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Updated: Oct 5, 2025

Mouse Oocyte Microinjection, Maturation and Ploidy Assessment
Published on: July 23, 2011
Haploidy in somatic cells is induced by mature oocytes in mice
Yeonmi Lee1,2, Aysha Trout3, Nuria Marti-Gutierrez4
1Department of Biomedical Science, College of Life Science, CHA University, Seongnam, Gyeonggi, 13488, South Korea.
Abstract:
Haploidy is naturally observed in gametes; however, attempts of experimentally inducing haploidy in somatic cells have not been successful. Here, we demonstrate that the replacement of meiotic spindles in mature metaphases II (MII) arrested oocytes with nuclei of somatic cells in the G0/G1 stage of cell cycle results in the formation of de novo spindles consisting of somatic homologous chromosomes comprising of single chromatids. Fertilization of such oocytes with sperm triggers the extrusion of one set of homologous chromosomes into the pseudo-polar body (PPB), resulting in a zygote with haploid somatic and sperm pronuclei (PN). Upon culture, 18% of somatic-sperm zygotes reach the blastocyst stage, and 16% of them possess heterozygous diploid genomes consisting of somatic haploid and sperm homologs across all chromosomes. We also generate embryonic stem cells and live offspring from somatic-sperm embryos. Our finding may offer an alternative strategy for generating oocytes carrying somatic genomes.
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