Tajima D values, which when negative indicate selective pressure, or more specifically - “directional selection”, the authors continue…
These data confirm the unusual European-specific patterns at MATP and SLC24A5. Both genes display long range (consecutive windows) and significant indications of positive selection for all 3 statistics. In contrast, there is little evidence of a European-specific pattern in the TYR locus although the non-synonymous TYR A192C SNP does individually show a strongly significant CEU-LSBL (P<.003) in the HapMap data as in our original findings. The contrast may be explained by the limitations of our HapMap sliding windows analyses, whereby adjacent SNPs are averaged using a method that does not consider Haplotype structure.
East Asians showed relatively stronger selection for a different set of genes…
…In particular, 2 genes (ADAM17 and ATRN) showed East Asian-specific signatures comparable in strength with those observed for MATP and SLC24A5 in Europeans.
While…
The ADTB3A gene also shows a strong and focused signature of positive selection in Africans...
Many hypotheses predict that natural selection will eliminate genetic variants associated with lighter skin in the regions of high UVR as a protection against photo damage (e.g., sunburn, melanoma, and basal and squamous cell carcinomas) (Blum 1961; Kollias et al. 1991) and folic acid photo degradation (Branda and Eaton 1978; Jablonski and Chaplin 2000). The photo protective properties of a highly melanized skin and the recent African origin of modern humans suggest that the ancestral phenotype is one of the relatively dark skin (Jablonski and Chaplin 2000; Rogers et al. 2004). If dark skin is the ancestral phenotype, then we may assume that the first migrants out of Africa were relatively darkly pigmented…
There are 2 primary explanations for the evoluktion of lighter skin in regions of low UVR:
1)The first suggests that light skin is merely due to the relaxation of functional constraint and that derived alleles associated with lighter pigmentation may have simply drifted to high frequency in the absence of strong purifying selection (Brace 1963).
2)The second explanation suggests that in lower UVR regions, positive selection would have favored mutations leading to lighter skin as a way to maximize cutaneous vitamin D synthesis (Rana et al. 1999; Jablonski and Chaplin 200). Given the relatively recent arrival and divergence of humans in and across Europe and Asia, the most parsimonious evolution of light skin would involve such mutations arising in a proto-Eurasian population soon after humans left Africa.
Consequently, these mutations should be shared between modern Asian and European populations. Alternatively, if separate existing functional variants were driven to high frequency in East Asian and Europeans or independent de novo mutations arose and were selected in each population after divergence of Europeans and Asians, then these would be obvious as high allele frequency differences between modern European and East Asian populations. Reduced levels of heterozygosity surrounding the SLC24A5 A111G polymorphism in the European, but not East Asian, HapMap populations support the latter hypothesis (Lamason et al. 2005), as do reduced polymorphism levels based on full resequencing data from MATP in populations of European descent (Soejima et al. 2005).
So basically, while “SLC24A5, MATP, and TYR have a predominant role in the evolution of light skin in Europeans,” the ADAM17, ATRN, and DCT appear to play a dominant role in the evolution of light skin in East Asians.
Current archeological evidence suggests human presence in Island Melanesia by at least 40ky ago and in other parts of Sahul by at least 45ky ago (O’Connell and Allen 2004). If the original migrants to Oceania arrived there via a corridor of relatively high UVR, then we might expect their descendants to share ancestral pigmentation variants with African populations. However, if the ancestors of modern day Island Melanesians spent a significant amount of time in low-UVR, then it is possible that mutations associated with lighter pigmentation could have accumulated and a readaptation to high-UVR conditions would have been necessary, leading to potential divergence between Island Melanesians and Africans at functional pigmentation loci. In actuality, both of these scenarios may apply, as we know that modern Island Melanesian populations are descended broth early migrants (arriving 40ky ago) as well as later proto-Austronesian-speaking peoples from a southeast Asian homeland ~ 3,200 years ago (Spriggs 1997).
