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Deriving the age of CT from Archaeological Records
Topic Started: Apr 10 2008, 11:35:18 PM (597 Views)
Ibra
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Hammer et al
 
The time to the most recent common ancestral Y chromosome
and the estimated ages of 11 major clades are presented in Table
2. To provide estimates of the age of the nodes, we chose to fix
the time to the most recent common ancestor of CT (defined by
P9.1, M168, and M294) at 70 thousand years ago (Kya)
, which is
consistent with previous estimates from genetic and archaeological
data (Lahr and Foley 1998; Hammer and Zegura 2002; Macaulay
et al. 2005), and is the chronological approximation given
in Jobling et al. (2004) (p250) for the first major human out-of-
Africa dispersals.



Hammer et al
 
We estimated the times for intermediate nodes
by using a linear interpolation. The age estimates in years should
be viewed with caution because we do not know if the calibration
date chosen above is accurate.


Posted Image

This is interesting because the length of any branch is measured against CT and in the case that CT really isn’t really 70,000 years B.P. the data can be linearly calibrated to re estimate the age. For example if it was found that that CT was really 77,000 years B.P. ;) , then we take the old ages of each haplogroup and multiply them by (77,000/70,000)=(1.1).

Some reasons why CT might be 77,000 years or older.


http://www.svf.uib.no/sfu/blombos/Artefact_Review1.html

http://www.sciencemag.org/cgi/content/abstract/295/5558/1278

http://www.sciencemag.org/cgi/content/abstract/317/5834/114

http://www.sciencemag.org/content/vol317/i...317_114_F3.jpeg

CT has to be at least 77,000 years at the time of the South African MSA and Homo sapiens entry into South Asia.

Topic split from "Aurignacian, the E clan and Neadrathals"
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ren
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I'd say CF was an initial coastal expansion. Later, bands expanded inlands into the Middle East/Europe/North Africa and Central Asia. Small number might have eliminated lineage diversity © or C was never part of the expansion in the first place.
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manju
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ren
Apr 19 2008, 01:48 AM
I'd say CF was an initial coastal expansion. Later, bands expanded inlands into the Middle East/Europe/North Africa and Central Asia. Small number might have eliminated lineage diversity © or C was never part of the expansion in the first place.

As of now, I have observed only one Indian tribe with C*, F and H combination. Though it should be noted here that study is old (Cordaux et al. 2004) and at that time none of these were tested for M356(C5).

But Sengupta et al. 2005/2006 still observed C*(M216/RPSAY) among two Dravidian groups and one Dai group in China.



DYS19- DYS388- DYS389AB- DYS389CD- DYS390- DYS391- DYS392- DYS393- DYS439- DYSA7.2
15 13 17 14 24 10 11 13 12 10 (Pallan - caste)
17 13 16 13 25 9 11 14 13 10 (Toda - tribe)
14 13 16 12 21 10 11 12 11 11 (Dai - East China)

If you observe Dravidian tribes then the pattern would be (F,H) + other haplogroups.

Koya Dora/Konda Reddy - F, H, O2a
Kurumba - F, H, R2, L1
Kamar - F, H, L1, O2a
Yerava - F, H, C*, R1a1

Curiously, other two groups with C* like Pallan and Toda have R1a1. Parsimoniously speaking C* appears to be associated with R1a1 than F and H.
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Ibra
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As I’ve said before the coalescence of haplogroups in this study are dependent on the age of CT and can be linearly calibrated. The authors chose (not calculated) the age of CT to be 70 kyr; however I will attempt to derive the age of CT from their own data by squeezing it between two archaeological bounds which are the pre-Toba archaeological layer and entry of moderns into Anatolia/Australia (46kyr at most). But first I’ll define the age of CT at x (unknown) and use the calibration equation below.

new age = (x/70)*old age

1. DE arose in Africa was implanted into Eurasia by the humans who had just reached India from Africa by 77 kyr. DE must be older than the pre-Toba assemblage.

Translation:

(x/70)*65 > 77

Therefore: (x > 82.92 kyr)


2. IJ likely arose in Anatolia, the crossroads between Europe and the Middle East. IJ couldn’t be older than 46kyr, which coincides with the entry of Eurasians to Europe and Australia.

Translation:

(x/70)*38.5 < 46

Therefore: (x<83.64)

Therefore: (82.92<x<83.64)

That’s a tight bound! Let’s just say the age of CT is 83kys.
B)
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manju
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What if you make the assumption that DE reached South Asia around 77000 BP and responsible for MSA artifacts (Jwalapura). Let's consider D in Andamanese and YAP in Koraga tribe representative of that migration. Let's make the entry of F clan around 45000 BP (entry of sophisticated tools by Petraglia et al.). What would be CT age making these assumptions?
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Ibra
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manju
 
What if you make the assumption that DE reached South Asia around 77000 BP and responsible for MSA artifacts (Jwalapura). Let's consider D in Andamanese and YAP in Koraga tribe representative of that migration. Let's make the entry of F clan around 45000 BP (entry of sophisticated tools by Petraglia et al.). What would be CT age making these assumptions?


If we do this then we get a contradiction. (CT > 82.92 kyr) and (CT < 66 kyr). The problem is in the assumption that F is significantly younger than the 45000 BP stone tool industries, which it’s probably not.

If we do the example again with P (P is specific to some regions and evolved after the Eurasian expansion 46kyr) then:

82.92<CT<95.71

CT would be in there but we would not know which value. By chance I was able to find two haplogroups (DE and IJ) with archeological significance such that CT was squeezed between 1 integer value. The implication for all this is that the haplogroup in the above table are older by a factor of 83/70=1.18571.


Adjusted Age (kyr):

CT:-----83.0
CF:-----81.7
DE:-----77.1
E:-------62.3
E1b1:--56.3
F:-------56.9
IJ:------45.7
I:-------26.3
K:------ 56.2
P:------ 40.3
R:------ 31.8
R1:-----21.9

Thanks Maju :)
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Ibra
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I’d like to show that CT=83 kyr is very much consistant with the most recent mtDNA estimation (Behar et al.) The immediate ancestor of L3 is L3'4. L3'4 is estimated to be 94.3 kyr, and L3 is estimated to be 76 kyr. We may assume a population belonging to L3’4 and BT broke from a general African population and were isolated in Ethiopia during the interval [94, 76] kyr. The appearance of CT corresponds to the first 11 kyr in that interval and the remaining 7 kyr is in accordance with the early emergence of CF and the late emergence of DE. Immediately after the emergence of DE/CF + L3, that African population crossed the “Gate of Tears” and made their way to Asia. Subsequent Eurasian history begins with a big bang. :unsure:
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