How much impact did slavery have on ancient gene pools in Europe ?

[Hauteville]

I really doubt that Roman Italy was like an old Brazil or Colombia. Sorry...

[Angela]

The case of African-American slaves can also help us estimate how frequent it was for slave masters to have children with their female slaves. I couldn't find much data on African-American Y-DNA. The Black Belt of Alabama DNA Project has over 400 members from all the former Confederate states, and among them only about 150 carry African Y-DNA (haplogroups A, B, E-M2). So this data suggests that over 60% of the African-American lineages are of European origin. That's huge considering, but relatively consistent with the 23andMe study (Bryc et al. 2014), which found that an average African-American has 24% of European DNA in his/her genome. Since Y-DNA only represents the paternal side, it is normal to find that the genome-wide impact is less than half. It would be exactly half looking at the first generation of hyrbids. But there is a good chance that these half-White slaves became freed more frequently (as was the case with Thomas Jefferson's children), prospered more in American society and consequently also left more descendant themselves with Black slaves, thus diluting their European genes again.

The highest figure for European origin yDna lines among African Americans I've ever seen is about 28%, with about 6-8% carrying European origin mtDna.

J.M. Lind et al, "Elevated male European and female African contributions to the genomes of African American individuals

Hum.Genet. 120 (2007), pp. 713-72 Abstract.

"The differential relative contribution of males and females from Africa and Europe to individual African American genomes is relevant to mapping genes utilizing admixture analysis. The assessment of ancestral population contributions to the four types of genomic DNA (autosomes, X and Y chromosomes, and mitochondrial) with their differing modes of inheritance is most easily addressed in males. A thorough evaluation of 93 African American males for 2,018 autosomal single nucleotide polymorphic (SNP) markers, 121 X chromosome SNPs, 10 Y chromosome haplogroups specified by SNPs, and six haplogroup defining mtDNA SNPs is presented. A distinct lack of correlation observed between the X chromosome and the autosomal admixture fractions supports separate treatment of these chromosomes in admixture-based gene mapping applications. The European genetic contributions were highest (and African lowest) for the Y chromosome (28.46%), followed by the autosomes (19.99%), then the X chromosome (12.11%), and the mtDNA (8.51%). The relative order of admixture fractions in the genomic compartments validates previous studies that suggested sex-biased gene flow with elevated European male and African female contributions. There is a threefold higher European male contribution compared with European females (Y chromosome vs. mtDNA) to the genomes of African American individuals meaning that admixture-based gene discovery will have the most power for the autosomes and will be more limited for X chromosome analysis. © Springer-Verlag 2006."
The study can be downloaded at researchgate. Samples were taken from four disparate American locations.

Sims et al found the exact same percentage (28%) for the non-E and non A/B yDna lines.
https://www.researchgate.net/profile...c5fd000000.pdf

There's a graphic of the breakdown.
Sims et al Y dna break down of African American men.jpg

This is obviously different from the situation in Latin America, where the majority of the y lineages are indeed West Eurasian, but that's because until recently most migration to the New World in those places was mostly male. Every situation is different and has its own dynamics.

Oh, the European female lines are estimated to have entered the gene pool during the early days when the African people were still treated more or less as indentured servants, and the best research on the subject I've seen speculates it involved female European indentured servants around the Virginia area where the first slaves were used.

[Tomenable]

I wonder how common was light hair (blond, red, light brown) in Ancient Greece.

It is well-known that in Greek mythology good deities and heroes are often light-haired.

But there were also blond historical figures, as well as blond evil villains from Greek mythology.

For example Lycus from Euripides's Heracles - a villain who usurped power in Thebes - was blond-haired:

"Were I but young and still a man of my hands, I would have seized my spear and dabbled those blonde locks of his with blood, so that the coward would now be flying from my prowes beyond the bounds of Atlas." - Amphitryon about Lycus

There are many pigmentation SNPs causing blond hair - for example rs12821256(C), rs1805005(T) and rs1393350(A).

