Archives for posts with tag: congenital adrenal hyperplasia

so i think the connection between inbreeding (or outbreeding) and the evolution of the “innate social aptitudes of man” [pdf] works something like this:

inbreeding in and of itself does not change the frequency of genes (alleles) in a population [pg. 65], but it does move them around, concentrating them in certain family lines.

if, then, some sort of genetic mutation arises in one family line which, let’s say for the sake of argument, results in the carriers somehow behaving more altruistically towards their fellow family members than strangers, and this results in them being able to increase their inclusive fitness, then that genetic mutation will be selected for.

it will really be selected for (i.e. the selection rate will be accelerated) because of the inbreeding because: 1) since the inbred family will have greater than average numbers of this “altruism gene” because it is inbreeding, its members will likely execute a greater total number of altruistic behaviors towards one another and, so, they will really benefit fitness-wise from this new gene. also, 2) perhaps — perhaps — all else being equal, the inbred family members will feel even more strongly altruistic towards their fellow family members than an outbred family would since they are so much more genetically similar to their family members. to be honest with you, i’m not so sure about that second proposition, so i’m just going to skip it for now and focus on the first one.

wrt the first proposition, that the rate of selection of “genes for altruism” is faster in an inbreeding population is exactly what wade and breden found when they ran some models — the more inbreeding, the more rapid the selection of the altruism genes:

you can imagine why.

if you have a bunch of different families in a population, and one of those families possesses some sort of “familial altruism” gene which means that its members help each other out (or whatever) more than the members of the other families do, and this increases the fitness of a majority of this special family’s members, then they are simply going to be more successful than the other families. they’ll leave more descendants behind and, thus, more of those genes behind. IN ADDITION, if this successful family ALSO inbreeds, each of its members is much more likely to have at least one, or even two, copies of this familial altruism gene, so more members of this successful family will be even more altruistic to each other and voilà! — they’ll increase their fitness and success even more than they would have done without the inbreeding.

these familial altruism genes — genes that lead to behaviors in which individuals somehow favor their own family members over non-family members — and by family members i mean extended-family members — are only going to arise, of course, in a population in which there is more than one family. if you’ve got some tiny band somewhere that has absolutely no contact with any other group (doubt that’s ever existed), then my evolutionary scenario simply won’t happen. it’s the competition between the individuals from the different families that is driving this.

naturally, genes in any population — even an inbreeding one — won’t remain restricted to any one family for very long. no family anywhere inbreeds 100% exclusively, so if some successful familial altruism genes do arise in some inbreeding family somewhere, they will quickly spread to the other families in that population. thus, there is probably an ongoing familial altruism genetic arms race in inbreeding populations.

also, i think fewer familial altruism genes — or not such strong ones, perhaps — are going to arise in a comparatively outbreeding population. the accelerated selection due to the inbreeding won’t be there, nor will this arms race to keep one step ahead of the joneses when it comes to familial altruism. additionally, i think that in an outbreeding population, there’ll be greater selection pressures than in an inbreeding population for “reciprocal altruism” genes — i.e. genes which lead people to be willing to cooperate more with non-family members — since more of those sorts of behaviors will likely be required to be successful in life.
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so what do these “familial altruism” genes look like?

i dunno.

maybe there are differences in oxytocin-related genes? — the luuuuv hormone that “turns out to be the hormone of the clan.”

or — ya’ll know that i’m kinda fascinated by interclan fighting which is the flip-side of being nice to your family (i.e. be extra un-nice to your non-family) — so maybe one familial altruism gene is the “warrior gene” (MAO-A gene)? dunno.

one that i speculated about before is CYP21A2, the gene connected to congenital adrenal hyperplasia (CAH), a recessive genetic condition which affects the production cortisol which, in turn, affects the production of androgens (like testosterone) — notably, in the most common form of CAH, androgen levels are increased. the condition is a recessive one, so you need to have two copies of the deleterious allele to have the condition, but as i mentioned in my previous post on CAH, carriers with one copy of the allele have been found to have excess androgens — and androgens have been connected to aggression. (also, children with CAH have been found to have smaller amygdalae, so … they’re less fearful? don’t know if this also holds true for adults with CAH.)

