Re : Jarus vs J. Richards on Northern Italy

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Re : Jarus vs J. Richards on Northern Italy

Post  Arch Hades on Tue Mar 05, 2013 9:40 pm

http://majorityrights.com/weblog/comments/893/

J : Richards writes
"Yes, the Renaissance began in Italy, but it was in Northern Italy, among the Germanic Lombards, who occupied the region after migrating from Germany; the darker people of Southern Italy were not behind the Renaissance."

"Regarding the Northern Italian issue, Dienekes has read too much into one study of haplogroup I and ignored a great deal of evidence showing notable differences between Northern and Southern Italians, and the significant Northern European character of Northern Italians:"


Well I don't know what Dienekes wrote but anyway to prove this J. Richards writes.

"The prevalence of the c282Y mutation is much higher in Northern Europeans and Northern Italians compared to Southern Italians and Middle Eastern populations, and this mutation has a similar prevalence among Northern Europeans and Northern Italians:"

SOURCE : Salvioni A, Mariani R, Oberkanins C, Moritz A, Mauri V, Pelucchi S, Riva A, Arosio C, Cerutti P, Piperno A. Prevalence of C282Y and E168X HFE mutations in an Italian population of Northern European ancestry. Haematologica. 2003 Mar;88(3):250-5.

http://www.ncbi.nlm.nih.gov/pubmed/12651261


Well first off the very study itself claims the high frequency of this gene in the sampled Northwest Italian population is because of Celtic influence, not Germanic influence

Abstract
BACKGROUND AND OBJECTIVES:

"In Italy, the prevalence of C282Y is lower than in Northern European countries. We hypothesized a higher prevalence of C282Y in Northern than in Southern Italian populations. We previously identified a nonsense mutation (E168X) in hemochromatosis probands originating from a region in the north-west of Italy. We aimed to define the prevalence of C282Y and E168X in that region and the origin of the E168X mutation by haplotype analysis.
DESIGN AND METHODS:

Six-hundred and six blood donors were investigated for C282Y, H63D, S65C and E168X mutations by polymerase chain reaction (PCR)-restriction assays. Three hundred were also tested for rare HFE and TFR2 mutations by reverse-hybridization test strips. D6S265, D6S105 and D6S1281 microsatellites were analyzed to define E168X 6p-associated haplotypes.
RESULTS:

One C282Y homozygote, thirteen C282Y/ H63D compound heterozygotes, four E168X heterozygotes and three E168X/H63D compound heterozygotes were found. The allele frequencies of C282Y, H63D, S65C, and E168X were 4.7%, 14.9%, 0.74% and 0.58%, respectively.
INTERPRETATION AND CONCLUSIONS:

The prevalence of C282Y in the region investigated was much higher than that previously reported in Italy. This finding is probably due to the heavy Celtic component of this north-western population and suggests that in populations of Northern Italian descent screening studies for hemochromatosis could be cost-effective. The prevalence of E168X in this region, although low, suggests that the mutation probably originated here many years ago and its frequency increased as a result of a local founder effect. Given its severity, we suggest that the E168X mutation should be searched for in all hemochromatosis patients of Northern ancestry with an incomplete HFE genotype."

So that this gene was brought in by Germanic Lombards is incorrect, secondly it's a just a single marker. You can't make over all genetic affinity statements based on single genes or diseases or anything like that. It requires large scale genome sequencing to get an idea of overall population structure and affinity.


He uses another similar study on a blood disorder to try and prove this too

SOURCE : Candore G, Mantovani V, Balistreri CR, Lio D, Colonna-Romano G, Cerreta V, Carru C, Deiana L, Pes G, Menardi G, Perotti L, Miotti V, Bevilacqua E, Amoroso A, Caruso C. Frequency of the HFE gene mutations in five Italian populations. Blood Cells Mol Dis. 2002 Nov-Dec;29(3):267-73.

http://www.ncbi.nlm.nih.gov/pubmed/12547216


Once again this study implies a Celtic orgin of the disease in Italy, not a "Germanic" one. Secondly there's not even much consistency, like this "S65C mutation" is found in Emilia-Romagna but not in Piedmont? Pietmontese should be a bit more Northern influenced than Emilia-Romagna obviously.


