I'm sure that people from Shandong contributed to the overall genetic structure of modern Koreans, but no reputable scholar will say that the primary genetic inflow came from Shandong. It is true that some Korean males have the typical Han Chinese O3 marker. However, the O2b marker is the main contributer (coming from modern-day Manchuria). Koreans also have a significant percentage of C3 (around 15%) which also came from the northern Altaic steppes (through the Koguryo-Balhae-Puyo tribes).
I know some scholars like Hyung Il Pai are sympathetic to the Shandong thesis (for her, it is more the Liaodong as the concentration point), but I don't find either one of these theses to be correct. I believe that the original invaders (I did not say inhabitants) of the Korean peninsula were Altaic-Tungus nomads who overran and assimilated the Paleo-Asiatics living in the southern parts of the peninsula. After the Altaic-Tungusics settled in their new homes, subsequent migrations entered the Korean peninsula from China, south-east Asia, and Central Asia. Though these people did contribute to the modern Korean genetic structure they did not overwhelm the original Altaic-Tungus stock.
If you look at the average modern Korean face today, you can easily detect a northern Asiatic component. However, because of the Han Chinese and south-east element, you can also easily distinguish them from a typical Mongol, Tungus, Yakut, Evenk, or Buryat living today.
A slim linguistic argument is that modern Japanese speakers are mainly Yayoi and they came from modern Manchuria (which was not part of China at the time)http://www.pliink.co...o-japanese.html
Over the last century, linguists have set out expeditions in many areas of our rich global linguistic diversity to find Japan a a proper brother or cousin. The most accepted theory of recent years points towards a connection to Korean and the inclusion of both languages in the Altaic family of languages: Turkic, Mongolian, and Tungusic (Manchu). For a while, Japanese theoreticians preferred the "Southern Theory" which posits Japan as a Malayo-Polynesian (Austronesian) language (due to some simple sound similarity and a love of word-duplication), but this has fallen out of favor due to an almost complete lack of hard evidence. Some believe in a "mixed language" between the Altaic and Austronesian strains, but very few types of these languages are accounted for on the globe. And out on the extremes of possibility, the venerable Ono Susumu of Tokyo University started seriously pursuing a connection between Japanese and the Dravidian languages in India. Right.
Although a general lack of hard evidence makes all speculation equally suspect, the current theories have enormous problems or place the genetic relationship between the two languages so far back as not to really matter much. For example, scholar Hattori Shiro puts the Japanese-Korean split back at least 4,700 years. The Altaic theory sounds plausible in principle, but there is very little connecting Japanese to Korean, let alone Korean to Tungusic or Turkish to Mongolian. Besides the much-vaunted "vowel harmony" and "agglutinative grammar," there are only a few known lexical similarities, and these may be from borrowing rather than genetic divergence.
Indiana University-Bloomington linguistics professor Christopher Beckwith's relatively new tome Koguryo: The Language of Japan's Continental Relatives offers a fascinating and plausible solution to the enduring origin puzzle. From around 100 B.C. to the 7th century A.D., modern day Korea was divided into three kingdoms: Koguryo, Shilla, and Paekche. The three states were eventually unified under Shilla in 668, and the modern Korean language originates from the language spoken in Shilla. Koguryo and Paekche, however, had different languages which are posited to be related to each other. Scholars thus make two groupings of Korean peninsula languages: the Han2 languages - spoken in Shilla and among the subjugated class in Paekche - and the Puyo-Koguryoic languages of Koguryo, Puyo (another Northern Korea state), and Paekche's ruling class. The latter family is now totally extinct and probably made a minor impact on modern Korean. The lack of written records and remaining vocabulary items from these languages make it difficult to learn much about the nature of the "Koguryoic" family.
There are, however, two sets of Chinese records that list words from the Koguryo language. Beckwith identifies thirteen words ("Archaic Koguryo") contained in a 3rd century Chinese record about the language of the Koguryo people. The second record is the Samsuk Sagi, the "Three Kingdoms of Korea" work that includes a record of a king in 755 changing all the place names in Korea into Chinese. The older toponyms in the Koguryoic areas do not resemble modern day Korean, and despite some controversy of whether the names were given by the Koguryo people or by other peoples populating the area before their arrival, Beckwith shows that a match between these and the Archaic Koguryo lexical items strongly suggest that the toponyms are from the "Old Koguryo" language. For many of these Koguryo place names, the record shows a Chinese transcription of the word's pronunciation as well as a meaning for the word. Beckwith identifies around 130 distinct Old Koguryo words from this document.
