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Author Topic:   Human Chromosome 2 and the Evolution of Humans
jar
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Posts: 32152
From: Texas!!
Joined: 04-20-2004
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Message 7 of 56 (667913)
07-13-2012 3:57 PM
Reply to: Message 5 by NosyNed
07-13-2012 2:50 PM


Re: It happened again
Hi Ned, welcome home. Pull up a stump and set a spell.

I tried a thread about that just about a year ago that has a link to the article you may be looking for.

The 44 Chromosome man

Never generated much interest I fear.


Anyone so limited that they can only spell a word one way is severely handicapped!

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jar
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Posts: 32152
From: Texas!!
Joined: 04-20-2004
Member Rating: 2.2


Message 15 of 56 (668290)
07-19-2012 12:00 PM
Reply to: Message 14 by herebedragons
07-19-2012 11:29 AM


HBD writes:

The split would have to occur at the point where the populations diverge and interbreeding ends (there are nuances, but that's close enough). Did the chromosomal arrangement cause that? I don't think that there is a strong case that it did - and even if it did, it wouldn't happen immediately.

No, of course it wouldn't happen immediately. Is there a more plausible explanation for the break between humans and chimps? Chromosome 2 is presented as evidence of human - chimp evolution (and I agree it's quite a strong piece of evidence) but if it is not a plausible explanation for the evolution of chimp - human, doesn't that still leave us without a plausible explanation?

Remember that there most likely is no single cause of the split, but rather a whole host of unrelated events. Also many and probably the most important, may not be directly genetic changes in nature.


Anyone so limited that they can only spell a word one way is severely handicapped!

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jar
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Posts: 32152
From: Texas!!
Joined: 04-20-2004
Member Rating: 2.2


Message 20 of 56 (668366)
07-20-2012 10:47 AM
Reply to: Message 19 by herebedragons
07-20-2012 10:12 AM


on chromosome changes.
Several points that might help.

In Message 7 I provided a link to a thread from about a year ago where I posted a link to an article on the "The 44 Chromosome man" that does a great job of outlining the breeding possibilities he would face. It might help you.

Second, we can extract DNA from older remains (not fossils) that go back 20,000 or maybe even 60,000 years but not from fossils. As the age of remains increases the possibilities of recovering DNA decreases and the possibility of contamination increases. It becomes increasing difficult and unlikely to get results the further back we go and if the fusion even was in early hominids as it seems, we just won't find the evidence.

Third, the evidence we do have seems to show that early hominids expanded widely and in a series of waves and so populations were scattered and isolated.


Anyone so limited that they can only spell a word one way is severely handicapped!

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jar
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Posts: 32152
From: Texas!!
Joined: 04-20-2004
Member Rating: 2.2


(1)
Message 48 of 56 (671945)
08-31-2012 9:18 PM


Isolated populations
One thing that often gets overlooked is the fact that even in human populations, isolation was the norm and not the exception. During my lifetime I was lucky enough to get glimpses into such populations, in Appalachia, among the Amish and Mennonites in Pennsylvania, in the small islands along the Eastern Shore of the Chesapeake Bay, the Outer Banks and Coastal North Carolina, on Dafuskie Island and reservations in Arizona. Even in a city like Baltimore many folk were born, lived their lives and died within a few block area and married from within that population as had their parents and as would their children.

America was a land of small towns and travel outside was just something that didn't happen all that often. There were no interstates, air planes and trains were how the other folk got around. Cars were not all that reliable and every journey, even a day trip, was an adventure. To get from Baltimore to the Eastern Shore you either drove up to Delaware and down the coastal back roads or took a ferry across the Bay.

People married people that lived in their community. In many towns most everyone was related and second third and kissin cousin made sense.

In addition, infant mortality from all causes was higher than today.

In such settings marrying someone closely related would not be all that unusual and if you look at the charts in The 44 Chromosome Man you see that it is possible to have viable kids that pass on the trait. And it's those successes that count.


Anyone so limited that they can only spell a word one way is severely handicapped!

  
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