increased aggression? fighting at the drop of a hat? interclan fighting? see where i’m going with this?

the interesting thing is — at least i think it’s interesting — is that there are different frequencies of CAH found in different populations. what we’d really want to know, of course, are the gene frequencies for CAH for different populations, but in lieu of those … here are some incidence rates of classical CAH in different populations [numbers acquired from or via here and here]:

1:282 – Yupik Eskimos, Alaska
1:2,141 – La Reunion
1:4,081 – Western Australia Aborigines
1:5,000 – GLOBAL
1:5,000-7,000 – Moroccan Jews
1:5,041 – Zurich, Switzerland
1:7,000 – Kuwait
1:10,866 – France (Whites)
1:10,866 – Italy (Whites)
1:11,500 – Sweden
1:11,764 – Netherlands
1:14,300 – Hungary
1:14,403 – Croatia
1:14,500-23,344 – New Zealand
1:14,869 – Western Australia
1:15,518 – Emilia-Romagna, Italy (Whites)
1:15,800-18,000 – Japan
1:17,098 – Scotland
1:19,939 – Minas Gerais, Brazil
1:20,000 – Norway

i dunno, but i see — maybe — the more inbred clannish fighters (yupik eskimos, moroccan jews, kuwaitis) having more cases of CAH than the more outbred peaceniks (new zealanders, norwegians, even northern italians). also…

- “The Texas data indicate a lower disease frequency in African-Americans when compared with Caucasians, and international data indicate higher frequencies in native Yupik Eskimos, Brazilians, residents of La Reunion, and Filipinos.” [source]

- “The prevalence of the disease [non-classical CAH] in Ashkenazi Jews was 3.7%; in Hispanics, 1.9%; in Yugoslavs, 1.6%; in Italians, 0.3%; and in the diverse Caucasian population, 0.1%.” [source] (non-classical CAH refers to a less severe form of CAH which might not get noticed until adulthood when it expresses itself in features like a woman having, perhaps, a bit too much facial hair.)

again, what we’d really want to know are the gene frequencies for CAH in different populations. then the über-human savants that we call population geneticists could do their math wizardry to see if these genes were under positive selection or not (zey hav vays av mayking ze data talk). (another interesting thing, btw, is that there are many different mutations in this gene which cause a range of CAH conditions from mild to severe — and different mutations are more common in different populations — see here and here and here for instance.)

of course, maybe these mutations in CYP21A2 aren’t being selected for for increased aggression/upside-down familial altruism. maybe it’s something else. witchel, et al., found that heterozygotes for mutated CYP21A2 alleles (i.e. individuals with just one copy of the cr*ppy gene) had increased cortisol levels and cortisol is, apparently, important for the immune system, so maybe these mutants simply survive infections better. others have found a possible connection between higher iq and CAH (masculinization = higher iq?) — see here and here and here — so maybe that’s it.

or maybe these genes are not being selected for at all. however, fertility rates of people (women) with CAH are low, so it seems like a strange bunch of genes to have around if they don’t have some sort of benefit.

previously: inbreeding and the evolution of altruistic behavior and looking for altruism genes and visions of altruism genes

(note: comments do not require an email. CAHt.)

some eskimo groups engaged in blood feuds. ruh-roh. from Eskimos and Explorers about the mackenzie eskimos (mackenzie inuit) [pg. 195]:

“Murders committed in anger were relatively common, and blood revenge led to further retalitory murders and family feuds. In one instance a woman’s rejected suitor killed her as she slept. In another a man who refused to sell his belt was stabbed in the back and killed by a person who hoped to buy the belt.

“A feud that erupted about 1860, soon after intensive historic contact, was recorded by Nuligak, a Mackenzie Eskimo. One man hoped to marry the daughter of another, but the father of the girl refused to permit the match. The rejected suitor took a valuable steel-bladed knife from one of the father’s younger sons, and the father was furious. At the first opportunity he killed not only the thief but one of his companions. As the feud spread, a cousin of the original murderer allied himself with the thief’s relatives, and more people were killed. Finally the father of the girl and the betraying cousin killed each other, but the feud continued on. As Nuligak wrote, ‘In the olden days the Inuit slew those who killed their kinsmen. One vengeance followed another like links in a chain.’

