I don't use the Pan-Asian SNP Consortium data much, but the upcoming paper on the Ainu spurred me to give it a look, because it contains an Okinawan sample (JP-RK). I calculated all f3-statistics that involved this sample, and report the lowest f3-statistic for all populations in this set that appear to be admixed:
Several of these are interesting:
- A set of Indonesian populations (ID prefix; Lamaholot, Lembata, Kambera, Manggarai) are mixed with Melanesians (AX-ME)
- A set of Indian populations appear admixed (IN prefix). It seems that the Okinawan sample acts as a surrogate for "Asian" ancestry
- Filipino populations PI-UI and PI-UN (listed as Visaya, Chabakano and Tagalog) are seen as mixtures of Okinawans and PI-UB (Ilocano)
- The three Singaporean populations (SG prefix) are seen as mixtures with Caucasoids (the SG-ID Tamil Indians with CEU), with Sunda Indonesians (SG-ML Malay with ID-SU), with Zhuang Chinese (SG-CH Singaporean Chinese with CN-CC Zhuang, northern)
- Tai Yuan from Thailand with Mlabri (TH-TU with TH-MA)
- Taiwanese (Hakka TW-HA and Minnan TW-HB) with CN-CC (Zhuang) and Jiamao (CN-JI)
- Cantonese CN-GA with Jiamao (CN-JI)
- Uygur CN-UG with West Eurasians (CEU)
An interesting question is whether the mainland East Asian Yayoi element in Japanese is more similar to Han (as the f3 statistic suggests) or to Koreans. Interestingly, Koreans themselves (KR-KR) appear admixed between Han (CN-SH) and Okinawans. So, it seems that whatever this Okinawan element represents was not limited to the isles of Japan.
I also calculated the D-statistic:
D(CN-SH KR-KR : JP-RK YRI) = -0.0154 (Z = -14.779)
which suggests indeed, that there is an excess of "Okinawan"-like ancestry in Koreans compared to the Chinese. This is very interesting, because it suggests that similarity between Koreans and Japanese is due to a common substratum in the two populations.