I heard recently that certain pymgy tribes have evolved such a different genetic structure that it is no longer possible for other ‘humans’ to reproduce with them. Is it true? If it is, does this not raise serious ethical questions? They would technically not be categorized as human beings.
Furthermore, why are pygmies so small anyway?
Hey, a new spin on racism! Kewl! 
“Is it true?” No. Pgymies are members of the species homo sapiens and as such can breed with any other members of the same species.
Why are they so short? It’s genetic. They’re short for the same reason that the Watusi are tall–heredity.
*(Jumping up from book-strewn table)
Your Honor, I move to strike sentence 2 of the OP, on the grounds that it is a debateable question.*
Hey, there, bmerton. Welcome to the SDMB. If we skip the ethical part, this is a fascinating question which will get some great answers here in General Questions.
You also might want to dig on the search function in the top right corner. A search for the word “pygmy” in GQ for the past 2 years yields 23 threads, some about people humping each other, some about people humping all sorts of other critters.
Which happens to be something I’m intensely interested in, on a purely theoretical basis, of course. So I’m looking forward to an answer.
Why is this so? Maybe non-pygmies should not be categorized as human beings, for the same reason.
IIRC I think remember reading in National Geographic at least 10-20 years ago that some pygmy tribes were dying out because the female pygmies preferred full statured men when available and that this was causing the population base to shrink.
I can imagine that some pygmy women might have difficultly bearing normal sized babies but I don’t think it is a “genetic” incompatibility as such. Any problems in this area are probably related to pre-natal head size issues.
Some genomic info re pygmies. It refers primarily to differences in the way insulin is processed and that pygmies are different genetically from other African population groups but no more different than one African group is from another. Apparently there is more genetic diversity between distinct African population/genomic groups than between an Australian Aborigine and a German. Interesting.
http://www.univ-lille1.fr/pfeda/Ngonut/1997/9706d.htm
“Although I agree that nearly always environmental hardship is the main cause of short stature, I would not discount a genetic component in the pygmies. This is because of the placental mitochondrial DNA sequencing data. there are about 2 base substitutions per 5 generations (100yrs) and no repair machinery - so that from the sequences a latest-common-ancestor for two peoples can be determined. Surveys show that the genetic diversity within Africa (at least 7 different pedigrees) is greater than in the rest of the world put together. I (Caucasoid) am closer genetically to an Australian Aboriginal than a Dinka is to a Hotentot. Showing that the rest of the world (including the Ok people) has more or less the same genetic growth does not necessarily hold for African groups. Clearly the rift-valley people and the west-coast population that gave rise to the slaves have growth genetics like the rest of the world - but pygmies, who do NOT have normal IGF-I or in-vitro ICF-I responses or pubertal growth spurt, could well have a genetic growth curve difference. They almost certainly ALSO have nutritional deprivation however. The topic must remain sub judice until we have the data.”
Where’s Collunsbury when you need him?
I’ll try to respond to this.
Yes, genomic divergence among Africans is the highest in the world. The genetic differences between certain West African groups and other Southern African groups are the largest divergence in all of humanity, according to mitochondrial and Y chromosome haplotypes. Noteably, the Khoisan of South Africa represent a significant branching of humanity not represented anywhere else in the world, while most of the Bantu fall in with the European, Native American, and other peoples around the world. Most of the genetic analysis has been done with the Khoisan, not with the East African pygmies (of which I know very little).
This does not impair reproduction, to the best of my knowledge. Since I do study genetics, you would figure that I would have heard about it if it were true.
IGF-1 is a liver receptor that is somewhat involved in insulin response, but is more important in human growth hormone (hGH) response. IGF and IGFR (its receptor) are implicated in many syndromes which cause overgrowth : Beckwidth-Wiedemann Syndrome and gestational diabetes (here tying into the insulin processing) are two which I can think of off the top of my head.
I read an article some years ago which studied the “why are pygmies so short?” question. The infants of these tribes are, in fact “normal sized” at birth, meaning they fall into the same range of body weight, length, and head size as infants from all other parts of the world.
Nor is it (entirely) a matter of nutrition, as people from these short-statured tribes who grow up on a diet simillar to taller people around them nevertheless remain short.
Apparently the only difference was a lack of “growth spurt” in adolescence, which they consistently do not experience. It’s not that they don’t grow, it’s that most other humans at a certain point start to grow much faster than these tribes and thus wind up taller.
Only if you try to have sex standing up.
So, if I may,…why was there a dance named after the Watusi?
I’m serious!
This is also discussed in the link. For some (not all) pygmy groups the small size is not necessarily “growth spurt” related but is seen throughout the life/growth cycle from birth onward.
ie
"These results indicate that suppression of pygmy growth does not occur solely at puberty, but from birth onward. Furthermore, they suggest that conclusions concerning the lack of an adolescent pygmy growth spurt have been premature and must await studies of older pygmy sub-adults of known age. "
Nobody tell Autumn Wind Chick about this thread if you want to keep it in GQ.
I have worked with pygmies in Africa. (In Zaire I once went out net-hunting with 20 Mbuti pygmies in the Ituri Forest to catch forest antelope for a research project.)
I have never heard that any pygmy group was not interfertile with other people. Pygmies tend to live in close association with neighboring normal-statured Bantu agriculturalists. There is regular intermarriage between pygmies and Bantus, but it seems to be almost exclusively Bantu males with pygmy females, rather that the other way around - I would imagine due to cultural preferences that males should be taller than females.
The pygmies sometimes go off to hunt and gather food in the forest, and trade meat and honey for agricultural products. They also work for Bantu households in exchange for food. In these circimstances, I don’t see much reason to suppose that pygmy children would be less well nourished than their neighbors (at least enough to account for the considerable difference in height). In fact, pygmy children could well get more protein than Bantu kids.
Regarding the OP, even if certain pygmies were not able to interbreed with other people, that would not necessarily mean they wouldn’t be “human beings.” “Human” can be used in two senses: a member of the species Homo sapiens; or of a “human” grade of intelligence and self-awareness. Neandertals were possibly a different species from H. sap., but were quite likely of a human grade of self-awareness. Even if a modern group were found to be technically not H. sap., ethically I don’t see any reason not to consider them “human.”
Neandertals had larger brain cases than we do. They were also physically more rugged. I wonder what really killed them off? Damn, hijacking again.
'S’okay, DP. But, no offense, you’re bush league, kid. Step aside.
[mother of all hijacks commences]
Ahh, 1962, a good year to do the Wah-Wah-Watusi. Got all the way up to #2 on the Billboard charts.
Lyrics, posted by some public-spirited Netizen.
Watch Tom dance the Watusi.
And, step by step, how to do the Watusi yourself.
I love the Internet.
[we now return you to your regularly scheduled talking heads PBS panel discussion about genetics]
[which Colibri could have spiced up just a bit with some juicy details about those pygmy/Bantu courtship rituals]
[if he had wanted to]
[but evidently he didn’t]
[so]
[back to the chromosomes]
[and the pledge breaks]
[sub]wah wah tooseeee[/sub]
snicker
As far as I know, it’s probably along the lines of “So Ewa, what’s your sign, anyway?” But I was a little limited in my research there, since my Swahili is none too good*. (I do, however, have some good anecdotes about the courtship rituals of the Yaminahuas of the lower Urubamba.)
But I’ll see what I can find out, DDG. 
I’m always happy to cater to the prurient interests of the TM.
(*I mainly learned that Sikopishi watu bidhaa = “I don’t give credit.”)