I knew that Yao Ming’s parents are very tall. Though his father, at 6’7, arguably contributed less than his mother, at 6’3, which is farther above the female mean in standard deviation units. But check this out from Superfusion: How China and America Became One Economy and Why the World’s Prosperity Depends on It:
Yao had essentially been bred. Both his parents played basketball. His 6’2 [different height from Wikipedia -Razib] mother, Fang Fengdi, perhaps the tallest woman in China, had been married to an even taller man. She had served as a Red Guard during the height of the Cultural Revolution and had been an ardent Maoist. She enthusiastically participated in the glorious plan of the local government to use her and her husband to produce a sports superstar. The Shanghai authorities who encouraged the match had gone back several generations to ensure that size was embedded in the bloodline. The result was Yao, a baby behemoth who just kept getting bigger.
What’s the chance of Yao? Let’s start with his mother being 6’3, his father being 6’7. Let’s assume that the genetic potentiality of Chinese women leaves a median height of 5’2, and men at 5’8. I suspect I’m low-balling this because there’s likely a fair amount of variability within China, with northerners being taller. Additionally, if Yao’s mother lived through the Cultural Revolution I’m wondering if she and her husband are even at their full height assuming normal nutrition. But let’s go with that. With 2 inches per standard deviation, ~85% heritability, you’d expect any of their children to be 6 standard deviations above the population norm in height (sex corrected). For a male that’s 6’8 (using the 5’8 figure as the median). Yao’s taller than that. In fact, at 7’6, he’s 5 standard deviations above the expected value. A freak if you will.
I think that that indicates that I’m being too conservative about the genetic potential of Yao’s parents, the full median height of the source population from which they derive assuming modern nutrition, and the heritability constraining to Yao’s family. In other words, I assume that the Chinese officials knew that neither of Yao’s parents were quite total freaks within their lineages, which indicates that there’ll be less regression back to the mean because their height is less likely attributable to non-replicable environmental variables. Though Yao is still freakishly tall in relation to both his parents, so I don’t think he was inevitable. Though of course the odds of someone of Yao’s height being born to his particular set of parents was orders of magnitude higher than for two random Chinese.
Note: To do the back-of-the-envelope I just used the breeder’s equation. Probably so far above the norm there are more non-linearities at work so that deviations from the expected values are probably higher. I guess only the Chinese officials who did the genealogical inquiries will know….
Razib Khan’s degrees are in biochemistry and biology. He has blogged about genetics since 2002, previously worked in software development, is an Unz Foundation Junior Fellow and lives in the western US. He loves habaneros.
August 1st, 2010 at 9:18 am
Interesting theory, but it seems to be mostly speculation. I’d like to know what the hard evidence of this is. In America, tall people like to marry tall people, and basketball players like to marry basketball players. I know of one such case personally, and one of their daughters turned out to be slightly above normal height and another ended up about 6’5″.
August 1st, 2010 at 9:25 am
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August 1st, 2010 at 9:33 am
“Bred” seems like a stretch. I’m a relatively tall man, and I’ve noticed that girls about say . . .6’2″ seem to be more attracted to me; I imagine in response to the rarity of meeting a man taller than they. Super tall women could be a self selected group for coupling with super tall men, which doesn’t really require an eye towards breeding.
August 1st, 2010 at 9:39 am
Regression to the mean tends to be the bane of human selective breeding. Not to mention the fact that physical tallness really isn’t a survival characteristic given the medical problems that very tall people often encounter.
August 1st, 2010 at 9:52 am
I’d like to know what the hard evidence of this is.
do you bother to read the post? the author of the above book could be making up the story, or transmitting a falsehood, but he basically indicates that they investigated the backgrounds of two very tall people. probably to ascertain whether they deviated too much from their family, and so may not be able to transmit heritable characteristics. certainly tall people assortatively mate. but the indication is clear that the match was strong encouraged by the party.
Regression to the mean tends to be the bane of human selective breeding.
not here. i assumed heritability was 85%. yao is FAR taller than he “should” be. there may be an error in the parameters though.