Abstract

Genetic hemochromatosis is an autosomal recessive disorder characterized by iron overload and a variety of clinical manifestations such as liver cirrhosis and arthropathy. It is the most common genetic disease of northern European populations. The principal gene responsible for hereditary hemochromatosis, designated HFE, is located on chromosome 6 in the HLA region. The single point mutation 845A, changing cysteine at position 282 to tyrosine (C282Y), in this gene has been identified as the main genetic basis of hereditary hemochromatosis. Two other mutations, 187G, a histidine to aspartate at amino acid 63 (H63D), and 193T, a serine to cysteine at amino acid 65 (S65C), appear to be associated with milder forms of hereditary hemochromatosis. There is a high prevalence of the C282Y mutation in northern European populations, whereas in those of the Mediterranean basin the prevalence seems low and almost absent in Far East countries. This mutation seems usually to occur on the ancestral haplotype 7.1. Accordingly, a Celtic origin of this mutation has been suggested. The aim of this study was to determine the frequency of HFE gene mutations in five geographic regions in Italy. Samples were tested for C282Y, H63D, and S65C mutations of the HFE gene according to methods of each laboratory and the results were standardized with the exchange of typed samples between the different laboratories. In addition, C282Y-positive DNA samples were typed for D6S105 allele 8 and HLA-A3 by ARMS-PCR. We have found that the allele frequency of the C282Y mutation decreases from northeast Italy (Friuli, 6%) to northwest Italy (Piedmont, 4.8%) and to central Italy (Emilia-Romagna, 1.7%). However, this mutation is lacking in the two regions of the Mediterranean basin's center (Sicily and Sardinia). Accordingly, a significant difference in the frequency of the mutation was observed between these Italian regions (P = 0.07 x 10(-3)). In contrast, no difference was observed in allele frequency of H63D in the five Italian regions. Finally, as regards the S65C mutation a very low frequency was observed in Friuli, Emilia-Romagna, and Sardinia, whereas in Sicily and Piedmont we have not found this mutation. In conclusion, these data are consistent with the hypothesis that the C282Y mutation occurred in Caucasian populations of Celtic origin, whereas the H63D mutation is more ancient as demonstrated by the ubiquitous distribution.
The first mutation C282Y is of Celtic origin, the second H63D is even more ancient, it's distribution is ubiquitous

Anyway, the important thing is these studies don't assess over all genetic affinity or anything like that. I don't deny that there is a correlation between some of these and "northern influence", in the C282Y mutation in particular, but we would need samples from all European populations as well to get an idea how much. Most Italians don't even carry these markers, northern or otherwise.

J Richards writes :
The prevalence of right-handedness is lower in blonds:

Schachter SC, Ransil BJ, Geschwind N. Associations of handedness with hair color and learning disabilities. Neuropsychologia. 1987;25(1B):269-76.

The prevalence of right-handedness is lower in Northern Italians than in Central Italians, and the prevalence of right-handedness is lower in Central Italians than in Southern Italians:

Pia Viggiano M, Borelli P, Vannucci M, Rocchetti G. Hand preference in Italian students. Laterality. 2001 Jul;6(3):283-6.


Neither sources say anything about the differences being because of Germanic admixture in the North. I never denied that Northern Italians had higher blondism frequencies than Southern Italians, lol I'm pretty sure if you read Carleton Coon's "The Races Of Europe" he has Northern Italians around as blonde as the Spanish and less blonde than Basques overall.

On Spaniards
"Two widely observed racial characters serve to differentiate the Spaniards from most of the living inhabitants of Arabia and North Africa: hair color and nasal profile. In Spain, as a whole, some 29 per cent of the male population has black hair, some 68 per cent dark brown, while traces of blondism are visible in 17 percent."

On Basques
"Black hair is found in 7 per cent of the group, brown in 77 per cent, and light brown to blond in 16 per cent."

