In a study published in the journal Development cell, CRCHUM researcher Greg FitzHarris and Aleksandar Mihajlovic, postdoctoral fellow in his laboratory and first author of the study, reveal in aged mouse eggs (oocytes) that certain chromosomes are slower to move during meiosis, a crucial phase of cell division.
These laggards contribute to an uneven chromosome distribution and therefore to the formation of cells with an abnormal number of chromosomes. This abnormality, called aneuploidy, is one of the main causes of infertility and, in part, explains why older women have difficulty getting pregnant and carrying a pregnancy to term.
To give the slower chromosomes time to reach their destination, we artificially prolonged meiosis with a chemical. Using high-definition imaging techniques, we found that this slowing down before cell division limited aneuploidy. “
Greg FitzHarris, professor, University of Montreal
In the medium term, this discovery, still at the stage of basic research and carried out in the laboratory on mice, could be used in the clinic to increase the performance of the eggs used during in vitro fertilization. Thorough testing of effectiveness, safety and security will be necessary before adopting such an approach.
Almost one in six Canadian couples are affected by infertility. This number has doubled since the 1980s.
Mihajlovic, IA, et al. (2021) Distinct classes of late chromosomes underlie age-related oocyte aneuploidy in mice. Development cell. doi.org/10.1016/j.devcel.2021.07.022.