 Some subclades of C and D closer to the Native American subclades occur among Mongolian, Amur, Japanese, Korean, and Ainu populations.A 2019 study suggested that Native Americans are the closest living relatives to 10,000-year-old fossils found near the Kolyma River in northeastern Siberia.The development of high-resolution genomic analysis has provided opportunities to further define Native American subclades and narrow the range of Asian subclades that may be parent or sister subclades.