On Northern Italians
"Observational data on the poulation of the neighborhood of Bologna78 permits, by contrasts to the foregoing, a study in some detail of a North Italian population, one with a mean stature of about 168 cm. and a mean cephalic index of about 83 or 84. The skin color of the face is about equally divided between light brown and pinkish-white; the hair is black in 25 per cent, dark brown in 60 per cent, and light brown to blond in the rest of cases"
On Southern Italians
"About 20 per cent have black hair, and 48 per cent dark brown; reddish brown shades, or dark to medium brown with a reddish glint, account for some 16 per cent, while the remaining 6 per cent have light brown or blondish colors."

In Contrast, Northern Germans
"The hair is brown as a rule among adults; 54 per cent could be classed as dark brown (Fischer #27, 4-7); the rest are divided between golden and ashen shades of light brown and blond."
"Sixty per cent of the Vogelberg seems to possess blond or light-mixed complexion, while only 9 per cent can be called completely brunet."

Swedes and Norwegians
"According to the Anthropologia Suecica, 52 per cent of Swedes had ash-blond hair, and 23 per cent golden. Thus the proportions of these two classes of blondism are reversed in comparison to Norway. The two countries are about equal in amount of dark hair shades, but, by and large, Norway would seem to be lighter haired than Sweden"

SOURCE : Coon, C.S., 1939, The Races of Europe, New York (Macmillan)

http://www.theapricity.com/snpa/racesofeurope.htm

They seem to fall into the Southwestern European norm in blondism frequencies not much different than Basques or Spanish, doesn't sound like much of a "Northern European character" to me. Anyway the different distribution of blondism in Italy obviously pre-dates anything Germanic.


And lastly a he posts a Y chromosomal frequency study

"Take a look at the distribution of the Y haplogroup P* (xR1a) in Italy, from a study by Giacomo et al.




Italian P* (xR1a) variation

Before you think that there is anything clinal about the P* (xR1a) haplogroup in Italy, take a look at the autocorrelation index, whereby there is a sharp decrease in genetic similarity for samples separated by >800 km, i.e., Northern vs. Southern Italy.

autocorrelation index

Based on 10 Y haplogroups, look at the large genetic difference between Northern and Southern Italians (Fct = 8.15%).

molecular variance

Now, the P* (xR1a) haplogroup is the signature of the Paleolithic inhabitants of the entire European continent, and the Brace et al. paper has already shown that the vast majority of Northern and Central Europeans, and to a lesser extent Southern Europeans, are the descendents of the Paleolithic inhabitants of Europe. An STR haplotype within the P* (xR1a) haplogroup is a characteristic feature shared by Celtic-speaking populations and the Basques, and in this context, the most frequent YCAII and DYS413 STR alleles observed in Hg P* (xR1a) from the Trentino and Tuscany populations in Northern Italy were identical to the ones observed in 73% of Basques in the study by Giacomo et al.

The data in the three images above is from:

Di Giacomo F, Luca F, Anagnou N, Ciavarella G, Corbo RM, Cresta M, Cucci F, Di Stasi L, Agostiano V, Giparaki M, Loutradis A, Mammi’ C, Michalodimitrakis EN, Pßapola F, Pedicini G, Plata E, Terrenato L, Tofanelli S, Malaspina P, Novelletto A. Clinal patterns of human Y chromosomal diversity in continental Italy and Greece are dominated by drift and founder effects. Mol Phylogenet Evol. 2003 Sep;28(3):387-95."


Well he is correct in saying that Haplogroup P*(xR1a) is a paleolithic haplogroup. Which basically means it entered Europe in the Paleolithic period. If you're wondering what P*(xR1a) means, it means all downstream clades of haplogroup P excluding R1a. Haplogroup P gave rise to haplogroup R1 and Q. If you're confused look at this haplogroup tree below.


