on the dates for Mehrgarh) and may have continued into the period of the Indus civilization that began around 4,600 years BP and depended upon West Asian crops." "migrations from Western or Central Asia from 3,000 to 4,000 years BP, a time during which it is likely that Indo-European languages began to be spoken in the subcontinent. A difficulty with this theory, however, is that by this time India was a densely populated region with widespread agriculture, so the number of migrants of West Eurasian ancestry must have been extraordinarily large to explain the fact that today about half the ancestry in India derives from the ANI." Pre-agricultural migrations Metspalu et al. (2011) detected a genetic component in India, k5, which "distributed across the Indus Valley, Central Asia, and the Caucasus". According to Metspalu et al. (2011), k5 "might represent the genetic vestige of the ANI", though they also note that the geographic cline of this component within India "is very weak, which is unexpected under the ASI-ANI model", explaining that the ASI-ANI model implies an ANI contribution which decreases toward southern India. According to Metspalu et al. (2011), "regardless of where this component was from (the Caucasus, Near East, Indus Valley, or Central Asia), its spread to other regions must have occurred well before our detection limits at 12,500 years." Speaking to Fountain Ink, Metspalu said, "the West Eurasian component in Indians appears to come from a population that diverged genetically from people actually living in Eurasia, and this separation happened at least 12,500 years ago." Moorjani et al. (2013) refer to Metspalu (2011) as "fail[ing] to find any evidence for shared ancestry between the ANI and groups in West Eurasia within the past 12,500 years". CCMB researcher Thangaraj believes that "it was much longer ago", and that "the ANI came to India in a second wave of migration that happened perhaps 40,000 years ago." conclude that ANI and ASI were formed in the 2nd millennium BCE. They were preceded by IVC-people, a mixture of AASI (ancient ancestral south Indians, that is, hunter-gatherers related), and people related to but distinct from Iranian agri-culturalists, lacking the Anatolian farmer-related ancestry which was common in Iranian farmers after 6000 BCE. Those Iranian farmers-related people may have arrived in India before the advent of farming in northern India, and mixed with people related to Indian hunter-gatherers ca. 5400 to 3700 BCE, before the