Scholars have known about these Koguryo lexical items for almost a century now, but the main problem has been reconstructing the proper Chinese pronunciation of the era in which the words were transcribed. There have been many improvements upon this knowledge in recent years, and Beckwith employs this new understanding of old Chinese to reconstructing many of these Koguryo words with more accuracy than before.
For examples of the close relation of some Koguryo words and Old Japanese, download this 2-page PDF. Almost all scholars agree that the language contained in this "Koguryo" set looks much like Old Japanese. Roy Andrew Miller - who is famously convinced that Japanese is an Altaic language - believed these words to be Proto-Japanese from Wa people who were living on the peninsula. There, however, is no evidence of a Proto-Japanese/Wa conquest in Korea that could have caused a change in place names. An important side note, which Beckwith emphasizes in the paper, Korean words look absolutely nothing like the Koguryo vocabulary, and the weakness of this connection puts the Japanese-Korean relation theory in doubt.
If the Japanese (Wa/Yayoi) and Koguryo/Paekche peoples are truly related, how in the world did they get all the way through the Korean peninsula and down to Japan which there is no record of happening? They didn't. Based on the work of Gisaburo N. Kiyose, Beckwith proposes a somewhat radical immigration narrative for the Wa. He puts the original Koguryoic homeland in Liao-Hsi (present day Liaoning) on the coast of Northeast China. Once the Chinese put pressure on this racial group, the more nomadic and warlike Puyo-Koguryo peoples (who had already split from the Wa at this point) made their way up to Korea and Manchuria. The Wa - who were mostly fishermen and farmers - left by boat to Korea, Kyushu, and the Ryukyuan islands at the same time. Archaeologists have artifacts that show a connection between the Yayoi culture and the culture of that period on the peninsula, and Beckwith suggests that this does not necessarily mean a voyage from settlements in Korea to Japan but a simultaneous settlement of both areas. He also re-emphasizes that no traces of this farming culture can be found in Manchuria or North Korea - which would be critical to proving Japanese came from Northeast Asia as the Altaic family theory would suggest.
Is there evidence for the proto-Japanese presence in China? First of all, Beckwith identifies a set of "native" Japanese words clearly derived from Chinese - with ume (plum) and uma (horse) being the most obvious. (Plums and horses are not even native to the Japanese archipelago.) Furthermore, the Mongolic Hsien-pei captured "people from Wa" in 178 A.D. near the present day Lao-ha River in China, meaning the Proto-Japanese still lived in China during the Yayoi period. In the original accepted theory that continental Koreans came to Japan to spread Yayoi culture, they came by boat. Why could the Wa have not originally come to Korea, Japan, and the Ryukyu islands by boat from somewhere other than the Korean peninsula?
Surely trained linguists and archaeologists will be able to find holes in Beckwith's theory that I do not see (here's one criticism), but the closer resemblance of Japanese to Koguryo than Shilla-based Korean puts a serious dent into the basic idea that the Japanese and Korean peoples are "related." For example, in Jared Diamond's essay on the roots of the Japanese people, he comes to the conclusion that:
As reluctant as Japanese and Koreans are to admit it, they are like twin brothers who shared their formative years. The political future of East Asia depends in large part on their success in rediscovering those ancient bonds between them.
Beckwith's theory pretty much puts the Japanese and Koreans as distant relatives - cousins at best and definitely not the "brothers" as Diamond would like them to be. Even if Koguryo and Paekche peoples were subsumed into the "Korean people," they did not add much to the linguistic tradition. Beckwith talks about the fact that Koguryo may have been going extinct even before the fall of the kingdom since so many of the inhabitants spoke a Han Korean language. Once T'ang China took over Koguryo, they exiled many of the Koguryo people to the middle of China to die off there.3 At best, the modern day Koreans have a minority strain of Koguryo in their DNA and language. The means that the Japanese people's cousins - Koguryo and Paekche peoples - happened to be the uncle in a big Korean family mostly made up of Han peoples. The Wa, therefore, have no blood relations to the Shilla side of the family and were never themselves "continental Koreans." Before and after the fall of Paekche in 660, many Paekche elites fled to Japan. In fact, one-third of the nobility in Nara (in the Nara period) was "foreign" - which I assume to mean Paekche Koreans. Although this complicates the "racial purity" of the Japanese today, this still does not make the Japanese people directly related to the majority ancestor of Koreans.
Here is the small dictionary of Old Japanese and Koguryo words:http://www.msu.edu/~...bs.Beckwith.pdf