2024-03-29T00:31:55Zhttps://eprints.lib.hokudai.ac.jp/dspace-oai/requestoai:eprints.lib.hokudai.ac.jp:2115/734202022-11-17T02:08:08Zhdl_2115_20049hdl_2115_141Intra-ooplasmic injection of a multiple number of sperm to induce androgenesis and polyploidy in the dojo loach Misgurnus anguillicaudatus (Teleostei: Cobitidae)Yasui, George ShiguekiSaito, TaijuZhao, YanFujimoto, TakafumiYamaha, EtsuroArai, KatsutoshiFertilizationFishICSIPronucleusSpermatozoa660Polyspermy was initiated by microinjecting a multiple number of sperm into the activated and dechorionated eggs of dojo loach Misgurnus anguillicaudatus (Teleostei: Cobitidae). A 10-nL sperm suspension from an albino (recessive trait) male (105, 106, 107, or 108 sperm mL-1) was microinjected into eggs from a wild-type female. Although the rates of embryos developing into the blastula stage in the injection group at the highest sperm concentration were similar to that of the control group, the hatching rates of the injection group were much lower. A large proportion of embryos that developed from the injected eggs were haploid and mosaics containing haploid cells. Most of the haploid and mosaic embryos inherited only paternally derived alleles in the microsatellite markers (i.e., androgenesis was initiated by injecting multiple sperm). In contrast, some haploid embryos contained both paternal and maternal alleles despite haploidy, suggesting that they were mosaics consisting of cells with either paternal or maternal inheritance. The injected eggs displayed diploid, hypotriploid, and triploid cells, all of which included both maternally and paternally derived alleles. One albino tetraploid with only paternal alleles was also observed from the injected eggs. These results suggest that part of the sperm microinjected into the ooplasm should form a male pronucleus(-i), which could develop by androgenesis or could fuse with the female pronucleus(-i). Thus, microinjecting multiple sperm is considered a potential technique by which to induce androgenesis and polyploidy.Cambridge University PressJournal Articleapplication/pdfhttp://hdl.handle.net/2115/73420https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/73420/1/Zygote_26%285%29_408.pdf0967-1994Zygote2654084162018-10enginfo:doi/10.1017/S0967199418000448This article has been published in a revised form in Zygote https://doi.org/10.1017/S0967199418000448. This version is free to view and download for private research and study only. Not for re-distribution, re-sale or use in derivative works. © copyright holder.author