The Yamnaya were nomadic herders from the steppe in what is now Ukraine and Russia. Archaeological evidence shows that they…

“The Yamnaya were nomadic herders from the steppe in what is now Ukraine and Russia. Archaeological evidence shows that they swept into Europe around 4,500 years ago, bringing with them horses, wheels, their famous “kurgan” burial mounds and quite possibly Proto-Indo-European, the ancestral tongue of most European, as well as many South Asian languages. Just like farming before it, their package of resources, technologies and behaviours gave them an advantage over the pre-existing Europeans and they seem to have left a substantial genetic legacy across Europe.”

–Daniel Zadik in War in Context ( The Conversation).A handful of Bronze-Age men could have fathered two thirds of Europeans (viaprotoslacker)