The discordance between our Fst -based divergence values and allele frequencies in the Melanesian CEPH populations at ASIP largely stem from the relatively low frequency of the ancestral allele in the 2 CEPH Island Melanesian populations relative to our original Island Melanesian sample. These discrepancies make it difficult to determine if ASIP truly underlies broad pigmentation differences between darkly and lightly pigmented populations or instead interoperation variation at this locus can largely be explained by differences between the frequencies of the ASIP ancestral allele in our original Island Melanesian sample and the Melanesian samples from the CEPH panel may be indicative of both the complex demographic history of Island Melanesia (involving several migratory events (Spriggs 1997) and probable extensive genetic drift (Friendlaender 1975, 1987) as well as the importance of multiple loci in determining pigmentation phenotype…
^Thus possible further extensions of variations detected amongst Melanesians can be explained by successive demographic events After their African ancestors migrated over 40ky ago. The “original Melanesian sample” appears to have more ancestral pigmentation genes in common with tropical Africans, which is to be expected given that they are direct descendants of the earliest Eurasians, as demonstrated as follows with the OCA2 gene…
In general, the derived allele (associated with lighter pigmentation) is most common in Europeans and East Asians, and the ancestral allele predominates in sub-Saharan Africa and Island Melanesia.
The mutations in the OCA2 gene may well have implications on imparting paleness, as demonstrated in the south African San people…
The lightly pigmented hunter-gatherer San populations of Southern Africa is exceptional in having a high frequency of the derived allele relative to geographically proximate and more darkly pigmented African populations (Jablonski and Chaplin 2000), further supporting the importance of OCA2 in regulating normal variation in pigmentation. The widespread distribution of the derived allele in the CEPH-Diversity Panel suggests that it is not necessarily a new mutation, nor has it been restricted to a specific geographic area.
While it seems plausible that the “derived” OCA2 gene came to being before the out-of-Africa migration that give rise to modern Eurasians, it doesn’t appear that this derived allele was necessarily widespread, and may well have been later on selected for in European and East Asians…
Interestingly, derived allele frequencies at this locus are quite different between Native American (15%) and East Asian populations (45%), suggesting that perhaps the derived allele at this locus did not reach very high frequencies in East Asians until after the colonization of the Americas.
Contrast the situation with OCA2 gene with that of the MATP 374*G allele…
The virtual absence of MATP 374*G-derived allele in the sub-Saharan African populations that we examined in the CEPH-Diversity Panel is consistent with the origin of this mutation outside of Africa AFTER the divergence of modern Asians and Europeans.
Contrasting that of the “derived” SLC24 A5 [as in the case with the “derived” OCA2 allele] , where two possible scenarios arise…
In contrast, the SLC24 A5 11*A-derived allele is found at low frequencies in several sub-Saharan populations including the West African Mandinka and Yoruba, the Southern African San, and South West Bantu.
1)The relatively high frequencies of the derived allele in Central Asian, Middle Eastern, and North Africa seem likely to be due to recent gene flow from European and Central Asian populations.
2)Alternatively, the derived allele may have lost in the ancestors of modern East Asians but retained in the ancestral European populations. The allele then rose to high frequency in Europeans following the divergence of Europeans and East Asian ancestral groups.
The different mechanism of the evolution of light skin in Europeans and East Asians apparent from genetic examination, supports the understanding that evolution of pale skin came very late, because if had occurred prior to the divergence of the Europeans and East Asians, then it seems highly plausible that they would share more in common with one another the dominating alleles in playing a role in skin lightening…but as demonstrated, different set of alleles play dominating role in the lightening effect of the skin in Europeans and East Asians…
These results simultaneously and strongly suggest that Europeans and East Asians have evolved lighter skin independently and via distinct genetic mechanism, as there is an absence of any unusual pattern of diversity at SLC24A5, MATP, and TYR in East Asians
The interesting part of the study, is this about the MC1R gene about its…
The MCIR gene was the only locus examined in detail that did not show any signal of potential positive selection. Previous sequence-based studies have reached conflicting conclusions about whether or not MC1R has been subject to positive selection outside of Africa (Rana et al. 1999; Harding et al. 2000; Makova et al. 2001).
Although MC1R’s association with red hair, fair skin, freckles, and melanorma risk in European and European-derived populations primarily from the British Isles (Box et al. 1997; Smith et al. 1998a; Schioth et al. 1999; Flanagan et al. 2000; Bastiaens et al. 2001) clearly demonstrates the important regional role that it plays in pigmentation, MC1R may have (with some exceptions [John et al. 2003; Nakayama et al. 2006]) little effect on variation outside of Europe (Myles et al. 2006). Consequently, no signal will be detected using our approaches.
