Wikipedia:Reference desk/Archives/Science/2018 September 29

= September 29 =

Are there any pathogens where the fraternal birth order effect makes a difference?
It's been established that the more older brothers a boy has, the more likely he is to be gay:

http://www.pnas.org/content/early/2017/12/05/1705895114

This fact, combined with Greg Cochran's theory about a pathogen being response for male homosexuality, makes me wonder:

Are there any pathogens where the fraternal birth order effect makes a difference? Specifically, are there any pathogens where the more older brothers a boy or man has, the more likely he is to be affected by this pathogen?

Basically, I am asking this question in order to get a rough idea of the likelihood of Greg Cochran's theory actually being correct. Also, No, I'm certainly not trolling; rather, I am trying as best as an amateur can in figuring out the truth behind this issue. Futurist110 (talk) 01:11, 29 September 2018 (UTC)


 * It doesn't sound like much of a "theory" where Cochran is concerned,
 * Can you please elaborate on this part? Futurist110 (talk) 01:30, 3 October 2018 (UTC)


 * but the association of homosexuality with a female anti-neuroligin 4 Y-linked (NLGN4Y) antibody is fascinating. This makes it sound like the antibody could be a simple case of an Rh factor like phenomenon; however, bear in mind that evolutionarily this "problem" could easily be "fixed" (women could express NLGN4Y anywhere in their bodies - big toe, salivary gland, wherever - and then it would end up being recognized as a self antigen and homosexuality would go away).  This would indicate that far from being some insoluble design issue, homosexuality has been preserved by natural selection even in the face of a readily available mutation (putting some random enhancer on the DNA next to it).  Which would mean that some very immediate selective benefit for homosexuality has to exist from the perspective of the mother.
 * Are you sure that a selective benefit has to have occurred? I mean, couldn't there be a gay germ instead which likewise evolves along with humans--thus ensuring that any immunity that humans will develop to this pathogen will become meaningless? Futurist110 (talk) 01:30, 3 October 2018 (UTC)


 * That said, Cochran's speculation isn't necessarily wrong -- anything is possible in biology, always. One can imagine that a foreign antigen could influence rejection of some other protein, like lone star tick causing meat allergy.  The antigen could, in theory, be just about anything - mosquito saliva, rose thorns, or a virus.  But the problem is, I am not aware of any demonstration that homosexuality has ever not existed in any human society, so how can it be an environmental factor?
 * I have heard either Cochran or someone else previously make the claim that homosexuality (or at least male homosexuality) doesn't appear to exist in hunter-gatherer populations. Futurist110 (talk) 01:30, 3 October 2018 (UTC)


 * It could be interesting to look into whether this particular neuroligin is responsible for the specificity of synapses between potential pheromone receptors (some orthologs are allegedly pseudogenes, but I'm suspicious of selenocysteine involvement) in the vomeronasal organ, and GnRH-expressing neurons that pass through the terminal nerve to the hypothalamus. If this antibody response can alter the determination of which odor is a pheromone, then it should be able to condition recognition of one sex rather than another. Wnt (talk) 01:50, 29 September 2018 (UTC)
 * Can this antibody response also alter the blueprint of one's body that one has in one's brain? Basically, I'm wondering if this antibody response could likewise cause gender dysphoria. Futurist110 (talk) 01:30, 3 October 2018 (UTC)


 * Here is a list of possible ways that natural selection can select for homosexuality as a trait that increases the success of an individual in reproducing and passing their genes on to the next generation: [ https://sites.psu.edu/evolutionofhumansexuality/2014/03/05/selection-for-homosexuality/ ]. --Guy Macon (talk) 04:38, 29 September 2018 (UTC)
 * Relevant articles: biology and sexual orientation and environment and sexual orientation. --47.146.63.87 (talk) 22:12, 29 September 2018 (UTC)
 * That article looks like a good review of at least most of the leading ideas. Problem?  (a) Heterozygous advantage implies there is a "gay gene", which would have been mapped and cloned by now.  People have tried hard and failed to map any one locus on the chromosome.  (b) Altruism seems iffy in the article itself, as it is hard to explain how the homosexual can improve transmission of his genes that much in third parties; but see below.  (c) A polygenic trait seems like a winner --- however, if women can simply express this neuroligin to prevent this antibody effect, then they can have a single gene trait that overrides it all, which is why I got excited to see the article.  And (d) antagonistic pleiotropy only would make sense if the antibody response could also improve reproductive success (how?)
 * However, this paper introduces another possibility, which is that the mother could be selecting for her success, not the offspring's. It is always easier to tell somebody else to be altruistic than to be altruistic yourself, and so I think this might change some of the numbers, but I haven't looked into the math of altruism. Wnt (talk) 00:05, 30 September 2018 (UTC)

Diamond valuation
Is there someplace online where you can get a general idea of the value of a daimond (or even minor gemstones like, say, citrine)? I was reading about the 4Cs and am trying to figure out valuation by altering certain digits. Say how much would something like this cost? Color: I; Clarity: SI2; CTW: 0.200; Cut: RoundLihaas (talk) 09:41, 29 September 2018 (UTC)
 * This was the first hit on google for "diamond valuation", and puts your diamond's value at $147.42. 2400:D400:9:1268:306:200:0:10B0 (talk) 10:12, 29 September 2018 (UTC)
 * It's not clear from your post whether you're buying or selling. The price of a synthetic gemstone will generally be much lower than that of a "natural" one. Whether buying or selling, if you want a "natural" stone, you will likely get widely varying prices from different establishments; the market is intentionally opaque and full of collusion so you'll give up and just take whatever price is offered. (For instance, several of the largest U.S. jewelry store chains are owned by the same company.) --47.146.63.87 (talk) 22:07, 29 September 2018 (UTC)


 * This is a very old article but still relevant. 173.228.123.166 (talk) 22:19, 29 September 2018 (UTC)
 * There is a company called the Jewelry Exchange in Redwood City, California that advertises "diamonds guaranteed to appraise for double". That ridiculous slogan indicates that diamond prices are mushy and subjective, as opposed to gold prices, for example. Cullen328  Let's discuss it  22:23, 29 September 2018 (UTC)
 * That's what I head, especially if they are lab made vs. natural.
 * Thanks, anywasy, yall.Lihaas (talk) 22:59, 29 September 2018 (UTC)
 * We have an article, though it's in bad shape. (No Cal resident? As the article says, their headquarters are down here, so here their ads always tout "The Jewelry Exchange in Tustin". I think they've been running the same TV ad for over 20 years.) --47.146.63.87 (talk) 08:11, 30 September 2018 (UTC)