August 1st, 2010 at 10:11 am
Razib, you say that height has 85% heritability, but is that broad or narrow sense? There could be lots of non-additive effects, so the additive effects might only account for, say, 40% of the phenotypic variance.
There’s also the distinct possibility, if his birth was planned, that he was dosed with hormones, so even if the heritability of height is 85% for normal people on normal diets, the effects of environment on Ming were much larger.
August 1st, 2010 at 10:12 am
last i checked, narrow. i wouldn’t have used it otherwise.
August 1st, 2010 at 10:12 am
and i acknowledge that that far deviated from the norm the heritability can miss a lot of the genetic dynamic.
August 1st, 2010 at 10:27 am
When your country has 1.4 billion people, eventually coming up with someone that’s 7’5″ doesn’t seem too crazy.
August 1st, 2010 at 10:32 am
mark, yes. i recall the main issue that most people who are 7’5 are physically ill though. the body does not scale up to that range well. to a 7’5 athlete is exceptional indeed.
August 1st, 2010 at 10:59 am
Women who begin menstruating at an early age often don’t express their genetic hieght, or at least I hope this is true as my towering sons both at or over 6 foot 4 inches tall look down four inches at me and ten inches over my faithful (?!?!) wife. These sons(?!?!) share an amazing number of my bad habits and look one hell of a lot like me, I think I would more seriously consider the faint mathmatical odds of them being mine if my wife didn’t have all sorts of tall folks in her family tree and began her periods at the ripe age of eleven. My guess is there is speculation by others about tall milkmen and I like to tease my wife. Too bad they inherited my clumsiness, I could have used a little help in their college education.
August 1st, 2010 at 12:41 pm
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August 1st, 2010 at 12:43 pm
Scientifically it would have been interesting to have seen E. Germany continue its efforts in this line. Beyond just matching successful athletes of certain types, with genetic methods you could start minimizing body parts useless for certain sports.
August 1st, 2010 at 1:45 pm
Genes for size (for IGF2) are only fully expressed if inherited from the father.
Most people tend to physically resemble their father more than their mother, with personality it’s the other way about.
August 1st, 2010 at 2:32 pm
Most people tend to physically resemble their father more than their mother, with personality it’s the other way about.
can i get a citation for that? (i’ve seen that mentioned, but provisionally, not as something which should be taken as a background fact).
genomic imprinting is real, but i’ve never heard that IGF2 was a large effect QTL for height. have you? cite?
August 1st, 2010 at 9:14 pm
Could some sort of chemical supplementation have been involved too? Short children can be treated with HGH before their growth plates fuse to achieve a greater adult height (I recall one kid I went to middle and highschool with who was very short with very short parents (father about 5′, mother about 4’10″, grandparents similar) who took HGH therapy from middle school onwards and ended up about 5’7″ or 8″, in contrast to his older brother and sister who were not treated and ended up 5’1″ and 4’10″, respectively). I don’t know if HGH is effective for increasing the height of children without growth deficiencies (a brief search on pubmed didn’t bring up anything on point, but Kawai et al. (1997) indicates that improved height velocity in non-GH deficient children may be offset by accelerated bone maturation caused by HGH), but if it does, I don’t doubt that Chinese sports system would do it.
August 1st, 2010 at 10:38 pm
There is no way that 6’2″ would have made his mother the tallest woman in China, even growing up during the cultural revolution. That is a ridiculous claim for the author to make. The first time I went to Shanghai and Beijing I was immediately struck by how big the people were, and that was only 6 years after the end of the cultural revolution. And not everyone starved during the cultural revolution, by any means. It’s a huge country with a huge population, and generalisations are very risky.
Volleyballers Xu Yunli and Zhao Ruirui are both 6’5″. Xue Ming is 6’4″. Wang Yimei is 6’3″. If you ever want your breath taken away, check out the beach volleyballer Chen Xue http://www.bvbinfo.com/player.asp?ID=7238 who is not only stunningly beautiful, she clocks in at 6’3″. She comes from Fujian, where people are notably shorter than they are further north. The current national basketball team has one woman who is 6’5″ and three who are 6’4″. That’s just a tiny sample, there are obviously very many more that big or bigger.