Such and other SNPs responsibble for light pigmentation are present at high frequencies in ancient DNA samples from Indo-Iranian and some other steppe cultures such as Potapovka, Sintashta-Petrovka-Arkaim, Andronovo, Srubna, Tagar, Pazyryk, Tashtyk, etc.

Not just DNA shows this, but also mummies such as Ukok Princess from Pazyryk culture, or Xiaohe mummies, often have light hair.

According to one theory, Proto-Greeks split from Proto-Indo-Iranians, so their phenotypes could be similar:

https://en.wikipedia.org/wiki/Graeco-Aryan

[Tomenable]

Sims et al found the exact same percentage (28%) for the non-E and non A/B yDna lines.

Many African slaves transported to the Americas had Non-E/A/B already upon arrival, for example:

"Genome-wide ancestry of 17th-century enslaved Africans":

Full article here: http://www.pnas.org/content/112/12/3669.full

Supplementary info:

http://www.pnas.org/content/suppl/20...84112.sapp.pdf

The male slave was determined to belong to R1b-V88 haplogroup.

[Maciamo]

The highest figure for European origin yDna lines among African Americans I've ever seen is about 28%, with about 6-8% carrying European origin mtDna.

J.M. Lind et al, "Elevated male European and female African contributions to the genomes of African American individuals

Hum.Genet. 120 (2007), pp. 713-72 Abstract.

"The differential relative contribution of males and females from Africa and Europe to individual African American genomes is relevant to mapping genes utilizing admixture analysis. The assessment of ancestral population contributions to the four types of genomic DNA (autosomes, X and Y chromosomes, and mitochondrial) with their differing modes of inheritance is most easily addressed in males. A thorough evaluation of 93 African American males for 2,018 autosomal single nucleotide polymorphic (SNP) markers, 121 X chromosome SNPs, 10 Y chromosome haplogroups specified by SNPs, and six haplogroup defining mtDNA SNPs is presented. A distinct lack of correlation observed between the X chromosome and the autosomal admixture fractions supports separate treatment of these chromosomes in admixture-based gene mapping applications. The European genetic contributions were highest (and African lowest) for the Y chromosome (28.46%), followed by the autosomes (19.99%), then the X chromosome (12.11%), and the mtDNA (8.51%). The relative order of admixture fractions in the genomic compartments validates previous studies that suggested sex-biased gene flow with elevated European male and African female contributions. There is a threefold higher European male contribution compared with European females (Y chromosome vs. mtDNA) to the genomes of African American individuals meaning that admixture-based gene discovery will have the most power for the autosomes and will be more limited for X chromosome analysis. © Springer-Verlag 2006."
The study can be downloaded at researchgate. Samples were taken from four disparate American locations.

Sims et al found the exact same percentage (28%) for the non-E and non A/B yDna lines.
https://www.researchgate.net/profile...c5fd000000.pdf

There's a graphic of the breakdown.
Sims et al Y dna break down of African American men.jpg

This is obviously different from the situation in Latin America, where the majority of the y lineages are indeed West Eurasian, but that's because until recently most migration to the New World in those places was mostly male. Every situation is different and has its own dynamics.

Oh, the European female lines are estimated to have entered the gene pool during the early days when the African people were still treated more or less as indentured servants, and the best research on the subject I've seen speculates it involved female European indentured servants around the Virginia area where the first slaves were used.

This studies' sample sizes are tiny (93 and 118 African Americans in each study) and may not be representative. The best proof it is not representative is that, in the Sims et al. study, White Americans were found to have 25.5% of I1 (more than anywhere but Nordic countries) and 14.5% of R1a (higher than anywhere in Western Europe as far as east West Germany), which I think in much too high.

The Lind et al. study only tests Y-haplogroups E, F, I and R, so they don't distinguish between European E1b1b and other (African) subclades of E. Likewise they only test mtDNA L, M and N and assume that M and N are European, even though M isn't found in Europe and N includes subclades found in West Africa (H1, J1b1a, U5, U6, V) as well as Europe. So they overestimate European mtDNA.

