Imo, it’s just as likely that the genetic material was brought in to the Italian AO with the Goths or Vandals, rather than the current gene mix indicating something unique about the peninsula back in the time of the actual mixing.
Since the Brits were also mentioned in the article...
Imo, any sampling of Brit DNA is only going to provide info on the DNA carried into the island starting with the Roman conquest and forward. I doubt there’s a whole lot of DNA remaining in Britain that wasn’t transported to that AO from elsewhere within recorded history.
The Etruscans, for whom Tuscany is named, were probably not native to Italy. They are thought to have arrived from an as yet unknown place, probably somewhere in Anatolia, prior to the rise of Rome. They were amazing civil engineers, metalworkers and artisans and the Romans built their cities and culture largely upon the Etruscan model. Any genetic mixing with Neanderthals occurred long before their arrival in Tuscany.
From Wiki: "A DNA study performed in Italy ... partly gave credence to the theory of Herodotus, as the results showed that 11 minor mitochondrial DNA lineages extracted from different Etruscan remains occur nowhere else in Europe and are shared only with Near Eastern Anatolian people."
Not so says Stephen Oppenheimer in his book: Origins Of The British
"The genetic evidence shows that three quarters of our ancestors came to this corner of Europe as hunter-gatherers, between 15,000 and 7,500 years ago, after the melting of the ice caps but before the land broke away from the mainland and divided into islands. Our subsequent separation from Europe has preserved a genetic time capsule of southwestern Europe during the ice age, which we share most closely with the former ice-age refuge in the Basque country. The first settlers were unlikely to have spoken a Celtic language but possibly a tongue related to the unique Basque language."
"Another wave of immigration arrived during the Neolithic period, when farming developed about 6,500 years ago. But the English still derive most of their current gene pool from the same early Basque source as the Irish, Welsh and Scots. These figures are at odds with the modern perceptions of Celtic and Anglo-Saxon ethnicity based on more recent invasions. There were many later invasions, as well as less violent immigrations, and each left a genetic signal, but no individual event contributed much more than 5 per cent to our modern genetic mix."