Having said that, there would be nothing surprising at all about the local government encouraging people with height and sporting ability to marry one another. This happens naturally anyway – most of the people that basketballers get to meet are other basketballers. But I wouldn’t take this author’s word on it.
August 1st, 2010 at 10:51 pm
well, that reduces the author’s credibility. though i have to admit i assumed that that was probably some hyperbole.
August 2nd, 2010 at 2:30 am
“you’d expect any of their children to be 6 standard deviations above the population norm in height (sex corrected). For a male that’s 6′8 (using the 5′8 figure as the median). Yao’s taller than that. In fact, at 7′6, he’s 5 standard deviations above the expected value. A freak if you will.”
When you write 5 standard deviations above the expected value you are referring to the 6 standard deviations above the population norm right? I first misunderstood that sentence.
August 2nd, 2010 at 2:55 am
I thought his exceptional size might involve some unnoticed, acquired condition. But then I found a picture of the Lanier Brothers, MZ twins standing 7 ft 6 – both.
So apparently you can get significantly taller than your parents, just on your own genes. A good illustration of the difference between narrow and broad heritability: gene-gene interactions do exist.
Robert “2.72m” Wadlow died of an infection, just a few years before antibiotics entered common usage. He was still growing, at age 22. Makes you wonder where (if!) it would have stopped.
August 2nd, 2010 at 3:26 am
Yeah. I read the whole thing as hyperbole. By the time Yao would have been conceived, a lot of people were very definitely over the cultural revolution and fervent Maoism, including former Red Guards, and Deng was well into his reforms. No one seems to be accusing Andre Agassi and Steffi Graf of trying to selectively breed a tennis star for the greater glory of the USA, although they have themselves alluded to it, maybe jokingly.
On the calc, you obviously realize that the national means on height are not a good indication of mean heights around Shanghai, due to the general height gradient from north to south. The south is very populous, so this has a big effect on the means. Locals in the furthest south, on Hainan Island, look more like Indonesians than Han, including in size. They’re tiny light-brown people. Very cute. You could probably reasonably conservatively assume 5’4″ and 5’9″ for Shanghai.
I see that Yao is married to Ye Li, a former national team basketballer who is 6’3″. It’s going to be interesting to see how their daughter turns out.
By way of an amusing anecdote (or at least I found it entertaining at the time) I was walking to work one morning when I was surrounded by several members of the Chinese women’s national volleyball squad, who had been out on a training run and clustered on the sidewalk for a gossip and a giggle. They didn’t notice (or didn’t care) that they had me surrounded and trapped because they were talking to each other over the top of my head. (My recent true height is 5’10″.) True story.
August 2nd, 2010 at 6:08 am
Hello,
Friedrich Wilhelm I
http://en.wikipedia.org/wiki/Friedrich_Wilhelm_I_of_Prussia
had a regiment of very tall grenadiers : “Lange Kerls”.
He payed a lot of money (otherwise he was very saving) to
get the tallest men from all over Europe.
He tried to breed those tall grenadiers, wthout success.
It is reported, that one of the problems of those grenadiers
was bad health. All this in spite those grenadiers were
not extremely tall by today standards.
Regards
Georg
August 2nd, 2010 at 6:40 am
#20 toto, interesting comparison between Robert Wadlow and Zeng Jinlian (female):
http://en.wikipedia.org/wiki/Zeng_Jinlian
who died in 1982 and who clearly shows that Karabell was either being flippantly ‘amusing’ or economical with the truth when he claimed that Yao’s mother was “perhaps the tallest woman in China”. She was nowhere close. Yao’s mum was 6’2″ or 6’3″, Zeng Jinlian was over 8’1″ when she died aged 17 in 1982, poor thing.
The main thrust of Karabell’s book may be worthwhile, some of the reviews seem to suggest so, but in my humble opinion he does himself no favours by including this kind of cheap crap.