Although the 2 SNPs that we typed in MC1R are not strongly associated with the red hair and fair skinned phenotype for which MC1R is so well known (Sturm et al. 2003), both are polymorphic in global surveys of populations (Rana et al. 1999; Harding et al. 2000). In addition, the MC1r G92A SNP may have a ”mild” effect on pigmentation phenotype (Motokawa et al. 2006). The 92*A allele at this site is known to have a lower affinity for alpha-MSH than wild-type MC1R alleles (Xu et al. 1996), which suggests that it may contribute to **normal** variation in pigmentation. However, if positive directional selection has acted on MC1R, we would expect variation at linked sites to be affected. As such, even if have not assayed the relevant SNP, we should still have observed some signal selection, especially given the small size (~3 kb) of this gene.
So polymorphisms in the MC1R gene seem to have had relatively more impact in Europeans than other populations. Perhaps this might have something to do with the effects of MCIR mutations in Europeans having an "exacerbating effect", i.e. in addition to those of other “pigmentation”-influencing alleles therein…or maybe to some degree, tenuously linked to the effects of one or the other, or a few of those lightening alleles in Europeans.
Finally, the seem to be a strong case for the ASIP and OCA2 genes in playing a role as a taleteller [by way of ‘ancestral‘ genes and their ‘derived’ counterparts ] of the derivation of non-Africans from Africans, the populations wherein polymorphisms at these loci could well have played a role in skin tone variation to some degree or another…
The pattern of diversity at ASIP 8818*G allele (the ancestral allele associated with darker pigmentation) indicates a role primarily in African/non divergence (sub-Saharan African frequency; 66%, all other populations; 14%) rather than between darkly and lightly pigmented populations. At OCA2 355, the derived allele (linked with lighter pigmentation) occurs at its highest frequencies across Europe and Asia, but is also relatively common among Native American populations (18-34%) and is present at [b]much lower frequencies (0-10%) among Bantu-speaking African groups. In contrast, the ancestral allele associated with **dark** pigmentation has a shared **high frequency** in sub-Saharan African and Island Melanesians...
Observed patterns of global skin pigmentation diversity and their correlation with environmental UV exposure suggest an adaptive response. Although we cannot rule out a role for sexual selection, our results support multiple genetic mechanisms for evolution of skin color. We provide evidence that at least 2 genes, ASIP and OCA2, probably played a shared role in shaping light and dark pigmentation across the globe.
Aside from non-sequitur about the need for “uniformity” in dark hue in ancestral humans, considering that not even a single immediate family or household will necessarily pass for such a ridiculous test, all in all, Kittles et al.’s analysis lend strong support to the claims made by the likes of Jablonski, about dark skin being the original or default state of Homo Sapien Sapiens!
Referenced source: Genetic Evidence for the Convergent Evolution of Light Skin in Europeans and East Asians, by Rick Kittles et al. , 2006.
Right Wally? Posted by Mystery Solver (Member # 9033) on :
quote:Originally posted by rasol:
quote:Originally posted by Dunkin-Man: Hey Y'all
Long time ghost and finally a poster. I've been reading a lot of the post concerning the indeginous nature of Berbers in particular the Riffian and Kabyle Berbers aka the "White Berbers" and noticed that posters haven't addressed an important factor in genetics and geography. North Africa actually has very cold regions and in the Atlas Mountans which are the ancestral home of the berber populations temperatures can drop below zero.
Temperature per se has no bearing on skin color.
Skin color is a response to UV radiation. Even the Altas Mountains have relatively high levels of UV, compared to Northern Eurasia.
Undoubtedly, this too has also been dealt with time and again; for example, when the following question was asked…
Originally posted by al Takruri:
Why doesn't relatively lighter skin not fit North Africa, particularly the littoral where the average monthly temperatures are in some places LOWER than the monthly average for the South Europe littoral?
The response was...
Depends on how light "relatively lighter skin" is supposed to be, as it pertains to climate in North Africa.
Exposure to UV solar radiation is an instrumental determining factor in melanin synthesis regulation. UV radiation intensity varies across latitudes...
This map is provided courtesy of the Socioeconomic Data and Applications Center (SEDAC).The Center for International Earth Science Information Network (CIESIN) at Columbia University has been designated by NASA to operate and maintain SEDAC.