I would like to mention that R1 is not the only Paleolithic haplogroup in Europe, haplogroup I actually arose in Europe, and has also been there since the Paleolithic. However, as you can see haplogroup I is not a downstream clade of P. So this study doesn't even cover haplogroup I and thus not the over all assessment of "paleolithic lineages in Italy and Greece". Now, getting back to P, it's son haplogroup Q has like a less than 1% frequency in Italy and is very very minimal in Europe. R1 on the other hand is a major clade in Europe. So this study is little more than the frequency of R1b in Italy and Greece. He is correct in saying that P*(xR1a) [basically R1b] is very common in former Celtic lands and Basque territory. Such as France, Northern Italy, Spain, and the British Isles. But how does this have anything to do with Germanic invasions or being Northern European? Maybe he thinks because Northern Europeans are more Paleolithic and less Neolithic than Southern Euros as a whole, this would prove Northern Italians are very Northern European like. But the frequencies of R1b are as common in Spain as they are in Northern Italy. EUpedia has a good breakdown of the haplogroup frequencies in Europe, and you can see that here http://www.eupedia.com/europe/european_y-dna_haplogroups.shtml

But anyway, you can't assess over all genetic structure by haplogroups.

"Previous studies of human population structure have primarily considered different continental populations or admixed populations between two or more different continental populations. However, some of these studies have also suggested that sub-continental differences in population structure can be discerned. The examination of population differences within Europe using mitochondrial or Y chromosome haplogroups has been particularly useful in tracing part of the routes of migration and populating of Europe, but these haplogroups do not provide strong inferences on population genetic structure."
SOURCE : Seldin MF, Shigeta R, Villoslada P, Selmi C, Tuomilehto J, et al. (2006) European Population Substructure: Clustering of Northern and Southern Populations. PLoS Genet 2(9): e143. doi:10.1371/journal.pgen.0020143

http://www.plosgenetics.org/article/info%3Adoi%2F10.1371%2Fjournal.pgen.0020143

You can't assess genetic structure of a population by haplogroup frequencies in populations..... for lots of reasons; such as genetic drift/founder effects/population bottlenecks, etc. And you can't assess an individual's over all genetic affinity/structure because a haplogroup is just a single locus that functions as a "marker". As far as Paternal lineages, it tells you about your father, you father's father [that's 1/4th of your ancestry], you father's father's father [1/8th of your ancestry]. etc. Going all the way back to the paleolithic? Yeah.

Anyway, back on topic. If we were to go by Haplogroup frequencies of P*(xR1a) in Europe, then the British and Spanish would be pretty similar, but on genome wide association studies [which i will show in a minute] the British cluster way up with Northern Europe, while the Spanish who have as great amount of R1b or more than Northern Italians are very distinct from them, and cluster in Southern Europe. If we exclude the Southern French, the Spanish do seem to be the most "Northern Influenced" Southern Europeans though.

So basically the Richard's posted study cannot be used to prove the "Northern European character" of the Northern Italians since haplogroups are inefficient to make such statements on. And also, nowhere does the study say that the differences between North and South Italy in P*(xR1a) are because of Germanic incursions.



Anyway, lets get to my claims.

1. That Northern Italians are not significantly Germanic influenced
2. That Northern Italians share less over all ancestry and are less related to Northern Europeans than the Spanish are.


That's all I ever claimed. And these are facts.

I did not claim that Northern Italians are not blonder than Southern Italians. [Although I would claim that Northern Italians are in the general Southwestern European range in hair and eye color frequencies].

I did not claim that Southern Italians are as biologically close to Northern Europeans/Germanic groups as Northern Italians are.

I did not claim that there is not a pretty sizable and detectable difference between Northern-Central Italians, and Southern Italians.


Anyway, lets get to fact 1, that Italians [including Northerners] are not significantly Germanic influenced.

"Statistical techniques for displaying the geographical distribution of many genes in few synthetic images have been used to represent the various patterns of gene frequencies in Europe and in the world (Menozzi et al. 1978; Piazza et al. 1981a). It has also been shown that such synthetic displays are particularly useful in detecting clines of genetic differentiation associated with movements of populations like those accompanying the Neolithic expansion of farmers from the Near East or, in more recent times, the putative diffusion of Indo-European-speaking populations (Ammerman & Cavalli-Sforza, 1984; Gimbutas, 1973).

