Yeast proves physics can create multicellular life without mutations.

• Nishant Narayanasamy and Shashi Thutupalli’s lab at the National Centre for Biological Sciences (NCBS) in Bengaluru, India, has discovered a unique phenomenon: snowflake yeast.
• Snowflake yeast, which grows as a single cell, has a unique ability to grow larger than regular yeast.
• The yeast’s genetic composition prevents the bud from falling off, allowing it to cluster into a snowflake shape.
• The snowflake yeast’s growth is a mystery, as it lacks a biological structure, which would cause some cells to lack sufficient nutrients.
• The researchers from Georgia Tech reported a mechanism by which the yeast can ensure all its cells receive nutrients, even when the cluster is large.
• The study suggests that physical and chemical phenomena could have helped unicellular organisms evolve into multicellular ones before genetic changes.
• The researchers hypothesized that a different process, advection, could have helped unicellular organisms evolve into multicellular ones before genetic changes.
• The researchers observed that when snowflake yeast clusters grow, they consume glucose from the solution, reducing the density of the solution in places where it surrounds the yeast.
• The researchers concluded that the flow that kept the yeast cluster alive and growing resulted from the same principle: as the cluster consumed the sugar and produced alcohol and carbon dioxide, the solution’s density dropped, and this fraction spontaneously moved upward, generating the flow that kept the yeast cluster alive and growing.
• The study supports the idea that multicellularity could originate and be maintained initially solely on the basis of physics and chemistry, with no genetic change.
• The next step is to check if such a change subsequently occurs in the yeast, rendering multicellularity a part of its biological blueprint.