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Ancient west Eurasian ancestry in southern and eastern Africa 2013
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[QUOTE]Originally posted by The Explorer: [QB] Synopsis of what transpired, starting with this partial recap from page 1: [b]The easing up of skin eumelanin in San hunter-gatherers has generally been attributed to local evolution in lower UV radiation environments they frequent, as opposed to the result of gene flow[/b]. In the Ethiopian samples, on the other hand, the presence of the "derived" variant of the SLC24A5 gene was peculiar in that it was not found in tandem with other "skin-pigmentation" affiliated genes whose distribution generally paralleled that of the "derived" SLC24A5 variant, particularly in Europeans. Hence, "frequency" in itself is not a sufficient enough indicator for ascribing a single-source origin in the form of a "non-African" origin. - Extract ends From blog entry, "[i]What Ethiopian Genetic Diversity—Really—Reveals![/i]", May 15, 2013: This [SLC24A5] gene, in its derived form, which is said to be under positive selection in "lightly" pigmented populations, was [b]implicated in the San[/b], who as noted above, [b]tend to generally be isolated[/b], and [b]culturally-conservative hunter-gatherers[/b]. [b]"Derived" variants[/b] of [b]other[/b] pigmentation-associated genes were also cited, [b]with respect to the San[/b]([5]). It is [b]questionable that this gene is serving as a "non-African" marker in the San[/b]. The [b]same issue actually surfaces with regards to its presence in Ethiopian[/b] groups: Secondly: [i][b]Given that SLC24A5 is one of the most highly differentiated genes between African and European[/b] populations, we then [b]looked for other highly differentiated genes[/b] among the outlier windows, [b]but found none[/b]... To [b]further investigate the effect of admixture on the genetic landscape of skin pigmentation in Ethiopia[/b], we also [b]looked at other genes associated with pigmentation in Europe[/b]; however, [b]none were found in our outlier regions[/b].[/i] If this gene, in its "derived" form, was essentially serving as a "non-African" marker in the Ethiopians, then [b]one would expect that other "derived" skin-pigmentation markers would have been introduced along with the SLC24A5 allele[/b], by the foreign "non-African" group(s) that is supposed to have been the source. [b]Skin pigmentation is the byproduct of the consortial work of a number of distinct genes[/b], and [b]so, it's highly unlikely that a "derived" SLC24A5 allele would be introduced without other accompanying skin-pigmentation genes[/b]. No less, it's [b]highly unlikely that only the derived "SLC24A5" allele would survive[/b] from a foreign "non-African" source, [b]in a population for which the allele's presence is "potentially disadvantageous"[/b], as the authors note, on grounds of the kind of UV-radiation intensive environment they generally reside. Likewise, [b]if as the authors note[/b], the [b]presence of the derived SLC24A5 allele in Ethiopians may be attributable to "socially"-promoted selection[/b], then one would think that [b]other skin-pigmentation genes, which would have accompanied the SLC24A5 allele[/b] in an introduction by a foreign "non-African" source, [b]would have likely also survived in some capacity or another[/b], so as [b]to serve the same role that the SLC24A5 may be serving[/b]. --Extract ends As any rational person will glean from these notes, the issues raised undoubtedly emerge from a scientific and objective groundwork. - The Explorer, June 30, 2013 These notes naturally speak to the arguments put forth by Pagani et al., but they set off mindless hysteria in the fuckhead queen called 'swenet'... who starts babbling about some undefined "non-skin pigmentation" related "biological function" of the derived SLC24A5 variant supposedly introduced to Ethiopians via "gene flow"... To this, the idiot was informed that a marker serving as "gene flow" would be introduced "as is", and as such, one that is under selective pressure, will continue to have that selective attribute. From there, it boils down to whether the selective trait is advantageous or deleterious--and to what degree--to the "receiving" population, which will subsequently decide the fate of an allele. The "receiving" population doesn't get to cherry pick which trait to pick and which to discard at a conference table; that's not how nature works to swenet's dismay. Furthermore, the knucklehead doesn't understand that SLC24A5 having a "different biological function" in Ethiopians from that of an alleged external source, actually weakens the claim for "gene flow", and only reinforces the point I'm making above. My objection to the idiot's obsession over said "different biological function" that is presumably "non-skin pigmentation related", is that it is immaterial to Pagani et al.'s case, since they make no mention of such a "biological function", other than "skin pigmentation" as the phenotypic trait associated with the SLC24A5 variant. This was turned upside down by the fuckhead queen to mean, that "non-skin pigmentation" related expressions of SLC24A5 gene are "fictitious". I also clearly note in the blog passages above that: [i][b]Skin pigmentation is the byproduct of the consortial work of a number of distinct genes[/b][/i] - from the blog So, it is not unheard of for a population to have a skin pigmentation allele that resembles that of populations which are usually identified with said allele, and yet, have other skin pigmentation alleles that are different from said populations. The derived variant of SLC24A5 similar to the type present in Europe and "southwest Asia" can be present in Ethiopians, yet other alleles that typically accompany the variant in the said regions can be absent in Ethiopians. As such, even if SLC24A5 has a phenotypic trait that is generally disadvantageous in the tropics, by its lonesome, it is not going to have as profound an impact on skin pigmentation as it allegedly does in say, Europeans... which brings us to the question of why then, there seems to be indication (as shown in the Z-scores) that a derived variant is "selected for" in Ethiopians. Pagani et al., apparently working with their "gene flow" theory, posit that it could be the byproduct