“Terrible feuds have been reported among most Eskimos, and they often spanned a number of generations….”

dunno about the mackenzie inuit, but the yupik eskimos (are mackenzie eskimos yupik eskimos? i didn’t figure that out…) have one of the highest incidence rates of congenital adrenal hyperplasia (CAH) — and carriers of CAH alleles can show “symptoms of androgen excess” — like being more aggressive, perhaps? dunno. melykin pointed out that there are high rates of violent crime in areas of canada populated by eskimos.
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from ed west in the telegraph u.k.:

“The EU was dreamed up in French and German. That’s why the British have never fitted in”

“The European project developed in the region between Paris, Brussels and the Rhineland, the heartland of the old Frankish Empire….”

isn’t THAT curious?! the modern european feudal project (for what else is the e.u. apart from feudal with a bunch of local [i.e. national] politicians playing vassals to the eurocrats?) had its origins pretty much right where medieval feudalism got going — austrasia. what is it about those people in that region?
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more on extended family human traffickers (can’t we just call them slavers?) from the balkans:

“Police bust Balkan child trafficking ring in Nancy”

“French police have arrested seven people for running an international child trafficking ring in Nancy, north east France.

“The ring is thought to have bought children from Macedonia or Kosovo for €1000 to €1500 and then sold them on to Belgium and Germany for €10,000.

Seven members of a family originally from the Balkans were arrested on Tuesday after a month of police investigation.

“According to local paper Est Républicain, several other members of the family had also been arrested in Germany in relation to the ring.

“Police took in two girls, both about 12-years-old, for questioning. They say they do not believe the girls were subjected to sexual abuse or used as slaves, but traded in line with ‘local customs’ in the traffickers’ home countries.”

in line with WHAT “local customs”?!
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corruption in china — it’s a family affair. from the nyt:

“Billions in Hidden Riches for Family of Chinese Leader”

“[N]ow 90, the prime minister’s mother, Yang Zhiyun, not only left poverty behind, she became outright rich, at least on paper, according to corporate and regulatory records. Just one investment in her name, in a large Chinese financial services company, had a value of $120 million five years ago, the records show.

“The details of how Ms. Yang, a widow, accumulated such wealth are not known, or even if she was aware of the holdings in her name. But it happened after her son was elevated to China’s ruling elite, first in 1998 as vice prime minister and then five years later as prime minister.

“Many relatives of Wen Jiabao, including his son, daughter, younger brother and brother-in-law, have become extraordinarily wealthy during his leadership, an investigation by The New York Times shows. A review of corporate and regulatory records indicates that the prime minister’s relatives — some of whom, including his wife, have a knack for aggressive deal making — have controlled assets worth at least $2.7 billion….

“Unlike most new businesses in China, the family’s ventures sometimes received financial backing from state-owned companies, including China Mobile, one of the country’s biggest phone operators, the documents show. At other times, the ventures won support from some of Asia’s richest tycoons. The Times found that Mr. Wen’s relatives accumulated shares in banks, jewelers, tourist resorts, telecommunications companies and infrastructure projects, sometimes by using offshore entities.

“The holdings include a villa development project in Beijing; a tire factory in northern China; a company that helped build some of Beijing’s Olympic stadiums, including the well-known ‘Bird’s Nest'; and Ping An Insurance, one of the world’s biggest financial services companies.

“As prime minister in an economy that remains heavily state-driven, Mr. Wen, who is best known for his simple ways and common touch, more importantly has broad authority over the major industries where his relatives have made their fortunes. Chinese companies cannot list their shares on a stock exchange without approval from agencies overseen by Mr. Wen, for example. He also has the power to influence investments in strategic sectors like energy and telecommunications.

“Because the Chinese government rarely makes its deliberations public, it is not known what role — if any — Mr. Wen, who is 70, has played in most policy or regulatory decisions. But in some cases, his relatives have sought to profit from opportunities made possible by those decisions.

“The prime minister’s younger brother, for example, has a company that was awarded more than $30 million in government contracts and subsidies to handle wastewater treatment and medical waste disposal for some of China’s biggest cities, according to estimates based on government records. The contracts were announced after Mr. Wen ordered tougher regulations on medical waste disposal in 2003 after the SARS outbreak.