Anyway you can't have only 28% of European Y-DNA in African Americans if 24% of their autosomal genes of of European origin (as the 23andMe study found, with a sample size of 5,269 African Americans). Y-DNA should be about twice higher than autosomal genes as European mtDNA is negligible in African Americans.

[Yetos]

@ Greying Wanderer

well the fertility rates, yes,
I wonder are they rates from inside family, or general rates,
more clear, prosper family has 2,4 or just a prosper man?

now lets see some other factors, factors about death,
1) honour crimes,
2) political enemies,

1) honour crimes,
there are 2 kinds of step brothers from same father, they are all legal, they are legal and bastards,
at the second case even today we have crimes due to honour,
A roman wife to protect her children, if found something, surely she would act like a devil to kill the 'intruder' at family,
and believe me, volunteers could be many, for a few denarii,
and what when the bastard grows old and strong? does he plan to revenge his 'brothers' and the father he never knew? possible yes, and many made that a plan for a life,
'Honor' is something, and a bastard dream to restore mother pride,

2) the political enemies,
hm just consider 2 senate men, a patrician and a pleveian, and one of them, holds by hand a young man, and say the other,<<this is your son, with your slave Xyz>>
or see your bastard grow among your enemies?
many politicians from that era search for such things, and pay good money for such, and slaves are always untrustable, cause as easily you buy them, same easily they can sell you,

so my point at this post, is that a bastard could also destroy a noble family, and death has one more reason to come, that might not had at poor families,

Romans knew that,

[Tomenable]

This studies' sample sizes are tiny (93 and 118 African Americans in each study) and may not be representative. The best proof it is not representative is that, in the Sims et al. study, White Americans were found to have 25.5% of I1 (more than anywhere but Nordic countries) and 14.5% of R1a (higher than anywhere in Western Europe as far as east West Germany), which I think in much too high.

The Lind et al. study only tests Y-haplogroups E, F, I and R, so they don't distinguish between European E1b1b and other (African) subclades of E. Likewise they only test mtDNA L, M and N and assume that M and N are European, even though M isn't found in Europe and N includes subclades found in West Africa (H1, J1b1a, U5, U6, V) as well as Europe. So they overestimate European mtDNA.

Anyway you can't have only 28% of European Y-DNA in African Americans if 24% of their autosomal genes of of European origin (as the 23andMe study found, with a sample size of 5,269 African Americans). Y-DNA should be about twice higher than autosomal genes as European mtDNA is negligible in African Americans.

Hammer et. al. 2005 had a large sample of 651 African-American Y-DNA haplogroups:

https://www.familytreedna.com/pdf/HammerFSIinpress.pdf

E --------------------- 69,7%
B --------------------- 2,3%
A --------------------- 1,4%
R1b-V88 ------------- 0,5%
J ---------------------- 0,8%
O --------------------- 0,3%
K --------------------- 0,3%
P --------------------- 0,3%
Q --------------------- 0,2%
G --------------------- 0,9%
I ---------------------- 5,3%
R1a ------------------ 1,1%
R1b-M269 ---------- 17,3%

Detailed territorial origin of those 651 African-American samples within the USA:

Arizona-Phoenix (AZ1) ---- 76
Arizona-Mesa (AZ2) ------- 52
Connecticut (CT) ----------- 89
Florida (FL) ----------------- 20
North Carolina (NC) ------- 84
New York City (NYC) ------ 42
Ohio (OH) ------------------ 103
South Dakota (SD) -------- 57
Virginia (VA) ---------------- 77
Vermont (VT) -------------- 51

[Tomenable]

in the Sims et al. study, White Americans were found to have 25.5% of I1 and 14.5% of R1a

Hammer et al. 2005 found European-Americans to have just 11.7% of I1 and just 7.2% of R1a.

