subcultures, Indo-European languages spread west, south and east starting around 4,000 BCE. These languages may have been carried by small groups of males, with patron-client systems which allowed for the inclusion of other groups into their cultural system. Eastward emerged the Sintashta culture (2050–1900 BCE), where common Indo-Iranian was spoken. Out of the Sintashta culture developed the Andronovo culture (2000–1450 BCE), which interacted with the Bactria-Margiana culture (2250–1700 BCE). This interaction further shaped the Indo-Iranians, which split at sometime between 2000 and 1600 BCE into the Indo-Aryans and the Iranians. The Indo-Aryans migrated to the Levant and South Asia. The migration into northern India was not a large-scale immigration, but may have consisted of small groups which were genetically diverse. Their culture and language spread by the same mechanisms of acculturalisation, and the absorption of other groups into their patron-client system. Anthropology: elite recruitment and language shift Indo-European languages probably spread through language shifts. Small groups can change a larger cultural area, and elite male dominance by small groups may have led to a language shift in northern India. David Anthony, in his "revised Steppe hypothesis" notes that the spread of the Indo-European languages probably did not happen through "chain-type folk migrations", but by the introduction of these languages by ritual and political elites, which were emulated by large groups of people, a process which he calls "elite recruitment". According to Parpola, local elites joined "small but powerful groups" of Indo-European speaking migrants. These migrants had an attractive social system and good weapons, and luxury goods which marked their status and power. Joining these groups was attractive for local leaders, since it strengthened their position, and gave them additional advantages. These new members were further incorporated by matrimonial alliances. According to Joseph Salmons, language shift is facilitated by "dislocation" of language communities, in which the elite is taken over. According to Salmons, this change is facilitated by "systematic changes in community structure", in which a local community becomes incorporated in a larger social structure. Genetics: ancient ancestry and multiple gene flows The Indo-Aryan migrations form part of a complex genetic puzzle on the origin and spread of the various components of the Indian population, including various waves of admixture and language shift. Studies indicate north and south Indians share a common maternal ancestry. A series of studies show that the Indian subcontinent harbours two major ancestral components, namely the Ancestral