Testing the applicability of environmental DNA metabarcoding to landscape genetics.

Landscape genetics is a field dealing with local genetic differences and contributes to strategic conservation planning. Recently, environmental DNA (eDNA) metabarcoding has proven useful not only for detecting species but also for assessing genetic diversity and genetic structure on a large scale such as in phylogeography. However, it remains unclear whether eDNA analysis also has sufficient power to perform the landscape genetics, which focuses on a local scale. To reveal the applicability of eDNA to landscape genetics, we conducted an eDNA metabarcoding analysis of the mitochondrial DNA D-loop region of the fluvial sculpin Cottus nozawae in the upper Sorachi River in Japan and compared the results with inferences based on traditional tissue-based approaches by the same D-loop region and genome-wide SNP data. As a result, the spatial distribution of haplotypes was generally consistent between the eDNA- and tissue-based approaches. In addition, the genetic differentiation statistics calculated using eDNA and tissue samples were highly correlated when comparing both in the D-loop region. The removal of low-frequency reads or the conversion to semi-quantitative rankings of eDNA data did not alter the correlation of genetic diversity and differentiation statistics with tissue-based approaches much. Finally, we confirmed that analyses using eDNA data can reveal patterns such as isolation-by-distance shown in previous studies on this species, indicating the applicability of eDNA to basic landscape genetics. Even though some limitations remain, eDNA may have great potential for conducting basic landscape genetics.

A strategic sampling design revealed the local genetic structure of cold-water fluvial sculpin: a focus on groundwater-dependent water temperature heterogeneity.

A key piece of information for ecosystem management is the relationship between the environment and population genetic structure. However, it is difficult to clearly quantify the effects of environmental factors on genetic differentiation because of spatial autocorrelation and analytical problems. In this study, we focused on stream ecosystems and the environmental heterogeneity caused by groundwater and constructed a sampling design in which geographic distance and environmental differences are not correlated. Using multiplexed ISSR genotyping by sequencing (MIG-seq) method, a fine-scale population genetics study was conducted in fluvial sculpin Cottus nozawae, for which summer water temperature is the determinant factor in distribution and survival. There was a clear genetic structure in the watershed. Although a significant isolation-by-distance pattern was detected in the watershed, there was no association between genetic differentiation and water temperature. Instead, asymmetric gene flow from relatively low-temperature streams to high-temperature streams was detected, indicating the importance of low-temperature streams and continuous habitats. The groundwater-focused sampling strategy yielded insightful results for conservation.

Isolation and characterization of microsatellites from a cicada, Yezoterpnosia nigricosta (Hemiptera: Cicadidae), distributed in subarctic and cool temperate forests.

The cicada Yezoterpnosia nigricosta (Hemiptera: Cicadidae) is distributed in subarctic and cool temperate forests in Japan, China and the Russian Far East. Due to its limited and isolated distribution at higher altitudes in cool temperate forests on the main island of Japan, especially in the central and southern areas, this species is listed as a threatened or near-threatened species on the Red List of 12 prefectures in Japan. Moreover, there are concerns about the impacts of climate change on the species' distribution and population demography. In this study, seventeen microsatellite markers were developed for Y. nigricosta, and marker suitability was evaluated using 32 individuals from two populations in Nagano prefecture (central Japan) and Hokkaido, a northern island of Japan. The number of alleles, expected heterozygosity and fixation index at each locus were 1-15 (mean = 4.294), 0.000-0.914 (mean = 0.519) and -0.225-0.456 (mean = 0.108), respectively. Furthermore, there was moderate genetic differentiation between the two populations (FST = 0.111, F'ST = 0.237). These markers will be useful to evaluate the genetic structure and to infer population demographic history of Y. nigricosta populations, which can contribute to population genetics studies of this species.

Occurrence of cardiovascular events after the 2011 Great East Japan Earthquake and tsunami disaster.

There are conflicting reports regarding the occurrence of cardiovascular events after a major earthquake. To understand the impact of the Great East Japan Earthquake on cardiovascular events, we retrospectively examined the clinical records prepared by emergency room physicians between 2009 and 2011 (n = 66,244), and compared the occurrence of these events between 2011 and 2009, and 2011 and 2010. There was a significant increase in the number of patients with cardiovascular events during the 3 week period after the earthquake in 2011 (n = 106) compared with that during the same period in 2009 (n = 72) or 2010 (n = 65) (P = 0.002). The number of patients with acute coronary syndrome or congestive heart failure in March 2011 was significantly increased compared with 2009 or 2010, however, there were no significant increases in 2011 in other cardiovascular events including stroke, aortic dissection, pulmonary thromboembolism, or out-of-hospital cardiac arrest compared with 2009 or 2010. These findings suggest that the incidence of cardiovascular events may have been heterogeneous after the disaster.