A Harvard study indicates that the invading people was responsible for almost all the offspring from that time onward. Genetic traits indicate the same, including a "complete replacement of the Y chromosome"
Nearly 4,500 years ago, an invasion practically exterminated all the men of the Iberian Peninsula, so the modern inhabitants of Portugal and Spain descend almost exclusively from the invaders. The study comes from Harvard and is directed by David Reich, who explained the findings at a New Scientist event.
Reich explained that the invading culture came from the Caucasus and the northern Black Sea coast, around the end of the Copper Age and early BronzeAge."These people spread over a vast territory from Mongolia to Europe, and are the single primary most important contributors to Europeans today", said David Reich quoted by Europa Press.