The biological world is dominated by multicellular plants and animals. All of these intricate forms have evolved from single celled ancestors. What could explain the transition from single cells to cooperative groups, to groups of cells that put the prosperity of the whole group before the one? This is the essential question of how organisms evolved from single celled types and it is one of life’s great mysteries.
In ground-breaking research reported in this week’s edition of the science journal Nature, researchers from New Zealand, Germany and the USA report the real time evolution of life forms that have all the hallmarks of multicellular organisms. Beginning with single cells, the researchers show how simple cooperating groups of bacteria can reproduce via a life cycle that incorporates ‘cheating’ cells as a primitive germ line.
Cheats are cells that do not contribute to the integrity of the group, but still take advantage of the benefits of being part of a collective. An over abundance of cheating cells can cause the group to collapse. Lead researcher Distinguished Professor Paul Rainey from the New Zealand Institute for Advanced Study (NZIAS) and Allan Wilson Centre at Massey University, and the Max Planck Institute for Evolutionary Biology in Germany, points out that the idea that cheats might be integrated into a life cycle is counter-intuitive.
"Cheats are typically viewed as the greatest impediment to the emergence of multicellular life because they collapse cooperating groups, the obvious thing to do is to get rid of them."