Related Experiment Video
Updated: Aug 13, 2026

Live Cell Imaging of Chromosome Segregation During Mitosis
Published on: March 14, 2018
Anaphase lagging mainly explains chromosomal mosaicism in human preimplantation embryos
Edith Coonen1, Josien G Derhaag, John C M Dumoulin
1Research Institute Growth & Development (GROW), Maastricht University and Department of Obstetrics & Gynaecology, Academic Hospital Maastricht, The Netherlands. eco@sgyn.azm.nl
Background:
Cleavage stage embryos as well as postimplantation embryos have been studied extensively over the years. However, our knowledge with respect to the chromosomal constitution of human embryos at the blastocyst stage is still rudimentary.
Methods:
In the present paper, a large series of human blastocysts was examined by means of fluorescent in situ hybridization (FISH).
Results:
It was found that only one in four blastocysts (25%) displayed a normal chromosomal pattern. We defined a group of blastocysts (26%) displaying a simple mosaic chromosome pattern (different cell lines resulting from one chromosomal error), an about equally large group of blastocysts (31%) displaying a complex mosaic chromosome pattern, and a smaller group of blastocysts (11%) showing a chaotic chromosome distribution pattern. Six per cent of all blastocysts analysed could not be assigned one of the previously mentioned chromosomal patterns.
Conclusion:
Anaphase lagging appeared to be the major mechanism through which human embryos acquire a mosaic chromosome pattern during preimplantation development to the blastocyst stage.
Related Concept Videos
Meiosis II
Nondisjunction
Meiosis I
Prophase I is the most extended and complex step of meiosis I characterized by synapsis, chromosome pairing, and recombination of the homologous chromosomes. This process is facilitated by a proteinaceous structure called the...
Meiosis II
The timing and cell division patterns of meiosis differ between males and females. In male meiosis, the centrosomes are part of the formation of the meiotic spindle. However, in oocytes, including that of humans, Drosophila,...
Meiosis vs. Mitosis
Before the start of mitosis and meiosis I, the cell synthesizes DNA, resulting in two homologous copies of each chromosome. DNA synthesis is...
Nondisjunction