However, I think that these are too low frequencies. The reality must be somewhere in between.

There are differences between ancestry groups. For example Polish-Americans have lots of R1a.

============

Hammer 2005 sample of European-American males was not proportional to state population.

For example 20.5% of his Whites were from Vermont, which has just 0.2% of U.S. population.

We need a sample that is proportional to population size of states and of ancestry groups.

[Tomenable]

Here is a breakdown of African-American E from Hammer et al. 2005:

E-P1 --------------------- 62,0%
E-SRY4064* ------------- 5,1%
E-P2* -------------------- 0,6%
E-M35* ------------------ 0,9%
E-M78 ------------------- 1,1%

Total of haplogroup E - 69,7%

[Angela]

This is another study with about 500 samples, and again shows about a 30% West Eurasian yDna level.

http://www.plosone.org/article/fetch...esentation=PDF

I think the relationship to autosomal dna is a complicated issue partly because there's a lot of substructure in the African-American community. Much of this traces back to the old "class" distinctions between the minority group of "house slaves" versus the "field slaves" who were the majority of the population. That 20% figure for European autosomal dna is just an average. There are African-Americans with very low levels of European ancestry (Oprah Winfrey is one example) and self-defined African Americans who are much more than 50% European.

This is why I think it's hard to draw parallels between slave societies that are 2000 years apart and in very different cultures. There are even differences between the North American versus South American slave societies. In South America there just weren't all that many European women ever, and low numbers of Europeans in total, so virtually everyone has Amerindian and SSA mtdna.

[Greying Wanderer]

I use the same logic to justify that male masters had a lot of children with female slaves, because they could afford to take care of the children. The richer a Roman citizen was, the more household slaves he usually had, and the more illegitimate children with them.

Yes. I think what you say is possible but it requires the fathers putting their slave-descended offspring into the middle class somehow.

edit: by middle class i mean farmers and artisans

[bicicleur]

Yes. I think what you say is possible but it requires the fathers putting their slave-descended offspring into the middle class somehow.

edit: by middle class i mean farmers and artisans

even legitimate children were considered property of the father

he could do with them as he pleased

[Tomenable]

Sims et al. in her sample of 125 has proportions of U106 to P312 like 33:67 (19:39).

In the American centric FTDNA R1b project these proportions are 28:72 (897:2352):

http://www.anthrogenica.com/showthre...l=1#post119363

[Greying Wanderer]

even legitimate children were considered property of the father

he could do with them as he pleased

sure, my point is did they end up in the middle class or among the poor because it's their and their descendant's future TFR over generations that would decide the percentage among the modern population

For example if Rome in 500 AD had
- 10% mostly Roman descent upper class
- 30% mostly Roman descent middle class (farmers and artisans)
- 60% mostly non-Roman slave descent lower class

then in 1000 AD the percentages might be
- 10% mostly Roman descent upper class
- 30% mostly Roman descent middle class (farmers and artisans)
- 30% mostly Roman descent lower class
- 30% mostly non-Roman slave descent lower class

due to different TFR by class and
- excess upper class drop into the middle class
- excess middle class drop into the lower class

on the other hand if it was standard practice for them to set their slave kids up in the middle class then the impact would be much greater (which happened in the Caribbean a lot but I don't know about other times and places)

[Angela]

sure, my point is did they end up in the middle class or among the poor because it's their and their descendant's future TFR over generations that would decide the percentage among the modern population

For example if Rome in 500 AD had
- 10% mostly Roman descent upper class
- 30% mostly Roman descent middle class (farmers and artisans)
- 60% mostly non-Roman slave descent lower class

then in 1000 AD the percentages might be
- 10% mostly Roman descent upper class
- 30% mostly Roman descent middle class (farmers and artisans)
- 30% mostly Roman descent lower class
- 30% mostly non-Roman slave descent lower class

due to different TFR by class and
- excess upper class drop into the middle class
- excess middle class drop into the lower class

on the other hand if it was standard practice for them to set their slave kids up in the middle class then the impact would be much greater (which happened in the Caribbean a lot but I don't know about other times and places)