Data Description: This map represents local noon near-real time estimates of the UV Index (UVI) using total column ozone abundances measured by NASA's Total Ozone Mapping Spectrometer (TOMS) carried by the Earth Probe satellite. Cloud cover is not incorporated.
^Speaking of which, I see no reason why this particular Wiki piece cannot be deemed reasonable, given that this is info generally accessible in high school level physics...
On Earth, solar radiation is obvious as daylight when the sun is above the horizon. This is during daytime, and also in summer near the poles at night, but not at all in winter near the poles. When the direct radiation is not blocked by clouds, it is experienced as sunshine, a combination of bright yellow light (sunlight in the strict sense) and heat. The heat on the body, on objects, etc., that is directly produced by the radiation should be distinguished from the increase in air temperature.
The amount of radiation intercepted by a planetary body varies as the square of the distance between the star and the planet. The Earth's orbit and obliquity change with time, sometimes achieving a nearly perfect circle, and at other times stretching out to an eccentricity of 5%. The total insolation remains almost constant but the seasonal and latitudinal distribution and intensity of solar radiation received at the Earth's surface also varies (for example see a graph). For example, at latitudes of 65 degrees the change in solar energy in summer & winter can vary by more than 25% as a result of the Earth's orbital variation. Because changes in winter and summer tend to offset, the change in the annual average insolation at any given location is near zero, but the redistribution of energy between summer and winter does strongly affect the intensity of seasonal cycles. Such changes associated with the redistribution of solar energy are considered a likely cause for the coming and going of recent ice ages (see: Milankovitch cycles).
And what skin tones might look like based on "prediction" of skin melanin synthesis in response to UV solar radiation. - Jablonski et al.’s prediction of skin color distribution, as a function of UV radiation intensity [to be viewed with caution of course]:
That is a plausible explanation but I would phrase it differently. In another thread,I stated that the group known as Kabyyle, separated from the main group (OR they could be the main group, and others separated from them) BUT the process of isolation, with the Atlas serving as a natural barrier allowed them to develop (separeted from the founder gene OR vice versa). I say founder genetic effect because U6 has been found in low frequency in West Africa) and a main question should be "Which U5/U6 complex is older-The West African or Kabyle??
Form the link "When did whites enter the middle east?" is a little mixing apples and olives because it was the Fertile Crescent that served as founder effect for Europe proper meaning the "father/mother" (Fertile Crescent) provided the child that became Europe!
Posted by Dunkin-Man (Member # 13706) on :
quote:Originally posted by Dunkin-Man: Hey Y'all
Long time ghost and finally a poster. I've been reading a lot of the post concerning the indeginous nature of Berbers in particular the Riffian and Kabyle Berbers aka the "White Berbers" and noticed that posters haven't addressed an important factor in genetics and geography. North Africa actually has very cold regions and in the Atlas Mountans which are the ancestral home of the berber populations temperatures can drop below zero. I believe (and please forgive me not for more soundly verifying this first) that it takes over 10 or more generations for the climate of a place to affect the skin tone complexion of human beings. With this as a factor and also considering East African Phenotypical factors isn't it quite possible that the white berber appearance is one that is as just likely a result of them living in one of the coldest region of africa vs. Foreign admixture or a combination of the two factors ???
White skin is not an adaptation to cold. It is an adaptation to the lack of sunshine and its effects on the amount and synthesis of vitamin D. In any case, it takes a lot more than 10 generations for a genetic mutation to spread to a whole breeding population. Thirdly, just exposure to a particular environmental condition is not sufficient, a genetic mutation that promotes greater reproductive success in this particular environment is a necessary component.
Hi Thanks for getting back to my post. thanks for pointing out my mistake in my sentence. You are right white skin is not an adaptation to the cold. But also white skin is more advantageous in a cold climate especially when the correlation between vitamin d absorption and sun exposure is taken into account. next time I am at my work computer I will send you a couple of links which discuss the higher frequency of rickets and seasonal depression among people with meloderm skin vs. lycoderm skin but for now here is one such article. http://pn.psychiatryonline.org/cgi/content/full/39/14/31
Once again thank you for your post and I am learning alot from this exchange
Posted by rasol (Member # 4592) on :
quote:But also white skin is more advantageous in a cold climate especially when the correlation between vitamin d absorption and sun exposure is taken into account.
Again, this is technically not correct.
Vitaminn d absorption via UV exposure is distinct from temperature.
White skin offers no advantage to cold temperature.
