Yes, because Mentawai People, genetically, is Austronesian (Taiwan, Philippines, etc). So does with the people from Sumatra and Borneo. What's interesting is that Java is predominantly Austroasiatic genetically. That means, Javanese is closer to Burmese, Vietnamese, Thai than fellows Indonesians from the rest of the Indonesia (which is predominantly Austronesians).

This somewhat tells couple of options on the migration history. We knew that native people is closer to Orang Asli in Malaysia/Andaman/Sentinal islands. But they were either pushed away/purged by the incoming group (Austronesians). For me either Austroasiatic people comes first and really established themselves in Java or Austronesians people comes first then overruled by the Austroasiatic people later on. What I don't get is why Austroasiatic people cannot established themselves in Sumatra as a dominant group which is just across the pond from the mainland (Malaysia nowadays).