I've never seen any proposed figure of 60% for the slave population. In fact, the highest percentage I've ever seen is about 35%. Then lower that percentage by all the slaves in mines, galleys and being worked to death on the latifundia who either weren't procreating at all, or died before they'd have very many offspring. Then take out the female prostitutes, since from the mass graves of aborted fetuses and newborns that have been found it seems that rearing the children produced by prostitutes wasn't part of the economic equation.

Of the remaining percentage, consisting of female house slaves who bore children to their masters and more skilled male slaves who might be manumitted later on in life, what happened to those offspring? I think some might have indeed made it into the middle classes, but were all masters so benign? Thomas Jefferson had numerous slave children with Sally Hennings, some of whom were white enough to "pass". Estimates are that they were either quadroons or octoroons. Yet he didn't free them or help them during his lifetime. All he did for them was not set the dogs on them when they ran away. He did free the two still at Monticello when he died, but not their cousins, aunts etc. They had trades, but I don't remember any indication that anything was left to them. There are reports of some who sent their children north or left them some land, but many slave masters happily even sold their offspring south into the sugar cane fields if we are to believe the many slave narratives.

Things were a bit different in New Orleans with the French settlers, and in the Caribbean. Alexandre Dumas père was the grandson of a French landowner and an African slave woman in Haiti. The son of the union was taken to France, educated, and became a general. The other children weren't treated in the same way. They were sold to another plantation owner in Haiti, along with the mother. Was it because he was male, because he was unusually bright and talented? Those are only guesses. So, I don't know how one would calculate percentages.
https://en.wikipedia.org/wiki/Alexandre_Dumas

When looking at the genetics things get even more complicated. In the Republican era, many of the people who were enslaved were other inhabitants of the Italian peninsula and islands, so how would one distinguish them genetically from the "free" population? As I've said before, how similar might the Italics of Cis-Padania have been to the hundreds of thousands of Gaulish slaves taken by Caesar? There were probably differences, but how easy would it be to distinguish them from one another? How different would the Greek slaves have been from the "locals", especially from the more southern areas, given there had already been Greek colonization in at least the coastal zones? Were the Illyrians and the Messapi all that different from one another? I don't know. Even when going further afield, slaves from Anatolia or Syria, from a period before the Muslim invasions and the slave trade from East Africa and West Africa, would have had a lot of Anatolian Neolithic in them and have carried the uniparental markers to match.




I'm not saying there's no way of figuring it out; I'm just saying it's going to take a lot of resolution of uniparental subclades, as was done in that fine mtDna U6 paper, and lots and lots of ancient dna from very specific contexts, and even then we're not going to know how that translates precisely into autosomal percentages.

http://bmcevolbiol.biomedcentral.com...71-2148-14-109

[Greying Wanderer]

@Angel

I've never seen any proposed figure of 60% for the slave population. In fact, the highest percentage I've ever seen is about 35%.

Sure, I was just illustrating that even if the percentage was huge at the time then if they mostly stayed in the lower class segment the percentage may have declined greatly over centuries.

(assuming there was differential TFR by class)

[Angela]

[COLOR=#333333]@Angel



Sure, I was just illustrating that even if the percentage was huge at the time then if they mostly stayed in the lower class segment the percentage may have declined greatly over centuries.

(assuming there was differential TFR by class)

Oh, ok, got it. Good point.

It's all really complicated, because we have to do so much speculation. I guess my main point is that even with aDna it may be hard to unravel the genetics once you move into the Late Bronze Age or Iron Age and you have the intrusion of populations which are themselves admixtures (in different proportions) of older populations.

