Post by djoser-xyyman on Nov 7, 2014 11:27:53 GMT -5
This paper is a little dated, not in terms of date, but in terms of what we now know in Nov2014. The in situ(actual testing of humans remains) has made this hypthesis to say the least …null and void. This is a good example on why you can not believe all the BS that comes out of Europeans mouths. I wish they would stick to the FACTS(sgt Friday). If Beyoku is reading this there is a sections he may find interesting. Ie the timing of the exit of AMH OOA. Some cited here authors suggest as late as 25,000ya!!!.
So, I am not the only one. The genetic data and geographic patterns suggest such a late migration, OOA exit. I have speculated about that.
The other thing that stands out is the suggestion that AMH left Africa with the ability to develop white skin. . And it was later waves of Africans that introduce light skin to Europe. The La Brana and other black ancient Europeans have confirmed that. Amazing isn’t it? If the main stream media get wind of this…well…truth may indeed be stranger than fiction.
Keep in mind…lightening is essentially the “reduction “ in the production of melanin. In other words if SSA and other blacks bodies stop produce melanin they will be …”white”. Melanin production is Nature’s way of protecting the skin from high intensity harmful UV.
----------------------------
The Timing of Pigmentation Lightening in Europeans(2012)
Sandra Beleza,*,…Mark D. Shriver,
Recently, several genes affecting melanin production and melanin function have been shown to influence normal pigmentation variation in human populations by using association approaches and/or direct functional assays (reviewed in Parra 2007; Sturm 2009; Rees and Harding 2012).
Some genes, such as KITLG, have derived alleles (associated with lighter pigmentation) that reach high frequencies both in European and East Asian populations and likely began to be selected in a proto Eurasian population (Lao et al. 2007; Williamson et al. 2007; Pickrell et al. 2009). Other genes have derived alleles with a distribution primarily restricted to either Europe (SLC24A5, SLC45A2 and TYRP1) or East Asia (DCT and ATRN), suggesting that different genes are responsible for the reduction of melanin content in Europeans and East Asians (McEvoy et al. 2006; Lao et al. 2007; Myles et al. 2007; Norton et al. 2007; Pickrell et al. 2009). Additional evidence for convergent adaptation is provided by genes such as OCA2,
For example, some distributions of derived alleles in European populations are consistent with both an early sweep, starting soon after the migration of anatomically modern humans into Europe, and with more recent dates occurring long after the arrival of modern human populations to the continent (Cavalli-Sforza et al. 1994; Norton and Hammer 2008). Similarly, selective sweeps at genes such as KITLG may have occurred immediately after the out-of-Africa migration or only shortly
differences between European and West African populations (Lamason et al. 2005; Miller et al. 2007; Norton et al. 2007), and TYRP1, which is associated with variation in iris pigmentation and hair color within Europe (Frudakis et al. 2003; Sulem et al. 2008; Liu et al. 2010). The modes of our age estimates indicate that the derived lineage shared by Europeans and East Asians at KITLG started to rise
Results
The derived alleles SLC24A5*A and SLC45A2*G both have frequencies higher than 90% in Europeans but are much more rare or absent in Africans and East Asians. The TYRP1*G allele, which is also rare among Africans and East Asians, reaches an intermediate frequency of 60% in Europeans. At the rs642742 SNP, the frequency of the KITLG*G derived allele in Africans is 7%, in contrast to the high frequencies found in Europeans and East Asians (_80%).
Our results based on the KITLG gene suggest that the initial stages of European skin lightening occurred in a proto- Eurasian population, approximately 30,000 years ago, after the out-of-Africa migration _60,000–70,000 years ago
[b****]Recent estimates ****based on genome-wide patterns of variation[/b] have suggested that the European and East Asian divergence might have occurred as late as _25,000 years ago (Keinan et al. 2007; Gutenkunst et al. 2009; Laval et al. 2010; Rasmussen et al. 2011), implying that the colonization of Europe could have involved several migration movements at different ages (Laval et al. 2010). Our estimates for the onset of selection at KITLG are consistent with these findings, although more ancient dates (>40,000 years) cannot be excluded, due to uncertainty of age estimates. In any case, both the modal age estimates (table 3) and the extensive sharing of derived lineages between European and East Asian populations (supplementary fig. S3, Supplementary Material online) suggest that the onset of the KITLG sweep occurred before the divergence of the ancestors of present-day Europeans and East Asians, well after modern humans left Africa.
