A 2007 analysis of the DNA recovered from human remains in archaeological sites of prehistoric peoples along the Yangtze River in China also shows high frequencies of Haplogroup O1 in the Neolithic Liangzhu culture, linking them to Austronesian and Tai-Kadai peoples. The Liangzhu culture existed in coastal areas around the mouth of the Yangtze. Haplogroup O1 was absent in other archaeological sites inland. The authors of the study suggest that this may be evidence of two different human migration routes during the peopling of Eastern Asia; one coastal and the other inland, with little gene flow between them.