Talk:Sodium/potassium/calcium exchanger 5

When?

Is there any information on when did the mutation that originated the threonine allele happen?

As it says in the article, "5,300 to 12,000 years ago" Pstanton 07:16, 10 January 2009 (UTC) —Preceding unsigned comment added by Pstanton (talk • contribs)

the article states 5300 to 6000 years ago Mnlk 01:23, 16 February 2011 (UTC)

Mnlk 01:23, 16 February 2011 (UTC)

Gene and protein names

According to Q71RS6, "solute carrier family 24 member 5" is an accepted alternated name for the "sodium/potassium/calcium exchanger 5" (NCKX5) protein. Of course, "solute carrier family 24, member 5" is also the approved HUGO gene name (see SLC24A5). So the protein and gene names overlap. As discussed here and here, we have tried to make clear in the lead that the scope of Gene Wiki articles encompasses (1) both the gene and the protein encoded by that gene and (2) not only the human gene/protein, but also orthologs that exist in other species. The wording that was reached through consensus is perhaps a little awkward, but it is both accurate and concise:

• <recommended UniProt name> is a protein that in humans is encoded by the <approved HUGO gene symbol> gene.

The "that" in the above sentence is non-limiting implying that the protein (and gene) exists in other species besides human. Boghog (talk) 11:15, 27 October 2010 (UTC)

Problematic Text

"The SLC24A5 gene's derived threonine or Ala111Thr allele (rs1426654[5]) has been shown to be a major factor in the light skin tone of Europeans compared to Africans,"

First, why compared to Africans? The sentence would be more accurate if it read: "a major factor in the light skin tone of Europeans and South Asians", which is true. Which brings me to point two:

" and is believed to represent as much as 25–40% of the average skin tone difference between Europeans and West Africans." Again, why compare Europeans to West Africans? This is to revive the 'True Negro' hypothesis of human evolution that was the mainstay of biological determinism. There is nothing peculiarly unique about West African dna. Most West Africans characteristically have the East African haplogroup E1b1a. Female mtdna in West Africa is no older than in Southern Africa or the Nile Valley. So why compare Europe and West Africans? MrSativa (talk) 00:05, 8 January 2017 (UTC)

It's compared to Africans because the information comes from a reliable source, not our own imaginations, and that source compares Europeans and Africans. Here is the full text: http://biolog-e.ls.biu.ac.il/faculty/wides/80-440/skinpigmentation1782.pdf, here is a quote: "our results suggest that SLC24A5 explains between 25 and 38% of the European-African difference in skin melanin index". The source doesn't specify "West African" so I've changed it to "sub-Saharan African"

You should note that the derived (ie light-skin) variant of SLC24A5 exists in high frequencies in South Asians, so comparing to them would be a bad idea for this gene. A study of European vs South Asian skin colour found a mutation in the similar-sounding, but different, SLC45A2 gene that is the primary factor in European/South Asian differences. See http://link.springer.com/article/10.1007%2Fs00414-006-0112-z, or the Human skin color wikipage.

Tobus (talk) 01:45, 8 January 2017 (UTC)

"The source doesn't specify "West African" so I've changed it to "sub-Saharan African". Obviously West African and "sub-Saharan African" are not the same, unless you think that the sub-Saharan population comes from West Africa. SLC24A5 is quite prevalent among East Africans, nor is it completely absent from West Africa. So which 'sub-Saharan Africa' are you talking about - unless of course you think that Ethiopia, Somalia, Sudan are not 'sub-Saharan'. MrSativa (talk) 23:29, 10 January 2017 (UTC)

I used "sub-Saharan African" because you objected to "West African" and I'm pretty sure the source wasn't talking about North Africans when referring to "the European-African difference in skin melanin". You really should read the paper, particularly the "Role of SLC24A5 in human pigmentation" section. They refer to the HapMap database for allele frequencies, which at the time had Yoruba from Nigeria as the African samples. For testing the correlation of the allele to skin pigmentation they used "samples from two recently admixed populations, an African-American and an African-Caribbean population", and when estimating the size of the effect they based their calculations on "the average pigmentation difference between European-Americans and African-Americans". The African slave trade to the Americas took people mainly from West Africa, which is possibly why the original editor specified "West African". We could just say "African" in general like they do in the source, but I think a distinction at least between North and sub-Saharan is important in this case, as North Africans have a very different genetic ancestry and phenotype, and weren't included in the study. Tobus (talk) 00:23, 11 January 2017 (UTC)

The problem with both 'West African' and 'Sub-Saharan' is that neither of them are the darkest skinned people in Africa. People in the Nile Valley - Sudan - are. And that gets to the core of the question: other than 'West African' enforcing Seligman's idea of the True Negro and the West African origin of black people. And that's just not the genetic understanding of history that we have today. The most widespread haplogroup in West Africa, and among African Americans, E1b1a, is an East African haplogroup when you consider the high concentration of E1b1b in East Africa, and the fact that older E haplogroups are also found there. So why compare Europeans today with Africans today? — Preceding unsigned comment added by 83.84.100.133 (talk) 17:32, 27 September 2018 (UTC)

No offense, but we're describing the results of a scientific study here - if you have a problem with comparing modern Africans and Europeans you would need to take it up with the authors of the paper. Tobus (talk) 00:23, 28 September 2018 (UTC)

Frequency map

The mapped frequencies for areas in the southern Indian subcontinent appear to be not entirely representative. The derived SLC24A5 allele has been observed at frequencies of around 50% among Sinhalese and about 18% among Tamils [1] [2]. Soupforone (talk) 04:04, 2 September 2017 (UTC)

"obvious"

From the article, "Tests for this variation have obvious application to forensic science." I'm a geneticist and I find this condescending and insufficiently specified. — Preceding unsigned comment added by 24.182.18.253 (talk) 03:49, 7 April 2019 (UTC)

Removed. Boghog (talk) 04:18, 7 April 2019 (UTC)

Reinstated with more accurate and specific wording, plus sources Tobus (talk) 05:47, 7 April 2019 (UTC)

Recent?

The intro states that the SLC24A5 gene has been the subject of "recent" selection for skin color in Europe. How recent is that? The Beleza, et al, article footnote 9 indicates 11-19K years ago, for just that gene, while skin color selection has gone on much longer. I suggest putting a more concrete time period on it. I've had students who think that The Beatles are ancient history. Dynasteria (talk) 18:38, 30 May 2021 (UTC)

I've updated it with the most recent studies that suggest ongoing selection over the last 5,000 years (plus added recent information of the alleles prevalence in Khoisan people). Tobus (talk) 00:09, 31 May 2021 (UTC)

I concur. Would it be appropriate to add the time of origin? Dynasteria (talk) 08:15, 31 May 2021 (UTC)

Footnotes

The footnotes seem out of whack. I can't find 1-4 or 8 in the article itself. I'd attempt to fix it but have no idea how. Dynasteria (talk) 18:44, 30 May 2021 (UTC)

If you click the "^" or "a"/"b"/"c" etc. at the start of each reference it takes you to the place in the text where it is used. 1-4 are in the infobox on the right hand side. 8 is in the 1st sentence of the 2nd para in the lead (after "between Europeans and West Africans.") Tobus (talk) 00:13, 31 May 2021 (UTC)

Thanks. I see them now. Dynasteria (talk) 08:03, 31 May 2021 (UTC)