“In 2004, after the State Council, a government body Mr. Wen presides over, exempted Ping An Insurance and other companies from rules that limited their scope, Ping An went on to raise $1.8 billion in an initial public offering of stock. Partnerships controlled by Mr. Wen’s relatives — along with their friends and colleagues — made a fortune by investing in the company before the public offering….”

tptb in china NOT amused by nyt story.

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so, the tidbit of info in the previous post about the mccoy clan being predisposed to von hippel–lindau disease (75% of the mccoy clan have had tumors on their adrenal glands — says so in wikipedia so it must be true), got me to thinking about what sorts of congenital conditions might offer clues to “genes for altruism” a la cochran, hardy & harpending [pdf].

re. the mccoys and von hippel–lindau disease:

“Some descendants of the McCoy family (involved in the Hatfield-McCoy feud of Appalachia, USA) as well as the Elliotts have VHL. In an article appearing in the Associated Press, it has been speculated by a Vanderbilt University endocrinologist that the hostility underlying the Hatfield–McCoy feud may have been partly due to the consequences of von Hippel–Lindau disease. The article suggests that the McCoy family was predisposed to bad tempers because many of them had a pheochromocytoma, which produced excess adrenaline and a tendency toward explosive tempers.

hmmm. excess adrenaline. that could certainly be beneficial if the sort of altruistic behavior you need to have to be reproductively successful is the kind where you’re willing to go out and fight the competing clan on behalf of your own.

so i started thinking about everybody’s favorite aggressively tribal inbreeders — the arabs — and aaaall the congenital disorders they have and if any of them might be related to adrenalin and/or the adrenal glands.

here’s one — congenital adrenal hyperplasia:

“Congenital adrenal hyperplasia (CAH) refers to any of several autosomal recessive diseases resulting from mutations of genes for enzymes mediating the biochemical steps of production of cortisol from cholesterol by the adrenal glands (steroidogenesis)…. CAH is a genetic disorder in which girls are masculinized because the adrenal glands secrete large amounts of androgen during prenatal development. The extra androgen does not affect a baby boy’s physical development, but in baby girls it can enlarge the clitoris so that it resembles a penis….

“Most of these conditions involve excessive or deficient production of sex steroids and can alter development of primary or secondary sex characteristics in some affected infants, children, or adults.”

so here’s a genetically recessive condition — so, like sickle cell anemia, you need to have two copies of the “bad” allele to have the condition — that masculinizes girls ’cause the female fetus is exposed to lots of androgen. and male fetuses are not affected? at all? couldn’t they be “extra” masculinized in some way? maybe that’s not the case, but it sure makes me wonder.

and androgen certainly has interesting effects on the brain:

“Circulating levels of androgens can influence human behavior because some neurons are sensitive to steroid hormones. Androgen levels have been implicated in the regulation of human aggression and libido.”

well, what do you need to survive in a warring clannish/tribal society but high levels of aggression? amirite?!

the world-wide incidence of CAH is 1:14,199 live births. in kuwait it’s 1:7,000 and amongst moroccan jews it’s between 1:5000-1:7000 (i know, i know — they’re not arabs — but they’re part of the same sort of clannish, inbreeding society being in morocco). there are also apparently high rates in egypt (alexandria), but i don’t know what the prevlance is. it’s also considered a problem in tunisia, jordan, oman, uae and saudi arabia.

here’s a breakdown of the prevalence in several populations:

1:282 – yupik eskimos of southwestern alaska
1:2,141 – edit: la reunion, france (or la reunion, france? see comments.)
1:5000-1:7000 – moroccan jews
1:7,000 – kuwait
1:10,866 – france (whites)
1:10,866 – italy (whites)
1:14,500 – new zealand
1:15,800 – japan
1:17,098 – scotland

carriers of one allele related to CAH often exhibit “symptoms of androgen excess.”

androgen excess? aggression? high prevalence in the arab world? clannish/tribal societies? possible “genes for altruism”?

dunno. just a thought.

previously: hatfields and mccoys and which altruism genes?

(note: comments do not require an email. chaaaaaaarge!)

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