First my thoughts and personal opinion on our genetic:
Italy is a southern european country; therefore as one of those it belongs greatly to the mediterranean world; it's like the opposite of sweden but in the same way it's a refuge for mediterranean phenotypes, and many mediterranean types are found.
gracile med mostly, some tall ones, and many with a south eastern vibe.
italy is in the centre of mediterranean europe, therefore it received inputs from many part of southern europe, a great part of it belongs to the east med basin type, expecially in southern italy where in the past were greek colonies, the etruscans in tuscany that came from anatolia and arrived there from the crescent valley (tigri/eufate) i think.
the arab influence is scarce and restricted to some place of sicily.
Recent genetic studies confirm all that i've said: Italy is collocated in southern europe and clusters between the iberians (spain/portugal) , and in some studies also with southern France and greece; northern italy is towards the iberian cluster and southern italy towards the greek one.
people near italy: Spain/Portugal, France, Switzerland, Greece, Bulgaria, Romania, Macedonia
taken from Wikipedia:
During prehistory, Italy was populated by different but very similar Indo-European groups, later collectively listed amongst the Ancient peoples of Italy, of whom the Italic one was predominant.
Not all of these various peoples were linguistically or ethnically closely related. Some of them spoke Italic languages, others spoke Greek because of the arrival of Hellenic colonists, while others belonged to another Indo-European branch (Ligurian, Venetic, Lepontic, Messapian) or were non-Indo-European (Etruscan, Raetic).
The identity of a people, as well as being characterized by notions of culture is also characterized by processes of genetic evolution. Following scientific research carried out by dutch genetists, Italy has proven to be one of the last two remaining genetic islands across Europe (along with Finland), this due to the presence of the chain Alpine mountain that, over the centuries, has prevented large migration flows aimed at colonizing the Italian lands.
• The modern man appeared during the Upper Palaeolithic. Specimens of Aurignacian age were discovered in the cave of Fumane and dated back about 34,000 years ago. During the Magdalenian period the first men from the Pyrenees populated Sardinia .
• During the Neolithic farming stable is introduced by people from the east and the first villages are built, the weapons become more sophisticated and the first objects in clay produced.
• In the late Neolithic era the use of copper spreads and villages are built over piles near the lakes. In Sardinia, Sicily and part of “Continental Italy” the Beaker culture, which probably represents the western branch of the Corded Ware culture, also spreads from North-West Europe,.
• During the Late Bronze Age in Italy appears the Urnfield or Villanovan culture characterized by the typical rite of incineration of the bodies originating from Central Europe, the use of iron spreads . In Sardinia the Nuragic civilization flourishes.
• From the 8th century BC Greek colonists settle on the southern coast and in Sicily and found cities, initiating what was later called Magna Graecia. In the 5th century Celtic tribes from continental Europe settled in Northern Italy. The Etruscan civilization developed on the coast of Tuscany and Latium.
• With the Fall of the Roman Empire different populations of German origin intruded into Italy, the most significant was that of the Lombards, who will try to unify politically the “Boot of Italy”.
During the Late Republic and throughout the Imperial period in Italy there was a process of genetic homogenization among the Italian peoples (those other peoples whom inhabited the Italian Peninsula) and the Romans. With the founding of new towns and the colonization of lands in Cisalpine Gaul and southern Italy, there was a significant migration on both the two poles of the Peninsula. The Romans encouraged the migration, as sought to destabilize local governments through forced migration. The Romans, realizing that Rome, meaning the city, could never alone monitor dozens of different peoples, with some initial resistance (which then caused the Social War), decided to extend Roman citizenship to all Italian peoples (with some exceptions) was the first step towards Rome understood not as only a city that dominated the world, but as Italy, which extends its domains throughout Europe. Following the Social War the remaining native population (Celts, Venetics, Oscans, Umbrians, Sicilians, the Greeks, Etruscans, etc. ..), obtained citizenship and mingled with the Roman settlers. Romanization in central Italy had been successful, so much so that many politicians and Roman writers came from that moment from Marche, Abruzzo and Umbria. Greek colonists in southern Italy, which coexisted with Italic peoples, were also immediately Romanized and colonized. In addition Northern Italy was Romanized.. The phenomenon of Roman colonization in Italy was held for nearly six centuries and blocks of 6,000 households (30,0000 individuals on assumes) were moved from South to North and vice versa, descendants of Roman settlers living in the north (some times with good amount of gallic genes and Etruscan) were moved to South so flows from North to South lasted for centuries.
Although Sardinians also do not constitute a homogeneous population, Sardinia has unique genetic composition, when compared to other Italian, European and Mediterranean populations. Migration from the Iberian peninsula, rather than southern France or Liguria, may have resulted in a common Y-chromosome haplogroup I being present.