Radiocarbon age of a Holocene terrace of the Chikoi River at the Russia-Mongolia Border

A well-developed terrace was identified along the Chikoi River at the Russia-Mongolia border. The terrace deposits consist of massive fine sands of more than 8 m with numerous organic-rich paleosol horizons. Resulting radiocarbon ages for paleosol horizons suggest that floodplain emergence and terrace formation occurred in the early Holocene

Microarray analysis of promoter methylation in lung cancers

Aberrant DNA methylation is an important event in carcinogenesis. Of the various regions of a gene that can be methylated in cancers, the promoter is the most important for the regulation of gene expression. Here, we describe a microarray analysis of DNA methylation in the promoter regions of genes using a newly developed promoter-associated methylated DNA amplification DNA chip (PMAD). For each sample, methylated Hpa II-resistant DNA fragments and Msp I-cleaved (unmethylated + methylated) DNA fragments were amplified and labeled with Cy3 and Cy5 respectively, then hybridized to a microarray containing the promoters of 288 cancer-related genes. Signals from Hpa II-resistant (methylated) DNA (Cy3) were normalized to signals from Msp I-cleaved (unmethylated + methylated) DNA fragments (Cy5). Normalized signals from lung cancer cell lines were compared to signals from normal lung cells. About 10.9% of the cancer-related genes were hypermethylated in lung cancer cell lines. Notably, HIC1, IRF7, ASC, RIPK3, RASSF1A, FABP3, PRKCDBP, and PAX3 genes were hypermethylated in most lung cancer cell lines examined. The expression profiles of these genes correlated to the methylation profiles of the genes, indicating that the microarray analysis of DNA methylation in the promoter region of the genes is convenient for epigenetic study. Further analysis of primary tumors indicated that the frequency of hypermethylation was high for ASC (82%) and PAX3 (86%) in all tumor types, and high for RIPK3 in small cell carcinoma (57%). This demonstrates that our PMAD method is effective at finding epigenetic changes during cancer

Genome-wide profiling of promoter methylation in human

DNA methylation in the promoter region of a gene is associated with a loss of that gene's expression and plays an important role in gene silencing. The inactivation of tumor-suppressor genes by aberrant methylation in the promoter region is well recognized in carcinogenesis. However, there has been little study in this area when it comes to genome-wide profiling of the promoter methylation. Here, we developed a genome-wide profiling method called Microarray-based Integrated Analysis of Methylation by Isoschizomers to analyse the DNA methylation of promoter regions of 8091 human genes. With this method, resistance to both the methylation-sensitive restriction enzyme HpaII and the methylation-insensitive isoschizomer MspI was compared between samples by using a microarray with promoter regions of the 8091 genes. The reliability of the difference in HpaII resistance was judged using the difference in MspI resistance. We demonstrated the utility of this method by finding epigenetic mutations in cancer. Aberrant hypermethylation is known to inactivate tumour suppressor genes. Using this method, we found that frequency of the aberrant promoter hypermethylation in cancer is higher than previously hypothesized. Aberrant hypomethylation is known to induce activation of oncogenes in cancer. Genome-wide analysis of hypomethylated promoter sequences in cancer demonstrated low CG/GC ratio of these sequences, suggesting that CpG-poor genes are sensitive to demethylation activity in cancer

[Special section on volcanic glass] ARCHAEOLOGICAL OBSIDIAN STUDIES IN HOKKAIDO, JAPAN: RETROSPECT AND PROSPECTS

Recent research has identified an extended exchange network in the Japan Sea Rim area extending over 3,000 km and including the mainland. This paper reviews current knowledge about obsidian studies in Hokkaido, a part of this region, and makes proposals for future research. The geology of Hokkaido and its 21 known obsidian sources are reviewed and results of chemical analyses of some sources described. Archaeological studies of exchange networks, exploitation patterns and site variation are described. Proposals for the direction of future studies include additional research on the location, geological history and characterization of obsidian sources and the use of new models concerning procurement range, mobility patterns and behavioural strategies

Toward an Understanding of Technological Variability in Microblade Assemblages in Hokkaido, Japan

Five decades of research history on the late Upper Paleolithic in Hokkaido (northern Japan) shows that microblade assemblages appeared by approximately 20,000 B.P. and that various microbiade technologies were developed during late Pleistocene. The empirically observed good association between the morphological features of lithic raw materials and the reduction sequences of microblade cores demonstrates that morphological features of procured lithic raw materials (i.e., size and surface condition), which were constrained by unique geological and geoarchaeological characteristics in Hokkaido, created remarkable variability in reduction methods of microblade technology. This implies that geoarchaeological perspective can contribute to understanding technological variability in microblade assemblages in northeastern Asia. KEYWORDS: Hokkaido, microblade, technological variability, geoarchaeology, oxygen isotope stage 2