[MOESAN]

This is another study with about 500 samples, and again shows about a 30% West Eurasian yDna level.

http://www.plosone.org/article/fetch...esentation=PDF

I think the relationship to autosomal dna is a complicated issue partly because there's a lot of substructure in the African-American community. Much of this traces back to the old "class" distinctions between the minority group of "house slaves" versus the "field slaves" who were the majority of the population. That 20% figure for European autosomal dna is just an average. There are African-Americans with very low levels of European ancestry (Oprah Winfrey is one example) and self-defined African Americans who are much more than 50% European.

This is why I think it's hard to draw parallels between slave societies that are 2000 years apart and in very different cultures. There are even differences between the North American versus South American slave societies. In South America there just weren't all that many European women ever, and low numbers of Europeans in total, so virtually everyone has Amerindian and SSA mtdna.

Agree for the most, but every South-American country has its global and regional historIES; we cannot compare Argentina or Uruguay to Peru or Bolivia.
Concerning the Y haplos of European origin in the USA, we have to keep in mind the weight of the diverse countries of origin of immigrants has dramatically changed over time; the British-Irish-German-Scandinavian Yankee of the first times is loosing weight today; You have only to look at the marines and at the second hand movies series actors and actresses. The wheel is turning on.

[Ailchu]

Additionally there is now ample evidence that the Romans liked to acquire beautiful female slaves (especially exotic blondes and redheads) for the purpose of sex, and that they often had children with them. These children were typically freed once their reached adolescence or adulthood. In fact, most of the freed slaves in ancient Rome could have been the offspring of Roman patricians with their slaves.

there are several roman sources which glorify barbaric women so this thaught is not far away but is there actual evidence for this?

[Jovialis]

It has been argued that slaves didn't procreate much as they weren't free. But that's nonsense. Slaves were valuable commodities, sold on markets. If you owned slaves, having them breed together created more wealth. So the more children they had the better. Additionally there is now ample evidence that the Romans liked to acquire beautiful female slaves (especially exotic blondes and redheads) for the purpose of sex, and that they often had children with them. These children were typically freed once their reached adolescence or adulthood. In fact, most of the freed slaves in ancient Rome could have been the offspring of Roman patricians with their slaves.

Perhaps this is a reason for my mtdna H6a1b ending up in Italy, and account for some of the northern European autosomal admixture.

http://www.eupedia.com/europe/Haplogroup_H_mtDNA.shtml


H6 was absent from Europe before the Bronze Age and has such a wide distribution across the continent nowadays that it would likely have been spread both by R1a and R1b branches of the Indo-Europeans. Indeed, H6 was found in ancient remains from most Indo-European Bronze Age cultures, including Yamna (H6a1b), Corded Ware (H6a1a), Unetice (H6a1b, H6a1b3), Poltavka (H6a2), Okunevo (H6a1b), Srubnaya (H6a1a) and Andronovo (H6). Actually H6 was the only H samples identified so far in the Andronovo culture in Central Asia.

[Fire Haired14]

Additionally there is now ample evidence that the Romans liked to acquire beautiful female slaves (especially exotic blondes and redheads) for the purpose of sex, and that they often had children with them. These children were typically freed once their reached adolescence or adulthood. In fact, most of the freed slaves in ancient Rome could have been the offspring of Roman patricians with their slaves.

Are you able to provide that evidence? Evidence that acquiring female slaves for sex, especially northern European ones, was popular. And that the children usually were freed?

Of course we need lots of ancient DNA from Italy to know for sure, but if the north Euro-like ancestry in Italy is all recent(Celtic, German, Slaves) then that would probably mean Romans and early Iron age Italians were an intermediate between Sicilians and Sardinians. And if most north Euro-like ancestry in Balkans is recent(Slavs) that would mean ancient Greeks and Ilyrrians were like Greek Islanders. I'm just throwing that at out there.

