^ Why cant it be than slaves from Northern and Eastern Europe were more likely to end up in the Italian North, while slaves from the middle east were more common in the South specifically. This could be due to simple geography, you import the slaves that are closet to you, not from farther away. Not saying all slaves ended up in Italy, or in one place to that matter. Nor am I saying only Syrians were enslaved. Im saying maybe the slaves brought in were related to a geographical restriction.
But it this way. Most Italians live in Jew Jersey and New York. That does not mean I cannot find them in Wyoming, just that they are less able to make a genetic contribution.
Where is your proof that this happened? Was there some huge slave market in, say, Sicily, where all slaves from the east were sent?
By contrast, we have a lot of information, including carvings on major triumphal arches in Rome, as well as actual writings, that slaves taken in battle were brought to Rome and marched in the triumphal processions for the conquering general. You can go to the Arch of Titus and look at the depictions of all the Judean slaves. Or you can go and see the depictions of the Dacians, the Gauls, and on and on.
A certain number were executed, but the rest were sold by the general to slave traders. It's said that Caesar sold so many Gaulish slaves that there was a glut on the Roman market and they brought half the normal going rate. The slave traders then transported them to wherever in the Roman world there was a need for certain types of slaves: strong men for the mines, the galleys, or latifundia in various parts of the Roman world, pretty girls for the brothels. None of the preceding was likely to survive long enough to be manumitted and have offspring. People with specialized skills would be disposed of accordingly.
People were also sold into slavery, or sold themselves into slavery, including poor farmers in Italia, or captured by pirates, etc. Every town had a slave market and slave dealers. This was a business. They would send the slaves where they could get the best price, where they were needed. Or, if they had been captured in war, they in fact sent them as far away as feasible. Supposedly, many of my own Celt-Liguri were settled in Samnite country. You can see that distance didn't really pose a problem for the Romans. North Africans incorporated into the Roman military machine were sent to the Wall in Britain and stayed there for a long time. By your reasoning they should have been sent to Iberia. Balkan troops were also stationed there.
The immigrants who came to America in the late 19th/early 20th century didn't wind up along the eastern seaboard because it was closer to Europe. They wound up there because middle men hired by factory owners etc. had gone to small towns in Italy and persuaded people to sign up to go to America to work in the factories in the industrial belt in the east, or on the railroads, or, they themselves had heard about these jobs. Scandinavians made the much further trip out to the midwest because cheap land had been advertised to them. The Irish worked on the railroads for the same reason. There's an economic motive for most things if you know anything about history.
Your proposal is sheer speculation unsupported by any shred of data, and, indeed, contradicted by the data we do have. You can continue to pull it out of your hat for eternity, and I'm sure you will. It won't make it any more credible.
Nor, by the way, does this explain why there are similar percentages of Caucasian in Greece and southern Italy, and, in fact, southern Italians have less Caucasian, Mediterranean, and SW Asian than Greek Islanders. Were all the eastern slaves dumped there? The islands would have sunk under the weight. Nor was there that kind of need there.
Of course, should something come to light that proves differently, that's fine. What difference does it make? I just like my history as objectively interpreted as possible, not agenda driven.
Now, I'm tired of talking about it. I can't believe I got drawn into this dance once again.
