Mapping Human Genetic Diversity on the Japanese Archipelago - Assignment Example

Ding, Liang-Qi, Wao, Chuan-Chao, Farina, E. Sara, and Li, Hu. “Mapping Human Genetic Diversity on the Japanese Archipelago”. Advances in anthropology 1.2 (2011): 19-25.Web. Article Analysis This paper strives to give an analysis of the article by Ding, Liang-Qi, Wao, Chuan-Chao, Farina, E. Sara, and Li, Hu, which is titled “Mapping Human Genetic Diversity on the Japanese Archipelago” and published in Advances in anthropology 1.2 (2011): 19-25. The article explores the origin and diversification of East Asian populations, specifically the Japanese people. The origin of the current population on the island of Japan remains unclear to date (Ding et al. 1). According to archeological evidence, “there might have been two waves of migration to the Japanese archipelago in prehistory: the Paleolithic and Neolithic Jomonese and the Aeneolithic Yayoiese” (Ding et al. 1). However, Ding et al. affirm that the contributions of these two groups to the “contemporary Japanese population remain unclear” (1). Ding et al.’s work anticipates providing evidence from human genetics as a new approach to addressing this topic. Ding et al.’s research specifically examines the Japanese human population, a key contributor to East Asian populations. The migration of the Japanese population to their present island remains debatable, a feature that inspired Ding et al. to carry out this research. The investigation carried out by Ding et al. anticipates shading more light on the origin of the Japanese population. Japan forms a substantial proportion of the East Asian population. Controversy still rages as to how the Japan population arose. Two major waves of migration to the Japanese archipelago in prehistory have been proposed. Despite the fact that other theories exist, this research focused on the two major ones. “The first wave of migration began 50,000 years BP and reached a climax about 10,000 years BP, giving rise to the Jomonese culture” (qtd. in Hisao et al., 1998 ). Considered as the most recent, “a second wave of migration traveled to the Japanese archipelago at 23,000 years BP, giving rise to the Yayoi culture” (Ding et al. 1). According to fossil records and human remains, the Yayoiese apparently dominated the Japanese archipelago finalizing their expansion at about 300AD (qtd. in Chard, 1974). However, “the evidence from cranial morphology does not support a complete replacement of the Jomonese by the Yayoiese” (qtd. in Hanihara, 1984). Several theories explaining the origin and diversification of the Japanese exist (qtd. in Mizoguchi, 1986). The research done by Ding et al. used DNA and Y chromosome analyses to conclude the origin of contemporary Japanese from both maternal and paternal lineages. Molecular anthropological evidence seems more reliable when compared to historical, archeological or osteological studies, since the genetic material used in molecular anthropology tends to be continuous and maintains its integrity as its passed on from generation to generation (Ding et al.1). Historical, archeological or osteological studies are unreliable. When compared to other materials used in molecular anthropology studies, “Y chromosome and mtDNA prove to be the most powerful because of their abundance and ease of extraction” (qtd. in Zhang et al., 2007). By combining Y chromosome single nucleotide polymorphisms (Y-SNPs) and Y-chromosome short tandem repeats (Y-STRs) information, none recombining region of Y chromosome (NRY) can be used to reveal the population migration and expansion history of modern human (Ding et al. 20). Studies have also shown that mtDNA has a maternal inheritance protocol and the population genetic characteristics of mtDNA resemble the NRY (Ding et al. 20). The investigation carried out by Ding et al. seems to present new data which support an existing theory. The research also re-analyzes existing data. The key objective aimed at illustrating the origin of the East Asian populations and specifically the Japanese people, using molecular anthropology. This can be seen from the researchers’ statement that “the Japanese people reflect some of the most important populations for studying the origin and diversification of East Asians populations” (Ding et al. 1). “The Minatogawa man found in Okinawa who is approximated to be close to 18,000 years old, is considered the oldest hominid remain in the Japanese archipelago” (qtd. in Matsu’ura, 2010). Morphological findings of Minatogawa I male skull suggest its closer to the Liujiang man from Guangxi, China than to the upper cave man of northern China (qtd. in Suzuki, 1984). This finding suggests that the Jomonese might be the direct descendants of Minatogawa man (qtd. in Hisao et al., 1989). The investigation done by Ding et al. found out that the Jomonese culture lasted from the final stage of the last ice age about 2300 years ago; and was distributed widely on the Japanese archipelago at its climax (Ding et al. 20). The Yayoiese was the second wave of migration to the Japanese archipelago, entering the Korean Peninsula around 2300 years BP and finishing its expansion at 3rd century AD (Ding et al. 21). These waves of migration could be classified into three models that represent different genetic contributions of Jomonese and Yayoiese to the Japanese population (Ding et al. 21). The replacement model suggests that “since the Yayoiese dominated the Japanese archipelago after 3rd century AD, the Jomonese genetic lineages were completely replaced by Yayoiese” (qtd. in Howells, 1966; Turner, 1976.). The second model referred to as the transformation model, “claims that the incoming Yayoiese did not affect the gene pool of the existing Jomonese; implying that the contemporary Japanese are the direct descendants of Jomonese with no contamination from the Yayoiese” (qtd. in Suzuki, 1981; Mizoguchi, 1986). The admixture model, on the other hand, “suggests the contemporary Japanese are an admixture of the Jomonese, Yayoiese populations and more recent migrants, which reflects the admixture of contemporary variations” (qtd. in Hanihara, 1981.). Evidences from Y chromosome and mtDNA analyses in Ding et al’s research showed some substantial degree of agreement with the admixture theory. “Halo groups C, D, O and N account for 98.9% of contemporary Japanese” (Ding et al. 21). “According to the full mitochondrial sequencing data, contemporary Japanese are closest related to Koreans, which consists with the migration from Korea and the following rapid expansion in the Yayoi and Kofun periods” (Ding et al.). Since the research by Ding et al. was based on molecular anthropology, understanding some molecular terminologies were somehow challenging. For example, I had to use the medical dictionary to comprehend terms like Y chromosome single nucleotide polymorphisms (Y-SNPs), Y- chromosome short tandem repeats (Y-STRs)-regions on the none combining region of the Y chromosome and mtDNA (mitochondrial DNA of the species under study). Both Y chromosome and mtDNA analyses are vital methodologies used in molecular anthropology. The authors of this article constantly cited the work done by Zhang, F, Zhang, P and Jin, L. “Genetic studies of Human Diversity in East Asia”. Philosophical Transactions of the Royal Society B 362 (2007): 987-995, that certainly gave them useful data. Zhang et al.’s work describes the genetic studies of human diversity in East Asia. Since the authors of this article concentrated on the molecular anthropology studies, they found Zhang et al.’s reference very crucial. The reference material gives a comprehensive coverage of the Y chromosome and mtDNA analyses in the two migration waves that the authors relied upon. I chose this article because it provides useful information on molecular anthropology studies of the Japanese people. The article written by Zhang et al. remains useful to individuals who aspire to understand the origin of the Japanese. Work Cited Ding, Liang-Qi, Wao, Chuan-Chao, Farina, E. Sara, and Li, Hu. “Mapping Human Genetic Diversity on the Japanese Archipelago”. Advances in anthropology 1.2 (2011): 19-25. Web. 25 Jan. 2012 Read More