Archaic Genes in Modern People?

Science Magazine | 2005-04-22 | Elizabeth Culotta

[Pharmboy]

No---Down's Syndrome individuals have an extra chromosome, so instead of 46 like you and me, they have the odd number of 47. This produces the typical syndrome, but there is a broad range of its manifestations.

[Vaquero]

The chinese knew this already....the homo erectus branches in China were peopled with Shovel toothed specimens just like themselves.....

[PatrickHenry]

I can see interbreeding with Neanderthals, but not with Homo erecti based on this slight evidence.

But once you've had a taste of non-Sapiens, there's no place to draw the line. In for a dime ...

[AntiGuv]

Good point! However, the Neanderthals were much more closely related to Homo sapiens than were Homo erectus, and it seems more likely that they could've exchanged genes without leaving much of an imprint. To quote wikipedia:

It is generally accepted that both Neanderthals and Homo sapiens evolved from earlier "archaic" Homo sapiens, but the classification of Neanderthals depends on when in the timeline these modern humans are considered a separate species from the "archaic" forms.

So, it may in theory be the case that they were similar enough from a genomic standpoint that we haven't been able to distinguish the admixture. But more likely not! I'm quite skeptical of the idea myself. If so, where did all the distinctive Neanderthal features go? Stated differently, how could all the progeny bear such a remarkably indistinguishable resemblance to other Homo sapiens?

And the differences between Homo erectus and Homo sapiens makes the differences with Neanderthal seem downright trivial. Brain capacity alone: Homo erectus had 75% that of Homo sapiens. So, if they mated, where did all the retard hybrids go?? :)

[AntiGuv]

Check out the difference between a Neanderthal skull and a modern human skull; and this is trivial compared to a Homo erectus!

[SunkenCiv]

One last point I'd like to note is that a small survey which turns up just one person with a given haplotype could just as easily miss that person. All of a sudden the 4-5 million people represented by that person have 'dropped' to zero, and "vanishingly rare" is now "nonexistent" - although it's not. And, with a 7% margin of error, your extrapolated 4-5 million might actually be more like 60 million.

And with a 7% margin of error, it might actually be more like zero. Once again, a study shows there's no evidence for total Replacement and instead there's evidence for Multiregionalism. Strange, every time a DNA study is done, the result matches the morphological evidence for Multiregionalism.

[SunkenCiv]

But once you've had a taste of non-Sapiens, there's no place to draw the line.

Well put.

The Neandertal Enigma
by James Shreeve

Frayer's own reading of the record reveals a number of overlooked traits that clearly and specifically link the Neandertals to the Cro-Magnons. One such trait is the shape of the opening of the nerve canal in the lower jaw, a spot where dentists often give a pain-blocking injection. In many Neandertal, the upper portion of the opening is covered by a broad bony ridge, a curious feature also carried by a significant number of Cro-Magnons. But none of the alleged 'ancestors of us all' fossils from Africa have it, and it is extremely rare in modern people outside Europe." [pp 126-127]

[AntiGuv]

Yeah, I'm sure anthropologists just pulled the prevailing theory out their !

DNA from mitochondria (mtDNA), the Y chromosome, and ancient humans each suggest that the ancestors of all living people arose in Africa some time after 200,000 years ago, swept out of their homeland, and replaced archaic humans around the globe without mixing with them.

I guess "no evidence" is euphemism for "no evidence I find persuasive"......

[Varda]

If this is the same "haplotype X" than it has been found in Africa. I'm assuming haplotype X is referring to a mtDNA sequence.

"A maximum parsimony tree of 21 complete mitochondrial DNA (mtDNA) sequences belonging to haplogroup X and the survey of the haplogroup-associated polymorphisms in 13,589 mtDNAs from Eurasia and Africa revealed that haplogroup X is subdivided into two major branches, here defined as "X1" and "X2." The first is restricted to the populations of North and East Africa and the Near East, whereas X2 encompasses all X mtDNAs from Europe, western and Central Asia,Siberia, and the great majority of the Near East, as well as some North African samples. Subhaplogroup X1 diversity indicates an early coalescence time, whereas X2 has apparently undergone a more recent population expansion in Eurasia, most likely around or after the last glacial maximum."
http://www.usenet.com/newsgroups/sci.anthropology.paleo/msg05159.html

[js1138]

Evolution is occuring every minute, every hour and every day of every year all over the world. Let's take humans. Women have something called 'spontaneaous abortion' where the union of an egg and sperm is made and immediately aborted, many times even without the knowledge of the woman because of an anamoly.

