I have noticed several inaccuracies in hhug's post, which I will proceed to point out below.
QUOTE (hhug @ Feb 7 2008, 04:08 PM)

25% of Japanese are of the Haplogroup O2b marker. This is also the most common marker found in Koreans.
First, 25% is a
low (in other words, "conservative") estimate of the frequency of haplogroup O2b among Japanese. In fact, 25% is the lowest frequency of haplogroup O2b I have ever encountered in any published study of Japanese Y-chromosome DNA. The frequency of haplogroup O2b among most Japanese samples is over 30%.
Second, haplogroup O2b is generally not the most common Y-DNA haplogroup found among Koreans. The frequency of haplogroup O3-M122 exceeds the frequency of haplogroup O2b among the samples of Koreans that have been analyzed for most published studies of Korean Y-chromosome diversity. For example, Wells et al. (2001) "The Eurasian Heartland: A continental perspective on Y-chromosome diversity" found haplogroup O3-M122 in 36%, haplogroup O*(xO1a-M119, O2a-M95, O3-M122) in 31%, and haplogroup O1a-M119 in 4% of a sample of 45 Koreans. Even if all the O*(xO1a, O2a, O3) were actually haplogroup O2b, the frequency would still be only 31%, which is less than the 36% of this sample who belonged to haplogroup O3-M122. Results from other studies, which sampled larger numbers of Koreans, are as follows:
Xue et al., "Male demography in East Asia: a north-south contrast in population expansion times":
19/68 = 28% haplogroup O2b
27/68 = 40% haplogroup O3
(Note that the 68 Korean samples of Xue et al. include both South Koreans (hanguk-saram) and Koreans in China (chaoxian-zu).)
Hammer et al., "Dual Origins of the Japanese: Common Ground for Hunter-Gatherer and Farmer Y-chromosomes":
28/75 = 37% haplogroup O2b
30/75 = 40% haplogroup O3
(Note that the 75 Korean samples of Hammer et al. were all obtained from South Korean subjects.)
Kim et al. (2007), "Lack of Association between Y-Chromosomal Haplogroups and Prostate Cancer in the Korean Population":
29/110 = 26% haplogroup O2b
50/110 = 45% haplogroup O3
Hong, S. B., Jin, H. J., Kwak, K. D., Kim, W. (2006), "Y-chromosome Haplogroup O3-M122 Variation in East Asia and Its Implications for the Peopling of Korea":
31/154 = 20% haplogroup O2b
65/154 = 42% haplogroup O3
As you may see in the above results, the proportion of haplogroup O2b among samples of Koreans has tended to be negatively correlated with the sample size; in other words, the trend in studies of Korean Y-DNA is to find lesser percentages of haplogroup O2b in studies with larger sample sizes, and the frequency of the various haplogroups among larger samples should approach the true frequency of haplogroup O2b among the entire Korean population. The studies that have taken small samples (e.g. Wells et al. 2001) have probably overestimated the frequency of haplogroup O2b among Koreans. In contrast, the frequency of haplogroup O3 has tended to be positively correlated with sample size, which means that the true frequency of haplogroup O3 among the entire Korean population is likely to be at the higher end of the estimates (e.g., higher than 40%). The true frequency of haplogroup O2b among Koreans is likely somewhere between 20% and 30%. Thus,
haplogroup O3-M122 is clearly the predominant Y-chromosome haplogroup among Korean males, and hhug's claim that haplogroup O2b is the most common Y-chromosome haplogroup among Koreans is
false.
Third, haplogroup O2b does not represent a homogenous group; the haplogroup O2b Y-chromosomes found among Koreans are mostly not of the same type as the haplogroup O2b Y-chromosomes typically found among Japanese. Among Koreans who belong to haplogroup O2b, about 4/5 of the haplogroup O2b Y-chromosomes belong to the O2b1*(xO2b1a) clade, while only about 1/5 (or even fewer) of the Korean haplogroup O2b Y-chromosomes belong to the O2b1a clade. On the other hand, among Japanese who belong to haplogroup O2b, the proportions are reversed; about 4/5 (or more) of the haplogroup O2b Y-chromosomes among Japanese belong to the O2b1a clade, while only 1/5 (or fewer) of Japanese haplogroup O2b Y-chromosomes belong to the O2b1*(xO2b1a) clade.
Fourth, although it is not often talked about, both the Korean type of haplogroup O2b (i.e. haplogroup O2b1*) and the Japanese type of haplogroup O2b (i.e. haplogroup O2b1a) are found among some populations in Southeast Asia. Haplogroup O2b (including the typically Japanese subclade, O2b1a) has been found in approximately 5% of several samples of populations in Thailand and Vietnam, for example. Besides the typically Korean haplogroup O2b1*(xO2b1a) and the typically Japanese haplogroup O2b1a, there exists yet another type (or types) of haplogroup O2b, namely haplogroup O2b*(xO2b1), which has been found at low frequency (<5%) among indigenous populations of Manchuria and Korea. Frankly speaking, at the present state of research, the origin, diversification, and dispersal of haplogroup O2b Y-chromosomes all remain uncertain.
