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We report a DNA-gold nanoparticle (AuNP) hybrid hydrogel in which the AuNPs crosslink enzymatically synthesized DNA to form a gel network. PCR-elongated DNA and AuNPs act as a one-dimensional polymer and cross-linkers, respectively. The DNA-AuNP hydrogel has the functional properties of both long DNA and the AuNPs.

We propose a hypothesis of ploidy elevation in the androgenetic clam Corbicula fluminea, based on an abnormal process of fertilization in clams collected at the Tone River, Ibaraki Prefecture, Japan. Most eggs showed androgenesis, that is, extrusion of all maternal chromosomes as two polar bodies during the first meiotic division. Most eggs did not form a female pronucleus, but only a male pronucleus. However, some eggs proceeded to the second meiosis and formed both a female and a male pronucleus. The formation of the female pronucleus suggests the hypothesis that ploidy elevation in androgenetic clams may have occurred by aberrant meiosis due to an altered orientation of the meiotic spindle.