Our estimates additionally show that the onset of selective sweeps at SLC24A5, SLC45A2, and TYRP1, the three genes in which the geographic distribution of the polymorphisms is primarily restricted to European populations, was much more ***recent**** than at KITLG and remarkably compressed within the last 11,000–19,000 years (table 3), suggesting that lighter pigmentation alleles at these three loci began to rise in frequency only in the latest phases of the Upper Paleolithic, encompassing the Solutrean and the Magdalenian cultures. One prior study has similarly suggested that the selective sweep at the SLC45A2 OCCURRED LONG AFTER the arrival of anatomically modern humans in Europe (Soejima et al. 2006).
Although the timing of the selective sweep(s) is clear from these analyses, ****IT IS LESS CLEAR WHETHER THE GENETIC VARIANTS UNDERLYING THIS ADAPTIVE RESPONSE ORIGINATED IN EURASIA OR WERE ALREADY PRESENT IN AFRICA BEFORE THE ANCESTORS OF CONTEMPORARY NON-AFRICANS LEFT THE CONTINENT. *****.
Xyyman comment: Now(La Brana and others) we know this statement is true
Previous studies using several population samples from different continents have shown that, unlike SLC45A2, derived alleles at SLC24A5, TYRP1, and KITLG are present at low frequencies in some sub-Saharan populations (table 1, see also Yuasa et al. 2006; Frazer et al. 2007; Norton et al. 2007; Soejima and Koda 2007; Coop et al. 2009; Pickrell et al. 2009). We see three possible explanations for these patterns: 1) the derived alleles arose in Europe (for SLC24A5 and TYRP1) or in the ancestral Eurasian population (for KITLG) where they increased in frequency and were introduced later into Africa by gene flow, 2) the derived alleles arose in Africa, where they remain at low frequencies and spread out of Africa with the early migrations of modern humans. These alleles were then lost from the ancestral gene pools of East Asians (except for KITLG) and ultimately increased in frequency in the ancestors of Europeans, and 3) the African and European alleles had independent mutational origins and are homoplastic, which is an unlikely scenario. It would be necessary to carry out a more exhaustive study of the diversity of these loci, and particularly, the pattern of intra-allelic variation for the derived alleles in African and Eurasian populations, to clarify these issues..
Xyyman comment: This was done recently in the La Brana paper. The genetic variability at several of the pigmentation loci are highest in South Saharan Africans!!!! Meaning Europeans are NOT the source of light skin. Who would of guessed it.
So, I am not the only one. The genetic data and geographic patterns suggest such a late migration, OOA exit. I have speculated about that.
The other thing that stands out is the suggestion that AMH left Africa with the ability to develop white skin. . And it was later waves of Africans that introduce light skin to Europe. The La Brana and other black ancient Europeans have confirmed that. Amazing isn’t it? If the main stream media get wind of this…well…truth may indeed be stranger than fiction.
Keep in mind…lightening is essentially the “reduction “ in the production of melanin. In other words if SSA and other blacks bodies stop produce melanin they will be …”white”. Melanin production is Nature’s way of protecting the skin from high intensity harmful UV.
----------------------------
The Timing of Pigmentation Lightening in Europeans(2012)
Sandra Beleza,*,…Mark D. Shriver,
Recently, several genes affecting melanin production and melanin function have been shown to influence normal pigmentation variation in human populations by using association approaches and/or direct functional assays (reviewed in Parra 2007; Sturm 2009; Rees and Harding 2012).
Some genes, such as KITLG, have derived alleles (associated with lighter pigmentation) that reach high frequencies both in European and East Asian populations and likely began to be selected in a proto Eurasian population (Lao et al. 2007; Williamson et al. 2007; Pickrell et al. 2009). Other genes have derived alleles with a distribution primarily restricted to either Europe (SLC24A5, SLC45A2 and TYRP1) or East Asia (DCT and ATRN), suggesting that different genes are responsible for the reduction of melanin content in Europeans and East Asians (McEvoy et al. 2006; Lao et al. 2007; Myles et al. 2007; Norton et al. 2007; Pickrell et al. 2009). Additional evidence for convergent adaptation is provided by genes such as OCA2,
For example, some distributions of derived alleles in European populations are consistent with both an early sweep, starting soon after the migration of anatomically modern humans into Europe, and with more recent dates occurring long after the arrival of modern human populations to the continent (Cavalli-Sforza et al. 1994; Norton and Hammer 2008). Similarly, selective sweeps at genes such as KITLG may have occurred immediately after the out-of-Africa migration or only shortly
differences between European and West African populations (Lamason et al. 2005; Miller et al. 2007; Norton et al. 2007), and TYRP1, which is associated with variation in iris pigmentation and hair color within Europe (Frudakis et al. 2003; Sulem et al. 2008; Liu et al. 2010). The modes of our age estimates indicate that the derived lineage shared by Europeans and East Asians at KITLG started to rise
Results
The derived alleles SLC24A5*A and SLC45A2*G both have frequencies higher than 90% in Europeans but are much more rare or absent in Africans and East Asians. The TYRP1*G allele, which is also rare among Africans and East Asians, reaches an intermediate frequency of 60% in Europeans. At the rs642742 SNP, the frequency of the KITLG*G derived allele in Africans is 7%, in contrast to the high frequencies found in Europeans and East Asians (_80%).