In this paper we use the same combination of statistical and graphical techniques to study the genetic structure of Italy, a European country whose unity of people and cultures was quite a recent event. The possibility of studying genetic differentiation in a small geographical area is tested and trends of genetic differences are tentatively interpreted in terms of historic and linguistic knowledge. The few demographic pieces of information taken from historical sources and compared with linguistic records support the hypothesis that the genetic structure of Italy still reflects the ethnic stratification of pre-Roman times."
SOURCE : Piazza, A., N. Cappello, E. Olivetti, and S. Rendine. 1988. A genetic history of Italy. Ann. Hum. Genet. 52:203-213.

http://onlinelibrary.wiley.com/doi/10.1111/j.1469-1809.1988.tb01098.x/abstract

If geneticists are in agreement that biological stratification of Italy is still reflective of the times before Rome dominated the peninsula [so that would be what? before the 2nd Punic War?], then there's no way any Italians are largely Germanic influenced. Since Germanic tribes didn't invade until way later. The Lombards not till after the fall of Rome in 500+ AD.

A recent genome wide IBD (Identity-By-Descent) study has corroborated with this fact, and shows that Italians [which includes Northern, Central, and Southern Italians] and Iberians have very minimal IBD sharing with Northern Europeans over the last 1,500 years. And quite plainly states Germanic tribes have had a weak genetic impact on both Italy and Spain.

The geography of recent genetic ancestry across Europe

Peter Ralph, Graham Coop
(Submitted on 16 Jul 2012)

"The recent genealogical history of human populations is a complex mosaic formed by individual migration, large-scale population movements, and other demographic events. Population genomics datasets can provide a window into this recent history, as rare traces of recent shared genetic ancestry are detectable due to long segments of shared genomic material. We make use of genomic data for 2,257 Europeans (the POPRES dataset) to conduct one of the first surveys of recent genealogical ancestry over the past three thousand years at a continental scale. We detected 1.9 million shared genomic segments, and used the lengths of these to infer the distribution of shared ancestors across time and geography. We find that a pair of modern Europeans living in neighboring populations share around 10-50 genetic common ancestors from the last 1500 years, and upwards of 500 genetic ancestors from the previous 1000 years. These numbers drop off exponentially with geographic distance, but since genetic ancestry is rare, individuals from opposite ends of Europe are still expected to share millions of common genealogical ancestors over the last 1000 years. There is substantial regional variation in the number of shared genetic ancestors: especially high numbers of common ancestors between many eastern populations likely date to the Slavic and/or Hunnic expansions, while much lower levels of common ancestry in the Italian and Iberian peninsulas may indicate weaker demographic effects of Germanic expansions into these areas and/or more stably structured populations. Recent shared ancestry in modern Europeans is ubiquitous, and clearly shows the impact of both small-scale migration and large historical events. Population genomic datasets have considerable power to uncover recent demographic history, and will allow a much fuller picture of the close genealogical kinship of individuals across the world."
Notice in the figure below, appreciable IBD sharing between Italy and Iberia with Northern Europe is only from the 1515-2535 years ago period. The past 1,500 years for both groups with Northern Europe has been minimal.

SOURCE : Peter Ralph, Graham Coop, The geography of recent genetic ancestry across Europe Populations and Evolution, arXiv:1207.3815v2 [q-bio.PE]

http://arxiv.org/abs/1207.3815


Anyway, lets get to fact 2, that Northern Italians are [very slightly] less related to Northern Europeans than the Spanish are.

Well i'm sure you've read this blogpost of mine and the genome wide studies i post.

European Population Substructure: Clustering of Northern and Southern Populations
Seldin et al (2006).

"Using a genome-wide single nucleotide polymorphism (SNP) panel, we observed population structure in a diverse group of Europeans and European Americans. Under a variety of conditions and tests, there is a consistent and reproducible distinction between “northern” and “southern” European population groups: most individual participants with southern European ancestry (Italian, Spanish, Portuguese, and Greek) have >85% membership in the “southern” population; and most northern, western, eastern, and central Europeans have >90% in the “northern” population group. Ashkenazi Jewish as well as Sephardic Jewish origin also showed >85% membership in the “southern” population, consistent with a later Mediterranean origin of these ethnic groups. Based on this work, we have developed a core set of informative SNP markers that can control for this partition in European population structure in a variety of clinical and genetic studies."

