We realize, therefore, that even in these faraway places, whose study requires a certain level of archaeological knowledge, issues that appear to be … - Jean-Paul Demoule

Which components of the reconstructed Indo-European proto-culture can be used as evidence of a steppic location?... two arguments are generally singled out by the proponents of the steppic theory: the case of the horse and that of the chariot. The domesticated horse, on the one hand, and the chariot on the other, are supposedly well-attested in the shared vocabulary and are particularly valorized in the earliest Indo-European mythologies, where the sacrifice of a horse is the ultimate royal sacrifice... The most common root for the horse is certainly found in a significant number of Indo-European languages... Its absence in Slavic is all the more surprising since the historical “cradle” of the Slavs is often said to be located in the North Pontic Steppes, or close by, precisely where the earliest domestication of the horse is reputed to have occurred.

...there is only one solution left to save the invasionist model, or at least the concept of an “arrival of the Indo-Iranians”: invisible migrations. To this end, James Mallory, for example, came up with the military-inspired notion of Kulturkugel (“culture bullets”)—as if, perhaps, a Germanic term might excuse, almost in a humorous manner, the use of a diffusionist model by an English-speaking author. Mallory’s explanatory drawing shows a rifle cartridge (or a shell, depending) in which the bullet itself is the material culture and the charge is the language. Thus, the Indo-Aryan nomads of the steppes would have traveled across the BMAC, shedding their entire material culture on the way but not their language. Having thus become archaeologically undetectable, they would then have descended toward the Indus Plains to impose their new culture and their preserved language; this new culture would have had no known archaeological equivalent at the time.

It is presumptuous to say the least to claim that the migratory routes traveled by the Indo-Europeans from their original Homeland have now been clearly traced.