Our results based on the KITLG gene suggest that the initial stages of European skin lightening occurred in a proto- Eurasian population, approximately 30,000 years ago, after the out-of-Africa migration _60,000–70,000 years ago
[b****]Recent estimates ****based on genome-wide patterns of variation[/b] have suggested that the European and East Asian divergence might have occurred as late as _25,000 years ago (Keinan et al. 2007; Gutenkunst et al. 2009; Laval et al. 2010; Rasmussen et al. 2011), implying that the colonization of Europe could have involved several migration movements at different ages (Laval et al. 2010). Our estimates for the onset of selection at KITLG are consistent with these findings, although more ancient dates (>40,000 years) cannot be excluded, due to uncertainty of age estimates. In any case, both the modal age estimates (table 3) and the extensive sharing of derived lineages between European and East Asian populations (supplementary fig. S3, Supplementary Material online) suggest that the onset of the KITLG sweep occurred before the divergence of the ancestors of present-day Europeans and East Asians, well after modern humans left Africa.
Our estimates additionally show that the onset of selective sweeps at SLC24A5, SLC45A2, and TYRP1, the three genes in which the geographic distribution of the polymorphisms is primarily restricted to European populations, was much more ***recent**** than at KITLG and remarkably compressed within the last 11,000–19,000 years (table 3), suggesting that lighter pigmentation alleles at these three loci began to rise in frequency only in the latest phases of the Upper Paleolithic, encompassing the Solutrean and the Magdalenian cultures. One prior study has similarly suggested that the selective sweep at the SLC45A2 OCCURRED LONG AFTER the arrival of anatomically modern humans in Europe (Soejima et al. 2006).
Although the timing of the selective sweep(s) is clear from these analyses, ****IT IS LESS CLEAR WHETHER THE GENETIC VARIANTS UNDERLYING THIS ADAPTIVE RESPONSE ORIGINATED IN EURASIA OR WERE ALREADY PRESENT IN AFRICA BEFORE THE ANCESTORS OF CONTEMPORARY NON-AFRICANS LEFT THE CONTINENT. *****.
Xyyman comment: Now(La Brana and others) we know this statement is true
Previous studies using several population samples from different continents have shown that, unlike SLC45A2, derived alleles at SLC24A5, TYRP1, and KITLG are present at low frequencies in some sub-Saharan populations (table 1, see also Yuasa et al. 2006; Frazer et al. 2007; Norton et al. 2007; Soejima and Koda 2007; Coop et al. 2009; Pickrell et al. 2009). We see three possible explanations for these patterns: 1) the derived alleles arose in Europe (for SLC24A5 and TYRP1) or in the ancestral Eurasian population (for KITLG) where they increased in frequency and were introduced later into Africa by gene flow, 2) the derived alleles arose in Africa, where they remain at low frequencies and spread out of Africa with the early migrations of modern humans. These alleles were then lost from the ancestral gene pools of East Asians (except for KITLG) and ultimately increased in frequency in the ancestors of Europeans, and 3) the African and European alleles had independent mutational origins and are homoplastic, which is an unlikely scenario. It would be necessary to carry out a more exhaustive study of the diversity of these loci, and particularly, the pattern of intra-allelic variation for the derived alleles in African and Eurasian populations, to clarify these issues..
Xyyman comment: This was done recently in the La Brana paper. The genetic variability at several of the pigmentation loci are highest in South Saharan Africans!!!! Meaning Europeans are NOT the source of light skin. Who would of guessed it.