Friday, November 5, 2010

Tuscans, Guess Two

An Ancient Phoenician Coin

In the previous post, we guessed at some Fertile Crescent contribution to modern Tuscans, based on the examination of Dienekes' k=10 ADMIXTURE data, which indicates that a Fertile Crescent signature is buried in the mix of population components that make up Modern Tuscans.

As a first guess, we took a stab at Cypriots as the source for the Fertile Crescent contribution to Tuscans.

Because the Fertile Crescent Signature is buried in other similar populations, it's not clear exactly which Fertile Crescent population contributed to the Tuscan gene pool.  So we'll take another guess at who the intrepid Mediterranean seafarers might have been.

This time, we'll guess Syrians.  That's a good guess, as Syrians are an intermediate population in the Fertile Crescent.  Their Fertile Crescent genetic signature is similar to neighboring Jordanians.  In addition, their proximity to Lebanon would hint that the Syrian Fertile Crescent composition might be a close match to those mythical seafarers, the Phoenicians.

We follow the same process as in the previous post.  First, we assume that all of the Southwest Asian component comes from the "Syrian" contribution.  Syrians have a 32.4% Southwest Asian component, while Tuscans have a 7.7% Southwest Asian Tuscan Component, so we estimate that the Syrian contribution to the Tuscan gene pool is 7.7/32.4 = 23.76%.

Again, we set up a series of guesses for the "Mystery Composite", the contribution to the Tuscan gene pool that is not from the Fertile Crescent.  These are shown in the table, below:

Table of Population Subcomponents 1 to 10,
Guesses for “Mystery Composite”
Adjusted for “Syrian” Fertile Crescent Contribution

1=WA
2=NWA
3=SE
4=NEA
5=SWA
6=EA
7=NE
8=WA
9=EA
10=SA











1
0.20
0
0.5
0
0
0
0.30
0
0
0
2
0.18
0
0.5
0
0
0
0.32
0
0
0
3
0.16
0
0.5
0
0
0
0.34
0
0
0
4
0.20
0
0.55
0
0
0
0.25
0
0
0
5
0.18
0
0.55
0
0
0
0.27
0
0
0
6
0.16
0
0.55
0
0
0
0.29
0
0
0

We plot Tuscans against 0.2376 Syrians + 0.7623 Mystery Composites(six guesses from table above):
Again, Tuscans are represented on the left of each bar set.  The result of the 0.2376 Syrians combined with  guesses 1 through six for the Mystery Composite are shown on the right bar in the six bar sets.  It should be noted that I have slightly renormalized the Syrian result, based on the observation that there is no observable South Asian, East African or West African contribution to Tuscans.  You can see these minor components on the top of the right bars.  If Syrians or perhaps Phoenicians did contribute to the Tuscan gene pool, the group that did lacked these components.  Alternatively, it is possible that the samples chosen for Tuscans somehow miss these minor components.

Examining the table, it is guess two that most closely approximates Modern Tuscans.  With Syrians as the Fertile Crescent contributor, Mystery's best guess is described by a ten component vector, as in Dienekes' table for the k=10 run:

[0.18    0     0.5   0       0     0     0.32    0     0     0]

18% West Asian, 50% Southern European and 32% Northern European.

It's notable that this result isn't very different than the last result.  With a part Syrian origin for Tuscans, rather than a part Cypriot origin,  "Mystery" has only slightly more West Asian and slightly less Northern European, but the results are similar.

Next, we'll look at a part Anatolian origin for Tuscans.
 

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