Posted by Dunkin-Man (Member # 13706) on :
Doug M Member Member # 7650
Member Rated: 4 Icon 1 posted 20 June, 2007 08:44 PM Profile for Doug M Send New Private Message Edit/Delete Post Reply With Quote
quote:Originally posted by Dunkin-Man: Hey Y'all
Long time ghost and finally a poster. I've been reading a lot of the post concerning the indeginous nature of Berbers in particular the Riffian and Kabyle Berbers aka the "White Berbers" and noticed that posters haven't addressed an important factor in genetics and geography. North Africa actually has very cold regions and in the Atlas Mountans which are the ancestral home of the berber populations temperatures can drop below zero. I believe (and please forgive me not for more soundly verifying this first) that it takes over 10 or more generations for the climate of a place to affect the skin tone complexion of human beings. With this as a factor and also considering East African Phenotypical factors isn't it quite possible that the white berber appearance is one that is as just likely a result of them living in one of the coldest region of africa vs. Foreign admixture or a combination of the two factors ???
I think you are missing the crux of the argument.
There are many misconceptions about Berber speakers that can be summarized as follows:
Hey Doug M;
Thanks for replying to my argument and while I agree with certain points and have to find out more information about others let me reply to what I can
1) Berber is a language not an ethnic group or single phenotype. { While I agree that Berber is not a single phenotype the modern usage (and perhaps even the ancient usage of the term, have to check the back archives for the information on that one.) was used to refer to a ethnic group as well as speakers of a certain language. In the same way that we can talk of Mande culture/languages (which can range from the Bamana to the Mandingo and other groups) or Latin Culture/Languages (French, Italian Spanish Portuguese etc) we can talk of "Berbers" being a ethnic group.
2) Different populations with different phenotypes and ethnicities speak the Berber language. agreed
3) All Berber speakers are not white. All Berber speakers are not black either. I agree with this statement I thought that I made this clear in my initial post if I didn't I apologize its my first time posting and if I do/did not make my self clear please ask me to explain.
4) The ancestral homeland of all Berber speakers is not the Atlas Mountains.
[/B] Agreed like all Semetic speakers they originate in East Africa. However for many 1000 of years, probably much longer various Berber populations (Rifs, Kabyles, etc )have been associated with the Atlas Mountains. My point was that living in the coldest region of Africa along with foreign admixture may account for some of the lighter appearance among certain Berber populations. [/B]
5) The Berber language originated in East Africa and the populations of the Sahara. Agreed
6) The populations of East Africa and the Sahara are ANCESTRAL to North African populations.
Agreed
7) Historically MOST Berber speakers lived in the Sahara. Some moved to the coast and stuck to the lush OASES and VALLEYS to cultivate crops when the Sahara dried up. Not sure about this one being truthful or untruthful with your agreement I would like to post this to a forum which discusses Berber History or send a email to a Professor who knows the topic more definitively so that we may both get a scholarly and sourced response to this statement.
8) These Berber speakers did not move to the Mountains until the invasions of the Muslims DROVE them there.
see statement above.
9) Some Berber speakers have more foreign ancestry than others. Agreed as well. However some Africans/Asians have more foreign ancestry than others as well. I am not sure if you are one of the folks who has done this and if you're not please take no offence, But sometimes it seems like various posters make a concerted effort to deny the Africanness of the various Berber groups who don't past their reverse model of the paper bag test.
10) There are a variety of types of Berber speakers all of whom are connected by being Berber speakers and sharing a African cultural base, but who vary across time and space based on history and population movements.
Agreed.
Thanks for replying to my post hope to learn more from this discussion.
Posted by rasol (Member # 4592) on :
quote: we can talk of "Berbers" being a ethnic group.
Not a single ethnic group no. I know of no one who claims that the Siwa, Kabyle, Taureg, Souss, Harratin, etc.. all belong to the same ethnic group.
Do you?
Posted by Dunkin-Man (Member # 13706) on :
quote:Originally posted by rasol:
quote:But also white skin is more advantageous in a cold climate especially when the correlation between vitamin d absorption and sun exposure is taken into account.
Again, this is technically not correct.
Vitaminn d absorption via UV exposure is distinct from temperature.
White skin offers no advantage to cold temperature.
