Our results also show that local regions in Honshu Island the largest island of Japan are still genetically differentiated, even though human migration within Japan has become rather frequent in the past years or so. Our finding that the individuals from Tohoku were less related to Han-Chinese individuals than were the individuals from Kinki and Kyushu suggests that the individuals in Tohoku were less affected by immigrants from the Asian continent than were the individuals in Kinki.
Our finding that the individuals from the western areas in the Hondo cluster had smaller values of Eigenvector 2 than did those in the eastern areas may be because the northeast areas of Japan, such as Tohoku, are distant from the main contact point to the Asian continent.
On the other hand, the individuals from Kanto-Koshinetsu and Hokkaido were broadly distributed in the PCA plots, which is not consistent with the east-west trend of genetic differentiation. The broad distribution of the individuals from Kanto-Koshinetsu may be due to recent migrations from various areas of Japan into the Kanto area. The Kanto area includes large cities, such as Tokyo and Yokohama, and recent migrations from various areas of Japan into the Kanto area may have obscured ancient genetic differentiation in the Kanto area.
The individuals in Hokkaido are similar to those in the Kanto-Koshinetsu area, even though Hokkaido is located at the north end of Japan. This is probably because most of the people living in Hokkaido are descendents of people who moved from Honshu.
Previous studies showed genetic affinities between the Ainu and Ryukyu peoples, 21 and 33 who live in the north and south ends of Japan, respectively, and who are thought to be descendents of the Jomon people. In the Yayoi period, immigrants from the Asian continent had moved to western Japan via Korea or China and expelled or mixed with the Jomon people. Our observations of the two main clusters and genetic differentiation among geographic regions are not discordant with the dual-origin hypothesis, although most of the Hokkaido individuals in this study are probably different from the indigenous Ainu people.
Most of the people living in Okinawa Island are probably derived from the Jomon people, whereas most of the people living in Hondo are probably derived from the Yayoi people or are a mixture of the Yayoi and Jomon peoples. Individuals in Tohoku showed two interesting features that are difficult to attribute to only local genetic differentiation.
First, within the Hondo cluster, the individuals from Tohoku were closest to the individuals from Okinawa with respect to Eigenvector 1 Supplemental Data.
These observations might reflect ancient population affinities between Tohoku and Okinawa, which have been obscured by the gene flow between their geographic neighbors in Honshu Island.
The presence of two main clusters may also be explained by the long-term isolation of populations in the Ryukyu Islands. The distinct difference between the Hondo and the Ryukyu clusters is probably due to two factors: there were two major migrations to Japan, and populations in the Ryukyu Islands became genetically differentiated by isolation.
Some of those individuals might be genetically non-Japanese East Asians, and others may have mixed Japanese and non-Japanese East-Asian ancestries. Further analyses including individuals from other areas of Asia would be desirable for understanding the Japanese population structure in detail, considering recent migrations from neighboring countries.
This is because these SNPs were associated with phenotypic variations, 30 and 31 and it was suggested that the increase in the frequencies of the specific alleles were driven by positive selection. These observations suggest that a search for differentiated nonsynonymous SNPs between closely related subpopulations, like the Hondo and the Ryukyu clusters, would be an efficient approach to finding SNPs that are involved in phenotypic variations and have been under natural selection.
We should be careful when inferring from allele—trait associations that are detected in the genomic regions where relatively higher differentiations were observed e. Because of the genetic differentiation among geographical regions in Japan, the design of a GWAS needs to take into account the structure of the Japanese population, especially if there are differences in disease prevalence among geographical regions of Japan.
In the present study, we used individual genotype data to conduct simulations in order to examine to what extent the population stratification causes an increase of false-positive rates in association studies. More generally, we propose the following approaches to avoidance of an inflation of false positive rates in a GWAS for the Japanese population: 1 If either cases or controls include individuals from the Ryukyu cluster in different but small proportions, simply exclude them in the studies.
The Greeks and the Etruscans were primarily responsible for the spread of J2 in the southern and western Mediterranean regions, which included Assyria, Babylonia, and Phoenicia. Is there a deep history Sumerian connection or Near Eastern layer to Japanese prehistory? Thank you for posting a link to my article.
This is to inform you that the article has been moved. Very interesting and informative article. I was wondering if you are doing any DNA testing on indigenous people of 0kinawan descent. My parents who are in their mid eighties just had their DNA done by family ancestry and I was a bit disappointed to find they just listed them in the general area of Asian east and it was from Russia to the Phillipines.
It also mentioned Pacific Islander under Melanesia. My fathers mother had wavy hair and my dad had lots of curls as did his siblings and some of my cousins. My cousins are also of Okinawan ethnicity but have very Polynesian type hair. My one male cousin looks Samoan with an Afro. I tend to believe they missed something on my dads markers. These cultural differences are a great reason for anyone in Japan to visit Okinawa, to see something different. It is also why it is such a popular travelling location for many Japanese people, because they can experience a different culture without leaving their country or facing a different language.
Therefore, if you have been in Japan for quite some time and you want to experience somewhere different without going far, consider Okinawa to be your next destination. By logging in you agree to the our privacy policy and terms of use. Jan 2, Understanding differences between Okinawa and Japan If you know some things about the history of Okinawa, you might have heard about how this southern part of Japan used to be its own kingdom called Ryukyu Kingdom.
Living Food. A nice surprise! Oigawa Shizuoka tea bags! Sanrio on May 7. What drinking Shizuoka green tea everyday felt like. Sanrio on Apr In the 19th century, Ryukyu followed Japan on the path to becoming a modern country and became part of the nation building of Japan as Okinawa Prefecture. Okinawan food One of the most popular ingredients in Okinawan food is pork.
For the pig, which is said to have been introduced from China to Okinawa, all parts are consumed from the head and tail to the organs. Moreover, many vegetables including Goya bitter melon and Beni-imo sweet potato , seaweeds such as Mozuku seaweed , Umi-budo sea grapes , and fish including Gurukun Banana Fish are also eaten. Since rice is the main raw material of awamori, it is categorized as rice shochu.
However, there is a manufacturing difference between awamori and other rice shochu. While white koji mold is used for rice shochu in the second fermentation, black koji mold is used for the entire fermentation stage for awamori making.
Another primary difference is that Thai rice Indica type is usually used as raw material for awamori. Haarii Haarii is traditional dragon boat race in Okinawa.
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