of "socially" channeled "selection", like say, "sexual selection". I've already laid out the coherency difficulties which inflict that [b]composite[/b] theorizing. While the "social factor" is a plausible scenario, unlike Pagani et al., I posit that the allele could have been selected initially for a different environment, on the African continent itself (the sub-tropical Sahara), in the ancestral populations of Ethiopians in question. fuckhead queen also turned upside down, my arguments to this end; instead fuckhead queen says "I" am making a case for "a selection of light skin pigmentation in the tropical environment", and asks me why "other genes" (skin pigmentation) typically found in Europe and "southwest Asia", were not found in Ethiopians. I told the fuckhead queen, it's because Ethiopians have their own skin pigmentation genes, otherwise they would be colorless. By this silly question, what the fuckhead queen was really trying to say, is that other skin pigmentation alleles vanished into extinction, while the SLC24A5 variant stayed. But the fuckhead realizes that this runs into one of the problems I already identified: that it makes no sense for SLC24A5 to stick around, given the identified (in the text) phenotypic trait associated with skin pigmentation, while other skin pigmentation alleles serving a similar purpose, simply vanished. This forced the fuckhead queen to look to some other, presumably a "non-skin pigmentation" related "biological function" of the gene, that Pagani et al.'s text makes no mention of. The fuckhead queen was thereafter called out for fictitiously ascribing said unspecified "biological function" to Pagani et al.'s text, but fuckhead queen translated this to mean, "other biological functions of SLC24A5 are fictitious". :D The fuckhead queen was even forced to refer to "eye color" as this supposed "non-skin pigmentation" related "biological function" at one point. That led to an obvious dead end, when the fuckhead queen was asked to cite Pagani et al.'s piece making a case of that nature. My theory takes into account the plausibility that the "derived" SLC24A5 variant may have been initially selected for in a different African environment, but because it merely contributed to the skin tone continuum seen in said Ethiopians, as opposed to having a decisive role, SLC24A5 variant managed to survive the UV environment of the tropics. This is how my theory takes into account, the "social factor" that Pagani et al were speaking of, in an entirely different context. You see, the ancestors of said Ethiopians living in sub-tropical African environment north of the equator may have undergone some skin pigmentation relaxation, initially as a response to the said sub-tropical environment, but not enough to have gone to the extreme relaxations seen in Europe, for instance. As such, their skin pigmentation relaxation was perhaps not extreme enough to make their survival in the tropical African environment unbearable. This will adequately account for why SlC24A5 derived variant happens to appear in Ethiopians at substantial frequencies, while other skin pigmentation alleles generally associated with Europeans do not. The fuckhead queen proceeds to ask me why there is frequency disparity between major Cushitic-Semitic Ethiopian groups and the Omotic and Nilotic Ethiopians. To it's puzzlement, the fuckhead queen was thereof informed that it must be reflective of the different bio-histories of said groups. [BTW, I give details of these distinct bio-histories in the blog entry cited] As if that was not bizarre enough, the fuckhead queen cites from a different study, that is totally irrelevant to Pagani et al.'s text or this discussion: the fuckhead queen cites from a study comparing Sri Lankans to several samples, including those from Europe. It is from here, that SLC45A2 was introduced into this discussion. The fuckhead queen's motive for this citation, was supposedly to show me that SLC24A5 was found in Sri Lankans along with SLC45A2, which must therefore mean that they only attained SLC24A5 from Europeans, and henceforth, supposedly refute what I said about the Ethiopian case, which no less, resembles nothing like the Sri Lankan case. The only [unintended] thing the Sri Lankan case managed to do, is give even more fodder to my argument, since even that study--as irrelevant as it was--showed that it was SLC45A2 rather than SLC24A5 that proved to sufficiently differentiate European samples and the Sri Lankan counterparts; SLC24A5 was relatively weak in performing that role. What this means, is that between the two skin pigmentation variants, SLC45A2 would have served better as a marker of European ancestry than would SLC24A2, if such a case were to hypothetically be entertained. Simply put, SLC24A5 has a wider distribution, and hence, more generic. Running out of ideas to con a way out of this mess of a fiasco that missy created, fuckhead queen decides to take a crack at nutty accusations about "being stumped", presumably by some "three" bulleted points. Asked for evidence, in the form of quotes, the fuckhead queen says that it is from a "non-verbal" analysis, which is beyond comical, because the only way to know anything about me, is from what I write in the thread. fuckhead queen would have to either see me to read my body language perhaps, which any sane person knows is out of the question, or have supernatural powers to read minds afar from behind a computer screen. fuckhead queen instead compares this bizarre accusation with the prospect of "knowing that I exist", but presumably me denying this. Of course, the fuckhead queen would know I exist, only because I happen to post here and elsewhere. But try telling something that very simple to princess dufus. From here, everything only becomes repetitive, as fuckhead queen tries to salvage whatever's left of that tattered ego from merciless defeat. Going in circles, with wimpy posts about how I supposedly did the fuckhead queen wrong, left something said (usually pure crap) unadressed or how I "lied" about some post or another, is what fuckhead queen usually does after humiliating defeat in every discussion. :) For the finer details, spectators need to just turn to the first page, but this sums up what happened. ;) [/QB][/QUOTE]
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