Geometry, programmed death might have enabled evolution of multicellularity

Geometry, programmed death might have enabled evolution of multicellularity

Geometry and programmed cell death may have helped along the evolution of multicellular life, according to new research led by SFI Omidyar Fellow Eric Libby.

Writing in the journal PLOS Computational Biology, Libby and colleagues argue that genetically-programmed likely evolved along with multicellularity, laying the foundations for the reproduction of multicellular organisms.

The team took inspiration for their results from a recent experiment on . In that study, researchers repeatedly grew the yeast Saccharomyces cerevisiae in test tubes and selected whatever sank to the bottom for more growth. Because the that stuck together tended to sink, larger clusters survived this artificial selection.

So too did rudimentary reproduction: when one cluster got too big, it would simply break apart, forming two distinct organisms. But a more counterintuitive trait evolved as well—individual cells that were programmed to die sooner than their unicellular ancestors.

One reason, Libby says, is space. In the multicellular yeast creatures, each cell can split in two, forming new branches along which the organism grows. But if the grow too large, they'll start to compete with each other for nutrients and eventually crowd each other out. Unabated, that trend would limit the success of the new species. With cells born to die quickly, however, an organism can avoid that fate. Rather than suffocate itself, cells die, breaking one creature into two more manageably-sized ones.

Still, why death? Isn't there some other way for the yeast creatures to break apart?

Other mechanisms might be "just as beneficial, but since death is a natural part of most organisms, it is wise to co-opt it in such a way to benefit the living," Libby says. "We must view the group organism as a completely new environment, one in which traits like cell death might have different consequences" for the health of living things.

Explore further

Scientists solve major piece in the origin of biological complexity

More information: PLOS Computational Biology (September 18, 2014): … journal.pcbi.1003803
Journal information: PLoS Computational Biology

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Citation: Geometry, programmed death might have enabled evolution of multicellularity (2014, September 22) retrieved 19 August 2019 from
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Sep 22, 2014
Article excerpt: " considering the geometry of a primitive multicellular organism we can gain insight into the initial emergence of reproductive division of labor during an evolutionary transition in individuality."

Sex differences in cell types of yeasts are nutrient-dependent and controlled by RNA-mediated events linked to fixation of nutrient-dependent amino acid substitutions by the pheromone-controlled physiology of reproduction in species from microbes to man -- without the pseudoscientific nonsense of evolution of sex in heterosexual or homosexual animals.

From Fertilization to Adult Sexual Behavior http://www.hawaii...ion.html

"Parenthetically it is interesting to note even the yeast Saccharomyces cerevisiae has a gene-based equivalent of sexual orientation (i.e., a-factor and alpha-factor physiologies). These differences arise from different epigenetic modifications of an otherwise identical MAT locus..."

Sep 23, 2014
If anyone else failed to make sense of the above post, don't bother. Kohl is a nutjob troll who spams physorg with his pseudoscience nonsense.

Sep 23, 2014
Predicting the human epigenome from DNA motifs

In my model, RNA-directed DNA methylation predicts that nutrient-dependent amino acid substitutions arise and stabilize DNA in the organized genomes of species from microbes to man via the conserved molecular mechanisms of nutrient-dependent pheromone-controlled ecological adaptations.

It seems obvious that only those who think mutations, natural selection and the evolution of proteins predict cell type differentiation in all cells of all individuals of all species are among others who think I am a troll or that I am spamming physorg with pseudoscientific nonsense.

LIke other serious scientists, I am refuting the pseudocientific nonsense of their ridiculous theories by calling attention to experimental evidence of biologically-based cause and effect. Of course that upsets the pseudoscientists and their idiot minions. But why don't they provide evidence, not insults

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