Our whole lives we have been taught there are only two forms of cell division; mitosis and meiosis cell division. Mitosis results in two identical daughter cells, creating body or somatic cells. Meiosis results in four sex or gamete cells, each genetically unique.
Diagram courtesy of Technology Networks
One of the reasons I love this field is because of how rapidly it developed.
On April 27, Nature, a prestigious science journal, published a revolutionary paper. Researchers at the Institute of Cellular and Organismic Biology, Academia Sinica were studying zebrafish skin cells. They used a multicolor cell membrane tagging system(shown below) which allowed them to track and record development. While tracking the cell division of the zebrafish the team noticed each cell would divide into a maximum of four cells in its lifetime. However, the cells did not divide via mitosis. Instead, each cell division caused an absence of DNA in the progeny cells, with up to 50% of the genome disappearing. This new form of cell division was coined 'asynthetic fission' and is believed to be effective at quickly covering large areas.
Asythetic fission is a cheaper form of cell division, requiring less energy. There were, however, recorded instances where cells in asythetic fission were unable to fully split. These cells merged together, keeping their genome intact.
It is speculated that this new, fascinating form of cell division may occur in other organisms, other than zebrafish. Personally, I am in awe researchers were able to disprove notions taught in schools for so long. It goes to show how much more there is to learn about organisms and the world around us.
References
Chan, K.Y., Yan, CC.S., Roan, HY. et al. Skin cells undergo asynthetic fission to expand body surfaces in zebrafish. Nature605, 119–125 (2022). https://doi.org/10.1038/s41586-022-04641-0
Mitosis vs. meiosis: Key differences, chart and Venn diagram. Cell Science from Technology Networks. (n.d.). Retrieved May 31, 2022, from https://www.technologynetworks.com/cell-science/articles/mitosis-vs-meiosis-312017