You're right Rasol it is technically not correct. Maybe if I was typing this on less than 3 hours of sleep I wouldn't keep wording the same mistake. That being said their is a corellation between UV radition, lower temperature and skin color.
Sorry if my language seemed to imply more cause and effect than correlation which is what I intended. One of the exceptions to the rule are the Inuit who its been hypothosiezed due to their Vitamin D rich diet kept a fairly dark complexion. Not sure how the diet of the Kabyle's and other "White" Berber groups influenced their evolution but I will try and do some research on diet and evolution before I speak on the matter more. But I do believe my theory that the folks from the coolest temperature region of Africa would share a similar appearance to those closest to them in terms of climate (Southern Europeans) plus admixture would result in the "white" berber look and can't be dismissed offhandedly as the result of Vandal and European migration/Invasion. Posted by Dunkin-Man (Member # 13706) on :
rasol Member Member # 4592
Icon 1 posted 21 June, 2007 05:48 PM Profile for rasol Edit/Delete Post Reply With Quote
quote: we can talk of "Berbers" being a ethnic group.
Not a single ethnic group no. I know of no one who claims that the Siwa, Kabyle, Taureg, Souss, Harratin, etc.. all belong to the same ethnic group.
Do you?
[B] Yes. The person making the claim is me based on the definition of the term ethnic group. A Ethnic group is defined as a group of people related by ancestry, language and customs.
Now mind, I am not saying that there are not differences between these Siwas, and Haratins and Mozabites and Kabyles but they can all be referred to as a singular ethnic group because of the linguistic ancestral and cultural connections between these groups.
In much the same way the term Latino is used in America to refer to both a black cuban immigrant, a Mexican of primarily native descent etc, because despite the differences their are also bonds of culture and language between these groups.
Despite different appearances it cannot be denied that Haratin, Kabyles and other Berber groups share enough to be refered to as a ethnic group
Posted by Mystery Solver (Member # 9033) on :
quote:Originally posted by Dunkin-Man:
But I do believe my theory that the folks from the coolest temperature region of Africa would share a similar appearance to those closest to them in terms of climate (Southern Europeans)plus admixture would result in the "white" berber look and can't be dismissed offhandedly as the result of Vandal and European migration/Invasion.
Again, temperature has nothing to do with the hue of lighter-toned Tamazight groups of coastal North Africa. Not all of them are 'tawny' in appearance either. Gene flow is the most likely reason for this variation in coastal Tamazight groups. An UV radiation map and those in the link were provided to demonstrate that North Africa is still exposed to a lot more UV radiation than northern Eurasia.
Skin pigmentation markers have also been provided to demonstrate this. See post above.
Coastal Tamazight groups have higher incidences of West Eurasian markers [largely maternal]. Given this, not to mention relative proximity, it comes as no mistery as to how coastal North Tamazight groups [which are by no means uniform] who derive from much more pigmented Tamazight groups, got their relatively distinguished hue from the rest of the continent over the course of history.
Posted by Mystery Solver (Member # 9033) on :
quote:Originally posted by Dunkin-Man:
Yes. The person making the claim is me based on the definition of the term ethnic group. A Ethnic group is defined as a group of people related by ancestry, language and customs.
Now mind, I am not saying that there are not differences between these Siwas, and Haratins and Mozabites and Kabyles but they can all be referred to as a singular ethnic group because of the linguistic ancestral and cultural connections between these groups.
In much the same way the term Latino is used in America to refer to both a black cuban immigrant, a Mexican of primarily native descent etc, because despite the differences their are also bonds of culture and language between these groups.
Despite different appearances it cannot be denied that Haratin, Kabyles and other Berber groups share enough to be refered to as a ethnic group
Yes, Tamazight groups share some cultural traits and derive their languages from common origins, but there is no solid political cohesion between the sub-groups, at least not yet. 'Latino' is just as much a lingual reference as 'Berber' is.
Posted by rasol (Member # 4592) on :
quote:Originally posted by Dunkin-Man: The person making the claim is me based on the definition of the term ethnic group.
Despite different appearances it cannot be denied that Haratin, Kabyles and other Berber groups share enough to be refered to as a ethnic group
i'm fascinated by this, because I am familiar with Amazigh nationalism and it is characteristically highly devisive on this point.
Some go to the extreme of flat out denying that dark skinned Berber are 'real' Berber:
^ But you are saying all Berber are 'one' ethnically? Correct?