August 2nd, 2010 at 8:34 am
Former Chinese national team and WNBA player Haixia Zheng is 6″8 and 250+ lbs of solid muscle (she is much bigger than Charles Barkley). When I had dinner with her once (my cousin was her agent) I thought I was meeting a creature from mythology — she has an enormous head, a deep voice, but girlish mannerisms.
http://www.wnba.com/history/haixia_zheng.html
I wouldn’t trust the SuperFusion author as a careful researcher or investigator.
Re: your genetic calculation, protein and calcium consumption are much higher in China now or in Yao’s childhood than in his parents’. It’s likely that his parents have depressed heights relative to their genetic potential. Yao is probably still an upward fluctuation but not as much as in your estimate.
BTW, there is a noticeable height gradient when you travel between the south and north of China. People are much taller and more solidly built in the north.
August 2nd, 2010 at 10:00 am
Parental genomic imprinting of the human IGF2 gene
“We conclude that, as in the mouse, human IGF2 is parentally imprinted”
Study of Association between Common Variation in the Insulin-Like Growth Factor 2 Gene and Indices of Obesity and Body Size in Middle-Aged Men and Women
“our results suggest that common variation in the IGF2 gene may be associated
with adult height.”
Genomic imprinting in the development and evolution of psychotic spectrum conditions
“etiologies of psychotic spectrum conditions commonly involve genetic and epigenetic imbalances in the effects of imprinted genes, with a bias towards increased relative effects from imprinted genes with maternal expression or other genes favouring maternal interests”
August 2nd, 2010 at 10:19 am
yawnie, i know about igf2 being imprinted, in case i wasn’t clear. re: height, it’s not a large enough effect QTL for you to make a general assertion of relevance to this case, is it?* if it is in your judgement, that’s fine, but make sure to add citations in the future so we know what magnitude’s you’re talking about when doing so.
* as usual i have some concerns about replicability, but there’s a plausible reason why igf2 would impact height, so that’s attenuated here
August 2nd, 2010 at 11:38 am
When you write 5 standard deviations above the expected value you are referring to the 6 standard deviations above the population norm right? I first misunderstood that sentence.
that was confusing. i mean that parents of yao’s parents heights (assuming parameters i gave above) should have offspring of a particular expected value, 6 stds above the norm. he’s actually way above that, 6 + 5 = 11 stds above the pop norm!
but as steve hsu said, i think the big issue here is that parents are below genetic potential in height.
August 7th, 2010 at 4:08 pm
Razib I can’t believe you actually published this nonsense. It’s an embarrassment to your blog. Even a cursory search will reveal that Yao’s mother is no where close to the “perhaps the tallest woman in China” among other outright fallacies listed. There were 4 women over 6’4″ on the last Chinese women’s basketball team and I personally met at least 2 women in China over 6’2″. Not only are there women closet o 7 feet in China, there are without exaggeration literally millions of women in China over 6’2″
It’s insane that a blog about “About Gene Expression” would actually be that clueless about genetic diversity in a population pool of 1 and a half billion. Boggling actually.
As for Yao being “bred” realize that Chinese are people not dogs. Even the Communist party cannot force people to breed. Yao’s parents were set on a blind date by a mutual friend but their decision to marry and their (hard) life prior to Yao’s birth was entirely of their own making. Yao’s father worked as a longshoreman on Shanghai’s busy docks… hardly the kind of cushy life some Chinese mastermind would have his prize giant-breeding stud to be living lest his plan for world basketball domination reaching back generations would be wiped out in one industrial accident.
Now if you wanted to stir the pot you could talk about HGH use in China or Fang Fengdi’s history as a Red Guard but this stuff about Yao being bred is nonsense.
The smartest thing you posted was that Yao is a freak. Any way you look at it, Yao’s a 1 in a billion genetic outlier. Yao’s own wife is tall but it’ll take another genetic miracle for his kids to be anywhere as tall as he is.
August 7th, 2010 at 5:20 pm
dude, chill out. the only part of great interest was the claim that his parents were encouraged to marry (which i bolded). you may be right. i’ve reduced my confidence in the author’s credibility with follow up comments.
August 8th, 2010 at 12:28 pm
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