Related Experiment Video
Updated: Jun 13, 2026

Mouse Oocyte Microinjection, Maturation and Ploidy Assessment
Published on: July 23, 2011
A preliminary concept, deduced from cytogenetic analyses, for explaining different types of multipronuclear oocytes
1Department of Gynecology and Obstetrics, University of Ulm, Ulm, Germany. bernd.rosenbusch@uniklinik-ulm.de
Abstract:
Oocytes with three or more pronuclei and one or two polar bodies arising after intracytoplasmic sperm injection were analyzed cytogenetically, and the data were used to develop a general model explaining the possible origin of the abnormal pronuclear stages. The mechanisms, either separately or in variable combinations, that induce the appearance of additional pronuclei are: 1) nonextrusion of the second polar body; 2) incomplete chromatid segregation into the extruded second polar body; and 3) dispersal of the oocyte chromatids in the presence of the second polar body formation.
Related Concept Videos
Oogenesis
Oogenesis
Each primary oocyte is surrounded by a layer of pre-granulosa cells, forming what is known...
Meiosis II
Fertilization
What is Meiosis?
What is Meiosis?
Although meiosis shares similarities with mitosis—both rely on microtubules to...