Northern Italians are sampled in the group

"The Italian participants were normal healthy volunteers recruited from throughout Italy: 38 from northern Italy, 23 from central Italy, and 30 from southern Italy"
"Grouping of individuals with different north–south contributions from the k = 2 analysis further illustrates this division of individual participants from different European population sets and some of the variability observed (Figure 2). Italy (84 of 86 individuals), Spain (66 of 74), Portugal (3 of 3), and Sephardic Jewish Americans (3 of 3) had majority contributions from the “southern” population group as defined by this population structure analysis. In addition, a large fraction of southern European Americans (7 of 11) without other reported European heritage had majority “southern” contribution. Those Americans with self-identified mixed “southern” and “northern” heritage showed a substantial but less impressive “southern” population component (8 of 23 with majority “southern”). Those American participants with mixed eastern Mediterranean–reported heritage also had two of ten individuals with a majority “southern” population component. All other groups showed only a few isolated participants with more than a limited “southern” population component. Trends in both the Italian and Spanish participants were also consistent with this north–south pattern: ten of 32 participants from northern Italy had greater than a 10% “northern” component compared with two of 28 from southern Italy; and 23 of 43 from northern Spain had greater than a 10% “northern” contribution compared to five of 19 from southern Spain."Analyses were performed with 2,657 SNPs under the condition of two population (Pop) groups (k = 2)."

SOURCE : Seldin MF, Shigeta R, Villoslada P, Selmi C, Tuomilehto J, et al. (2006) European Population Substructure: Clustering of Northern and Southern Populations. PLoS Genet 2(9): e143. doi:10.1371/journal.pgen.0020143

http://www.plosgenetics.org/article/info%3Adoi%2F10.1371%2Fjournal.pgen.0020143


Another couple of genome wide studies, but instead of using the STRUCTURE program [structuring the populations into a certain number of groups based on a genetic clustering algorithm (i don't know how they do it, it's really complicated math/science), which in the above was only 2], these studies just map the genetic affinities of each population out. You can follow the keys, and you'll see The Spanish are slightly closer to Northern Europeans than Northern Italians are. Although Northern Italians are definitely more Northern Influenced and share more ancestry with Northern Europeans than Southern Italians or Greeks. Anyway

Refinement of ancestry informative markers in Europeans
Tian et al (2009).

"The definition of European population genetic substructure and its application to understanding complex phenotypes is becoming increasingly important. In the current study using over 4,000 subjects genotyped for 300,000 single-nucleotide polymorphisms (SNPs), we provide further insight into relationships among European population groups and identify sets of SNP ancestry informative markers (AIMs) for application in genetic studies. In general, the graphical description of these principal components analyses (PCA) of diverse European subjects showed a strong correspondence to the geographical relationships of specific countries or regions of origin. Clearer separation of different ethnic and regional populations was observed when northern and southern European groups were considered separately and the PCA results were influenced by the inclusion or exclusion of different self-identified population groups including Ashkenazi Jewish, Sardinian, and Orcadian ethnic groups. SNP AIM sets were identified that could distinguish the regional and ethnic population groups. Moreover, the studies demonstrated that most allele frequency differences between different European groups could be controlled effectively in analyses using these AIM sets. The European substructure AIMs should be widely applicable to ongoing studies to confirm and delineate specific disease susceptibility candidate regions without the necessity of performing additional genome-wide SNP studies in additional subject sets."

"Figure 1. Principal component analyses of substructure in a diverse set of subjects of European descent. Graphic representation of the first two PCs based on analysis with >250K SNPs are shown. Color code shows subgroup of subjects for each population group.
The subjects included Adygei (ADY, 12 subjects), Ashkenazi Jewish American (AJA, 40 subjects), Basque (BAS, 12 subjects), Bedouin (BDN, 23 subjects), CEPH European American (CEU, 48), Druze (20 subjects), Eastern European American (EEUR, 11 subjects), German American (GERM, 17 subjects), Greek American (GRK, 7), Hungarian American (HUN, 4 ), IRISH (84 subjects), Italian American (ITN, 20 subjects), northern Italian (ITN_N, 13 subjects), Dutch American (NETH, 3 subjects), Orcadian (ORC, 14 subjects), Palestinian (PAL, 22 subjects), Russian (RUS, 13 subjects), Sardinian (SARD, 28 subjects), Scandinavian American (SCAN, 6 subjects ), Spanish (SPAIN, 12 subjects), Swedish (SWED, 591 subjects), Tuscany (TUSC, 8 subjects), and United Kingdom American (UK, 5 subjects). Each of the specific country or ethnic color coded origins had consistent 4 grandparent origin information. The total number of individuals in this analysis was 4446. In panel A European Americans (EURA) without 4 grandparental information are shown (contains both NYCP and CHOP). Panels B and C illustrate the distribution of the EURA from NYCP (1873 subjects) and CHOP (1488 subjects), respectively."