QUOTE
20% of Japanese are of the Haplogroup O3 marker. Overwhelmingly, most of the O3 markers found among the Japanese are of the O3a5 subclade. it is also the most common one found among Han Chinese today.
hhug has gotten one thing right: most of the haplogroup O3 Y-chromosomes found among Japanese samples belong to the O3a5 subclade. In fact, most Japanese haplogroup O3 Y-chromosomes can be defined all the way to haplogroup O3a5a-M117. Besides the Japanese, haplogroup O3a5a-M117 Y-chromosomes are the most common type of haplogroup O among the Tibetans and some other populations of western China, including western Mongol groups. In eastern China, and particularly in southeastern China, haplogroup O3*(xO3a5) is more common than haplogroup O3a5 or haplogroup O3a5a. In Korea, haplogroup O3a5 and haplogroup O3*(xO3a5) are distributed rather evenly, each accounting for about 50% of Korean haplogroup O3, but haplogroup O3a5a is not particularly common in Korea, as most Korean haplogroup O3a5 Y-chromosomes are O3a5-M134*(xO3a5a), and thus do not belong to the typically Japanese and Tibetan subclade, haplogroup O3a5a-M117. In case you were wondering, the haplogroup O3 Y-chromosomes found among Austronesians are mostly haplogroup O3-M122*(xO3a5); haplogroup O3*(xO3a5) is actually the most common haplogroup among Filipinos, and the second most common haplogroup among Polynesians. Haplogroup O3 Y-chromosomes among the Tibeto-Burman-speaking populations of India and Burma, on the other hand, are almost entirely haplogroup O3a5 (and especially haplogroup O3a5a), just like the Tibetans and Japanese. Thus, there seems to be a sort of Tibeto-Burman-Japanese ("Western China"?) linkage versus a Sino-Austronesian ("Eastern China"?) linkage in the distribution of haplogroup O3, while Koreans (and most other so-called "Altaic" groups, actually, as well as some samples of Han from North China) occupy an ambiguous, intermediate position, close to the Hmong-Mien groups, in regards to the subtypes of haplogroup O3 Y-chromosomes found among them.
However, the two other claims that hhug has made in regards to haplogroup O3 are questionable. For one, 20% is a rather high estimate of the frequency of haplogroup O3 among Japanese; the true frequency of haplogroup O3 among Japanese is likely to be somewhere between 15% and 20%. For another, haplogroup O3a5 is probably not the most common type of haplogroup O3 found among modern Han Chinese; Bo Wen et al.'s study of Han Chinese populations from North and South China, for example, found haplogroup O3*(xO3a5) to be the most common type of haplogroup O3, and overall the most frequently occurring haplogroup, among Han Chinese, especially in southern China. Xue et al. also found haplogroup O3*(xO3a5) to be most common among Han in southern China, whereas both O3*(xO3a5) and O3a5 are equally common among Han in northern China.
QUOTE
4% of Japanese are of the Haplogroup O1 marker. This marker is found among the non-Han southern ethnic groups (ie Austronesian, Austroiloid, etc.). About 10% of southern Han in southern Jiangsu, Zhejiang, Fujian, Guangdong, Guangxi also have this marker. Undoubtedly this was the original genetic marker of Wu-Yue and Bai-Yue people.
False. Provide sources for the figure of 4% haplogroup O1 among Japanese. According to reputable published sources, including Hammer et al.'s "Dual Origins of the Japanese" study, haplogroup O1 is
completely absent from the Japanese population. Again, this is similar to the Tibetans, among whom haplogroup O1 is practically nonexistant.
And haplogroup O1 (which is almost always actually haplogroup O1a-M119) is not common among Australoids; it is only common among Austronesians (particularly Taiwanese Austronesians, AKA Formosans), Tai-Kadai peoples (particularly the Hlai/Li people of Hainan), and eastern/southern Han Chinese (particularly those in the region of the Yangtze river delta and around the southern coast of China). Thus, it can be said that haplogroup O1 is typical of Mongoloid populations of the eastern and southern coasts of China and nearby islands, such as Taiwan, the Philippines, Hainan, and parts of Indonesia.
I suspect that hhug has confused haplogroup O1 with haplogroup O2a-M95, which actually
is found in a minority (approx. 4% or less) of Japanese samples. Haplogroup O2a-M95 is related to the haplogroup O2b Y-chromosomes that are much more common among the Japanese. The peak frequencies of haplogroup O2a are found among Austroasiatic-speaking tribal populations of India, such as the Juangs (aboriginal inhabitants of Orissa, India) and the Nicobarese (aboriginal inhabitants of the Nicobar Islands, just south of the Andaman Islands), who are both 100% haplogroup O2a.
QUOTE
Basically, half of Yayoi Japanese originated from Koreans and the other half came from Chinese (Han and Wu-Yue).
This is completely unsubstantiated conjecture. hhug's claims do not merit much consideration.