[ThirdTerm]

The presence of Africans in Britain has been recorded since Roman times, but has left no apparent genetic trace among modern inhabitants. Y chromosomes belonging to the deepest-rooting clade of the Y phylogeny, haplogroup (hg) A, are regarded as African-specific, and no examples have been reported from Britain or elsewhere in Western Europe. We describe the presence of an hgA1 chromosome in an indigenous British male; comparison with African examples suggests a Western African origin. Seven out of 18 men carrying the same rare east-Yorkshire surname as the original male also carry hgA1 chromosomes, and documentary research resolves them into two genealogies with most-recent-common-ancestors living in Yorkshire in the late 18th century. Analysis using 77 Y-short tandem repeats (STRs) is consistent with coalescence a few generations earlier. Our findings represent the first genetic evidence of Africans among 'indigenous' British, and emphasize the complexity of human migration history as well as the pitfalls of assigning geographical origin from Y-chromosomal haplotypes.
http://www.nature.com/ejhg/journal/v.../5201771a.html

This 2007 study identified British men who carry Y-DNA haplogroup A1 that closely matches the one identified in men presently living in West Africa, which suggests that their black ancestor arrived in Britain within the past few thousand years. A1 possibly entered the gene pool in northern England 1800 years ago when Africans were brought into the region by the Roman Empire. These men have the Yorkshire surname and a typical European appearance, indicating that Africans were fully integrated in ancient British society.

[bicicleur]

This 2007 study identified British men who carry Y-DNA haplogroup A1 that closely matches the one identified in men presently living in West Africa, which suggests that their black ancestor arrived in Britain within the past few thousand years. A1 possibly entered the gene pool in northern England 1800 years ago when Africans were brought into the region by the Roman Empire. These men have the Yorkshire surname and a typical European appearance, indicating that Africans were fully integrated in ancient British society.

the same goes for a British male with an African subclade of R1b-V88.
his British line goes back to the 17th century

[Dianatomia]

I think Ancient Greece and Ancient Rome were different regarding the slaves. Greece was a microcosmos, where slaves usually were fellow Greeks or people from adjecent areas who ended up being slaves for any particular reason. Usually war booty. Slaves were part of Ancient Greek society, except for politics. In Athens for example, if you were a slave from Thebes, you were not an Athenian and not an equal citizen. But you were able to hold important positions. Even political advisers, artisans, etc. The Parthenon has been build by hands of slaves as well as free men. Though usually slaves were used for agriculture. Taking everything into account though, it is kind of a on oxymoron to argue what percentage of the Greek gene pool was from slaves. Since the gene pool might have been similar. One has to prove that slaves were different from free men to begin with. There is no evidence I have seen for this. Someone argued that there must be a difference between Mycenean Greeks and Classical Greeks (since Mycenean Greeks had slaves), but all evidence so far points to the fact that Mycenean Greeks are similar to classical Greeks. There is some evidence that there have been some changes between Bronze Age Greece and Mycenean Greece though. This is probably due to the arrival of the proto-hellenes. Lastly, there were certainly non-Greek slaves in Hellenistic Greece. But there is no evidence that these slaves were imported to Greece in serious numbers. I.e. a Greek from Alexandria, Egypt could hold a slave of any origin, but this hardly has any impact on the gene pool of the people of Greece.

Ironically, many Greeks were Roman slaves during the Roman empire. The Roman empire was somewhat different compared to Ancient Greece. Many slaves were imported from other parts of 'mostly' Europe. Yet, by far the largest percentage of slaves was from local Italian peoples. However, due to Rome's imperial nature, it is undeniable that a larger variety of people were imported into Italy than in Greece for example.

[Dianatomia]

And if most north Euro-like ancestry in Balkans is recent(Slavs) that would mean ancient Greeks and Ilyrrians were like Greek Islanders. I'm just throwing that at out there.

I don't buy that. Logically Indo-Eurpeans settled in mainland Greece, mixed with locals, then also migrated to islands, then to Asia Minor. The rule is that the North Euro like ancestry is deluded in every step. So the Ancient Greek islanders would have had less north Euro ancestry than the Ancient Greek mainlanders to begin with.