Human responses to the Younger Dryas in Japan

The effect of the Younger Dryas cold reversal on the survival of Late Glacial hunter-gatherers in the Japanese Archipelago is evaluated, through a synthetic compilation of 14C dates obtained from excavated Late Glacial and initial Holocene sites (332 14C dates from 88 sites). The estimated East Asian monsoon intensity and vegetation history based on the loess accumulations in varved sediments and pollen records in and around the Japanese Archipelago suggest an abrupt change to cool and dry climate at the onset of Younger Dryas, coupled with the Dansgaard–Oeschger Cycles as recorded in Greenland. The chronometric placement of sites based on an assessment of 14C dates show that the site numbers decrease from the Bølling–Allerød to Younger Dryas and increase from the Younger Dryas to Preboreal. However, human population dynamics inferred from a site distribution analysis was little changed from the previous Bølling–Allerød and to the following Preboreal. Moreover, hunter-gatherers consistently employed ceramic pottery technology since its emergence prior to the onset of Younger Dryas, while the quantity of ceramic vessels that were undermined during the Younger Dryas dramatically increased at the onset of the Holocene, implying that a substantial change in hunter-gatherer socioeconomy occurred after the end of Younger Dryas

Tolbaga revisited: Scrutinizing occupation duration and its relationship with the faunal landscape during MIS 3 and MIS 2

Here we reexamine the occupational ages of the Tolbaga site, southwestern Transbaikal, Russia. With AMS14C dates from 23 bone samples, we conclude that the occupation ages of Tolbaga in lithostratigraphical unit II (cultural layer 4 in the previous literatures) of Tolbaga fall within the interval of 42,970 and 26,010 Cal yr BP. The age is consistent with occupation ages presented in previous papers, but with a slightly expanded time span. Further, the occupational ages newly presented here are divided into three sub-stages; from oldest to youngest, the first (older) section at 42,970–40,425 Cal yr BP, the second section at 37,785–33,290 Cal yr BP, and the third section at 29,320–26,010 Cal yr BP. These three sub-stages are placed at the onset of the Upper Paleolithic chronological sequences in southern Siberia; that is, the first section coincides with the Initial Upper Paleolithic (IUP), the second stage with the Early Upper Paleolithic (EUP), and the third stage with the Middle Upper Paleolithic (MUP). Further, the first section falls within the climatic amelioration period between the Heinrich (H) event 5 (H5: 46,000 Cal yr BP) and H4 (39,000 Cal yr BP), the second section is within the interval of H4 and H3 (30,000 Cal yr BP), and the third section within the interval of H3 and H2 (24,000 Cal yr BP). This suggests that occupations occurred once climatic conditions became relatively stable, although high-resolution reconstruction of the local natural environment needs future evaluation. Additionally, animal species in each section corresponds to specific landscape types; (1) the first section to the steppe or steppe-tundra, (2) the second section to a mosaic of landscapes including taiga (parkland forest), high-mountain steppe, dry-steppe and rocky canyon, and mountain-tundra, and (3) the third section to steppe or steppe-tundra again. This change in animal species composition implies temporal changes in faunal compositions within the natural environment and/or hunting strategies of the Tolbaga site occupants

Radiocarbon dates, microblades and Late Pleistocene human migrations in the Transbaikal, Russia and the Paleo-Sakhalin-Hokkaido-Kuril Peninsula

We compare late Pleistocene archaeological 14C databases from the Transbaikal, Russia and the Paleo-Sakhalin-Hokkaido-Kuril Peninsula (PSHK) to the appearance and disappearance of microblade technology for evidence of human migration. In the Transbaikal, we identify as many as three events at 24,830, 22,740, and ∼15,000 cal bp, respectively. On the PSHK, we see migration at ∼26,800, and likely again at ∼13,000 cal bp. We offer an explanation for the Last Glacial Maximum origin of northeast Asian microblades that reconciles several major points of current competing theories. The later migration signals in both areas are weaker and associated with terminal Pleistocene (Bølling-Allerød-Younger Dryas) environmental changes at the beginning of the Mesolithic Period in the Transbaikal and the Incipient-Jomon Period on PSHK. In the former, the second migration event may have been repopulation of an empty or sparsely inhabited area. In the latter, it appears to be population replacement when microblades completely disappear from the Peninsula without a reduction in the number of 14C dates