In truth, the actor playing the banjo players is not inbred.
Posted on 11/06/2018 12:24:18 PM PST by ETL
Early humans faced countless challenges as they fanned out of Africa: icy conditions, saber-tooth cats, and, according to a new study of ancient skeletons, an unusually high number of birth defects, both debilitating and relatively inconsequential. It’s unclear why such abnormalities seem to be so common, but scientists say one strong possibility is rampant inbreeding among small hunter-gatherer groups.
“This paper represents a valuable compilation,” says Vincenzo Formicola, an anthropologist at the University of Pisa in Italy who wasn’t involved in the new work. “Many cases reported in the list were unknown to me and, I assume, to many people working in the field.”
Many human fossils from the Pleistocene (roughly 2.5 million B.C.E. to 9700 B.C.E.) have unusual features. For example, femur bones with abnormal bowing have been found from China to the Czech Republic. The skull of a toddler found in the Qafzeh cave in Israel had a swollen braincase consistent with hydrocephalus, a condition in which fluid floods the skull. And a fossilized man in Liguria in Italy had a bowed right upper arm bone but a normal left one.
By and large, these were viewed as one-off curiosities. But Erik Trinkaus, a paleoanthropologist at Washington University in St. Louis, Missouri, noticed a pattern: These skeletal deformations seemed to be suspiciously common in the fossil record.
So Trinkaus did the math. He assembled data on 66 individuals with skeletal abnormalities mostly dating to the past 200,000 years. The fossils, most from young adults, were found in sites scattered throughout the Middle East and Eurasia and represent several different species of Homo. Trinkaus then researched how common their conditions are in modern human populations.
He found that about two-thirds of the ancient abnormalities occur in less than 1% of modern humans. Another dozen or so didn’t match any known modern developmental disorder. Trinkaus ran the odds that archaeologists would have uncovered so many ancient abnormalities by chance, and he found that it would have been a “truly, vanishingly small probability.” That suggests, he reports today in the Proceedings of the National Academy of Sciences, that early humans faced some cultural or environmental pressure that led to so many deformities.
One possibility, previously proposed by other researchers: Ancient people with skeletal deformities might have been seen as shamans and given careful burials, making their bodies more likely to be preserved and later found. Another: Pregnant mothers didn’t get enough of the right nutrients, leading to more skeletal disorders. But Trinkaus notes that, whereas some skeletal disorders like rickets affect the whole body, many skeletons were found with deformities on only one side of the body. He also says many fossils in his analysis show no evidence of special rites.
However, several bodies show abnormalities consistent with known genetic mutations, and multiple individuals from at least one site exhibited several different conditions, suggesting the people might be related. It’s thought that most human populations at the time were small and isolated, Trinkaus says. In those conditions, inbreeding can lead to widespread harmful genetic mutations.
Evidence of low genetic diversity among Pleistocene humans based on ancient DNA analysis also supports this hypothesis, says Hallie Buckley, a bioarchaeologist at the University of Otago in Dunedin, New Zealand. “Of all the arguments put forward … this seems the most likely explanation.”
Further analysis of ancient DNA at these sites might confirm inbreeding, but prepping samples for such investigations often means destroying them. “Ancient DNA has become increasingly viewed as a ‘magic bullet’ to shoot at any question about past human populations, but that may not always be justified,” Buckley says.
Siân Halcrow, Buckley’s colleague at the University of Otago, says that although she appreciates Trinkaus’s thorough cataloging, his paper has several weaknesses, most notably in its estimates of how common these abnormalities are in modern people—and how common they used to be. It would be better to compare the ancient rates to later populations in prehistory or early historic populations, she says, but unfortunately those data don’t exist.
No matter the cause, many of the deformities would have been debilitating. The fact that so many survived past childhood suggests early humans must have offered each other social support and medical knowhow, Trinkaus says. For example, although hydrocephaly is rarely a death sentence thanks to modern treatment, it can easily be fatal if left untreated. “The Qefzeh child with hydrocephaly lived until about 3 or 4 years old. When you consider it lived 100,000 years ago, that’s pretty amazing.”
“Early humans were genetically perfect, thus inbreeding was a good thing for them.”
Would only take a few generations for imperfections to crop up, however—which is why law against incest was written. It is notable though, there there were no laws on incest until Moses, about 1,500 BC. Abraham himself married his half-sister.
It is also interesting that Abraham’s nephew, Lot, was condemned....for sex with his own daughters (giving rise to the Moabite & Amonite nations)—so certain forms of incest were known as wrong (at least parent/child incest).
Noah was a pretty good genetic choke point for us all.
That said, there are two camps: (1) she was his half-sister (different mothers) or (2)Sarai was the daughter of Iscah and Abraham’s deceased brother Haran (and thus his niece).
The express language is unclear. The oral tradition takes the position that’s she was his niece.
Icky, either way, I agree.
can’t we just let sleeping dogs lie...
Certainly created mental abnormalities in today’s democrats.
Abnormalities in early Homo, such as bone thickening of the skull, scientists believe resulted in smaller brain size, thus began the branch that led to modern liberals.
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By the time the Law was given, Hebrews had been mixed with the sinful seed of Ham in Egypt.
That was why it mattered.
That's an awfully small sample. It is rarely emphasized how few ancient human remains we have discovered.
This is not to say that the hypothesis is stupid or anything, just that the evidence needed to do real analysis isn't exactly there.
In truth, the actor playing the banjo players is not inbred.
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But we know that the “oral tradition” began after the return to the land. Guesswork most likely, since Moses got his version directly from Yehova at Sinai.
I sure wouldn’t mary my sister (if I had one).
No Wilma, your brother can't come and stay for Christmas.
The most popular poster in my college dorm.
She actually visited our dorm, just prior to the last ice age.
I think a more “recent” collection of bones showing genetic abnormalities can be found in native Hawaiian excavations.
With bowlegged wimmin'.
That is disgusting!
That certainly wouldn’t surprise me. As I said, the hypothesis isn’t stupid, it just doesn’t have a lot of data available from the very distant past.
On the subject of inbreeding, I once read a book by a doctor in Saudi Arabia who called the Saudi royal family “an irreproducible laboratory of genetic defects.”
“But we know that the “oral tradition” began after the return to the land.”
No, it was given to Moshe at Mt. Sinai.
But I concur there are major issues with it; the written versions are not clearly recorded, conflict, and were prepared much later.
Hence, the two reasonable camps.
Arguing in your favor, would be that the narrower interpretation (half-sibling) would help explain the problem with fertility, whereas Abraham had no problem conceiving with Hagar.
Ha!
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