Don't forget that the odds against a sperm cell are a hundred million to one in the swim competition. Overall, the chances of any particular individual surviving to reproduce are about a billion to one.

Just in case anyone tries to make that case that most mutations are detrimental.

[js1138]

I have always wondered if children born with Down's Syndrome are actually a throw back.

Throwback is a prescientific term, with not current meaning. There are many kinds of mutation, and chromosome copy errors are one. In plants, chromosome mutations are common and frequently lead to new species. This is rare, in animals, but it does happen.

All known human chromosome mutations are considered detrimental.

[js1138]

That's a cool graphic.

[blam]

"The Toba eruption 73,000 years ago induced both a crash in the global population and severed the Southeast Asian remnant from the ancestral African homeland."

There was an explosion of human 'branches' at this time and then again during/at the Last Global Maximum, 25-18,000 years ago. (Oppenheimer)

[blam]

"The chinese knew this already....the homo erectus branches in China were peopled with Shovel toothed specimens just like themselves....."

There are to types of the 'shovel' teeth, Sindont and Sundont(sp.). The Sindont is a branch off the Sundont family and are the Northern Asians and are characterized by flatter faces, the peculiar eye lid and lighter skin. My hunch is that this occurred in an isolated group in the north during the LGM.

[blam]

Here's an interesting article about Homo-Erectus in Georgia: Stranger In A New Land, that are 1.75 milliom year old. The Chinese claim to have Homo-Erectus skeletons (with tools) that are 2.25 million years old (unsubstanciated).

Now, I saw a program about the 'Hobbits' on Flores and they were speculating that they are Homo-Erectus however, they found 80k year old shell necklaces at the site. Homo-Erectus wasn't suppose to have the brain capacity for making necklaces.

Also, I've read that the brain size of Cro-Magnon Man was larger than modern humans. And, someone mentioned on another thread that Homo-Erectus and Neanderthal had larger brains too but, I suspect this is incorrect.

[CobaltBlue]

There are quite a number of groups who are willing to test your DNA for a fee, but the National Geographic program is the most reasonably priced that I've seen.

However, they aren't testing the maternal mitochondrial DNA in males, so if you are a male and want that done, you need to go elsewhere.

This program tests the (maternal female-to-female-to female, etc.) mitochondrial DNA in females, and the Y-chromosome (paternal male-to-male-to-male, etc.) DNA in males.

Females don't have Y-chromosome DNA but males do have mitochondrial DNA, which they get from their mother, not their father.

[AntiGuv]

Neanderthal had very slightly larger brain capacity; Homo erectus was definitely smaller (75%). I'm not sure about Cro-Magnon, although my impression was that they are all but indistinguishable from modern humans.

I don't dispute the 1.75 million year date (the oldest estimates of Homo erectus migration out of Africa is 1.8 million BC). I do doubt the 2.25 million year date, only because China is a marked distance from Africa and if Homo erectus had so expanded its range that early one would expect that it would be more readily apparent. However, I have no problem with the idea in the abstract. The Chinese are notorious for 'unsubstantiable' archeological claims..

As for the Flores 'hobbits' if they are what they appear to be from what little I know of them (a dwarf species typical of island fauna) then it seems they could very well be a pygmy erectus. Since the isolated population would've obviously experienced significant genetic change in any event, that may just as well include greater intelligence. That being said, I have no objection to the concept of Homo erectus necklace ability either.

PS. Cutest dwarf species of all: pygmy mammoth!

[CobaltBlue]

I don't think children with Down's syndrome could survive in the wild, even high functioning ones.

They don't have the survival instincts that animals have.

[wyattearp]

It would seem to me that the region with the most genetic variations is the go to region not the migrated out of region.

Thank you! Occasionally, somebody says something sensible in this "out of africa" nonsense.

[Drammach]

Thanks for that link..

I went to the Bradshaw Foundation homepage and found a link to the temples of Malta..
Older than the Egyptians..
And then they simply disappeared..

The site also provides an explanation for the "cart tracks" of Malta....