Development of a Real‐Time PCR‐Based Method for Analyzing Semen‐Specific Unmethylated DNA Regions and Methylation Status in Aged Body Fluid Stains

The detection of semen in forensic investigation is considered important evidence of sexual assault. In this study, we report the development of a real‐time polymerase chain reaction‐based method for identifying semen that can simply and rapidly analyze the semen‐specific unmethylated region of the DACT1 gene. Using two fluorescent probes designed for the methylated or unmethylated status, this method could perform quantitative analysis of the methylation status in this region. Furthermore, this method was used to analyze various body fluid samples, including 29‐year‐old semen and blood stains. The results showed that this method can detect almost exclusively semen or nonsemen signals even in highly decomposed samples, while a few semen or nonsemen samples showed slight signals of the other fluorescence probe. Although there is still a need for further analysis such as setting thresholds to analyze unknown samples, this method could be a useful supplementary tool for identifying semen, especially in old stains such as those in cold‐case investigations.     

Swedish Diplomacy in the Asia-Pacific Region

The year 2018 marks the 150th anniversary of the establishment of diplomatic relations between Japan and Sweden. It is believed that the first contact between Sweden and Japan came during the Edo Period and was mediated by the Netherlands. The Treaty of Friendship, Commerce and Navigation between Japan and Sweden, signed in 1868, also came into being thanks to the good offices of the Dutch. This treaty, like many others into which Japan entered at that time, was an “unequal treaty.” As Japan increased its presence in East Asia, this unequal treaty with Sweden was revised in 1911. The world was changing. Sweden and Japan shared a common interest in opposing Russia’s ambitions. Russia in particular was a common threat to the diplomatic posture and security of both Japan and Sweden. These two nations, positioned like bookends on either side of Russia, could be important strategic partners for one another and allies in their relationships with Russia. Considering the current issue of North Korea, Sweden also has the potential to act as a mediator because it maintains diplomatic relations with North Korea. There is reason to believe that the diplomatic relationship between Japan and Sweden will develop further.