Posted by Doug M (Member # 7650) on :
^The funniest part is when they admit the Haratin are the original people, but somehow not "Berber" meaning not TRUE North Africans...... doh!
Posted by Dunkin-Man (Member # 13706) on :
[B] quote:Originally posted by Dunkin-Man: The person making the claim is me based on the definition of the term ethnic group.
Despite different appearances it cannot be denied that Haratin, Kabyles and other Berber groups share enough to be refered to as a ethnic group
i'm fascinated by this, because I am familiar with Amazigh nationalism and it is characteristically highly devisive on this point.
Some go to the extreme of flat out denying that dark skinned Berber are 'real' Berber:
-
^ But you are saying all Berber are 'one' ethnically? Correct? Posts: 10638 | Registered: Jun 2004 |
^The funniest part is when they admit the Haratin are the original people, but somehow not "Berber" meaning not TRUE North Africans...... doh! [B]
You guys bring up a good point that skin color is a issue among Berbers. I do not believe however that this dimishes the linguistic or cultural ties. Some Amazigh Nationalist will try and act as if black berbers don't exist however facts is facts and no amount of wishing or rhetoric can diminish the ancestral, cultural and linguistic connections which still make them a ethnic group.
In all fairness to the Amazigh nationalist (and this is not a validation of the berber =white mentality.) colorism is a major problem in multi hued ethnic groups.
For e.g. Among Afro Americans the term I used in a earlier post "The paper bag test." is a result of I believe the same mindset that informs the Amazigh nationalist you refer to. In Latin American Countries their is usually a hierachy with white being placed on the top and people of African and Native Descent at the bottom. In India the standard for Bollywood movies is always light and fair despite having a population which can in various instances be as dark if not darker than your stereotypical West African. This problem doesn't make any of these groups less ancestrally, culturally or linguistically related it means that they have problems much as in the case of the Amazigh.
Posted by Dunkin-Man (Member # 13706) on :
quote:Originally posted by Dunkin-Man: The person making the claim is me based on the definition of the term ethnic group.
Despite different appearances it cannot be denied that Haratin, Kabyles and other Berber groups share enough to be refered to as a ethnic group
i'm fascinated by this, because I am familiar with Amazigh nationalism and it is characteristically highly devisive on this point.
Some go to the extreme of flat out denying that dark skinned Berber are 'real' Berber:
-
^ But you are saying all Berber are 'one' ethnically? Correct? Posts: 10638 | Registered: Jun 2004 |
^The funniest part is when they admit the Haratin are the original people, but somehow not "Berber" meaning not TRUE North Africans...... doh!
You guys bring up a good point that skin color is a issue among Berbers. I do not believe however that this dimishes the linguistic or cultural ties. Some Amazigh Nationalist will try and act as if black berbers don't exist however facts is facts and no amount of wishing or rhetoric can diminish the ancestral, cultural and linguistic connections which still make them a ethnic group.
In all fairness to the Amazigh nationalist (and this is not a validation of the berber =white mentality.) colorism is a major problem in multi hued ethnic groups.
For e.g. Among Afro Americans the term I used in a earlier post "The paper bag test." is a result of I believe the same mindset that informs the Amazigh nationalist you refer to. In Latin American Countries their is usually a hierachy with white being placed on the top and people of African and Native Descent at the bottom. In India the standard for Bollywood movies is always light and fair despite having a population which can in various instances be as dark if not darker than your stereotypical West African. This problem doesn't make any of these groups less ancestrally, culturally or linguistically related it means that they have problems much as in the case of the Amazigh.
Posted by rasol (Member # 4592) on :
quote:You guys bring up a good point that skin color is a issue among Berbers. I do not believe however that this dimishes the linguistic or cultural ties.
I agree with you. And I encourage effort to study and denote common cultural ties amongst Berber peoples regardless of superflous physical distinctions.
Posted by Tyrannosaurus (Member # 3735) on :
^ Is it just me or does that band of high UV move up and down?
Here, more UV is on the Southern Hemisphere:
But here, there is more UV on the Northern Hemisphere (and southern Africa has a similar UV level to Europe):
Is this a result of the planet's tilt changing throughout the year?
Posted by Djehuti (Member # 6698) on :
^ I think it has more to do with the earth's orbit around the sun as well as its tilt.
Either way, skin color corresponds to UV rays present and NOT temperature.
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