Chiba Prefectural Museum of Art

Recent genetic advancements offer new opportunities for studying natural history museum collections. The genetic analysis of century-old aquatic animal specimens, mostly preserved in ethanol, can provide valuable insights into the changes in genetic diversity caused by anthropogenic impacts. However, knowledge of the characteristics of degraded DNA from such specimens remains limited. In this study, we evaluated the DNA quality of bitterling fish, Tanakia lanceolata (Temminck and Schlegel), collected during the Vega Expedition in Japan in 1879 and preserved in ethanol. We then performed genomic analysis to test its hypothesized translocation-involved population history. The historical DNA was degraded, peaking around 50 bp, but a minor fraction exceeded 300 bp. Mitochondrial genetic analysis revealed high genetic similarity between the eastern and western sides of the Central Highland, typically impeding the dispersal of primary freshwater fish. These findings suggest an unexpected dispersal ability in T. lanceolata or undocumented translocations before the large-scale domestic translocations recorded since the 1910s. The customized workflow for historical ethanol-preserved specimens, based on historical DNA quality in this study, provides a foundation for studying historical archives.

Abstract We investigated surface carbonate sediments at 33 sites on the outer shelf and slope around New Caledonia (163°–167°E, 20°–23°S), at water depths of 75–720 m. Four carbonate sedimentary facies are recognized on the basis of sediment size fractions and predominant constituents: Facies 1, encrusted grains (rhodoliths and macroids), bryozoa, and benthic foraminifera; Facies 2, bryozoa, benthic foraminifera, and mud; Facies 3, plankton and mud; and Facies 4, ahermatypic corals. Facies distributions were constrained primarily by water depth, and secondarily by local seafloor geomorphology that, in some areas, allows transport of sediments to deeper water. Because the dominant facies (Facies 1 and 3), as well as lagoon and basin facies, are distributed worldwide at similar latitudes, facies around New Caledonia can be considered as representative of carbonate sedimentary facies distributed in tropical–subtropical regions.