SOURCE : Tian et al. (2009). European Population Genetic Substructure: Further Definition of Ancestry Informative Markers for Distinguishing Among Diverse European Ethnic Groups. Mol Med; doi: 10.2119

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2730349/


Genetic Structure of Europeans: A View from the North–East.
Nelis et al. (2009).

"Using principal component (PC) analysis, we studied the genetic constitution of 3,112 individuals from Europe as portrayed by more than 270,000 single nucleotide polymorphisms (SNPs) genotyped with the Illumina Infinium platform. In cohorts where the sample size was >100, one hundred randomly chosen samples were used for analysis to minimize the sample size effect, resulting in a total of 1,564 samples. This analysis revealed that the genetic structure of the European population correlates closely with geography. The first two PCs highlight the genetic diversity corresponding to the northwest to southeast gradient and position the populations according to their approximate geographic origin. The resulting genetic map forms a triangular structure with a) Finland, b) the Baltic region, Poland and Western Russia, and c) Italy as its vertexes, and with d) Central- and Western Europe in its centre. Inter- and intra- population genetic differences were quantified by the inflation factor lambda (λ) (ranging from 1.00 to 4.21), fixation index (Fst) (ranging from 0.000 to 0.023), and by the number of markers exhibiting significant allele frequency differences in pair-wise population comparisons. The estimated lambda was used to assess the real diminishing impact to association statistics when two distinct populations are merged directly in an analysis. When the PC analysis was confined to the 1,019 Estonian individuals (0.1% of the Estonian population), a fine structure emerged that correlated with the geography of individual counties. With at least two cohorts available from several countries, genetic substructures were investigated in Czech, Finnish, German, Estonian and Italian populations. Together with previously published data, our results allow the creation of a comprehensive European genetic map that will greatly facilitate inter-population genetic studies including genome wide association studies (GWAS)."


Italian samples were from
Northern Italy:
"The Northern Italian samples have been randomly collected from the Borbera Valley. The Borbera Valley is located in Northern Italy, namely the northern part of the Apennines mountains, between Liguria and Piedmont, about 80 km south of Milan. For the current analysis, 96 individuals were selected from the database where all the samples have complete phenotypic data."

Southern Italy:
"The Italian samples were randomly chosen from those enrolled in a population study named Carlantino Project, which is focused on inhabitants arising from an isolated village at the border between Central and Southern Italy (Province of Foggia, Region of Apulia with 1200 inhabitants)."
SOURCE : Nelis M, Esko T, Mägi R, Zimprich F, Zimprich A, et al. (2009) Genetic Structure of Europeans: A View from the North–East. PLoS ONE 4(5): e5472. doi:10.1371/journal.pone.0005472

http://www.plosone.org/article/info:doi%2F10.1371%2Fjournal.pone.0005472


Jarus writes
"I concede the point about there being Germanic admixture in Northern Italy, you have me there. However, there were many important Renaissance figures (other than rulers) who displayed Mediterranean features, such as Michelangelo."

So there you go, you were duped way too easily. Notice the studies he posted, the authors never insinuated what he was saying they meant? (Particularly the data in his studies proving large Germanic admixture). That alone is always an eyebrow raiser. Anyway, you are somewhat correct that there is Germanic admixture in North Italy, but it's obviously minimal. There's probably some minimal Germanic ancestry in South Italy as well because of the Normans and wandering Visgoths, etc.
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