Connecting the bonds that lead to multicellularity
Connecting the bonds that lead to multicellularity lead image
Multicellular organisms are incredibly diverse and have evolved independently many times. How the cells in such organisms connect affects their subsequent biology and evolution. Those intercellular bonds also present an intrinsic physics problem: physical forces and local interactions hold the cells together.
Combining evolutionary biology and physics, Day et al. reviewed the two categories of intercellular bonds in multicellular organisms.
Reformable bonds act like Velcro, with sticky proteins adhering to each other as cells bump around. These bonds can attach and detach again and again. In contrast, non-reformable bonds occur only once. For example, as cells undergo division, the daughter cell may not completely separate from the parent, creating a bond that, when broken, cannot be recreated.
The team provided an overview of the natural history of these bonds and described where each type can be found. Reformable bonds are common in animals, but non-reformable bonds are typical in many complex organisms like plants, fungi, and algae.
“We hope this will be useful if someone is studying a particular organism that has a particular kind of bond,” said author Peter Yunker. “We also hope this might bring more biophysicists and evolutionary biologists together.”
In the early stages of multicellularity, the type of bond can have a big impact on the future of the organism. By considering each bond’s benefits and limitations, the group hopes to explore their effect on evolutionary trajectories. They are specifically investigating snowflake yeast, which demonstrates non-reformable bonds and changes from individuals to multicellular groups on short timescales.
Source: “Varied solutions to multicellularity: The biophysical and evolutionary consequences of diverse intercellular bonds,” by Thomas C. Day, Pedro Márquez-Zacarías, Pablo Bravo, Aawaz R. Pokhrel, Kathryn MacGillivray, William C. Ratcliff, and Peter J. Yunker, Biophysics Reviews (2022). The article can be accessed at https://doi.org/10.1063/5.0080845 .
