Month: September 2022

YEAST DIVISION OF LABOR. "We also observed the evolution of division of labor within the cluster: most cells remain viable and reproduce, but a minority of cells become apoptotic. Apoptotic cells act as break points within multicellular clusters, allowing snowflake yeast to produce a greater number of propagules from a given number of cells. This is functionally analogous to germ-soma differentiation, where cells specialize into reproductive and nonreproductive tasks. These results demonstrate that multicellular traits readily evolve as a consequence of among-cluster selection." https://lnkd.in/d3qm3Gr View in LinkedIn

YEAST CO-OPTED FUNCTION. "Apoptosis rapidly evolved a new, co-opted function in our multicellular yeast with no obvious parallel in the unicellular ancestor. Similarly, the existence of apoptosis-like cellular suicide in the unicellular ancestors of metazoans may be an important preadaptation, facilitating the evolution of complex multicellularity." http://www.pnas.org/content/109/5/1595.full View in LinkedIn

POPULATION SURVIVAL. Disposable soma theory. "That populations survive indefinitely while individuals grow old and die requires that young offspring be produced at the expense of old parents, and this has classically been explained in terms of an immortal germ line passing through a transient and disposable soma, or body." https://lnkd.in/d9ymnPc View in LinkedIn

"THE DISPOSABLE SOMA THEORY on the evolution of ageing states that longevity requires investments in somatic maintenance that reduce the resources available for reproduction. Experiments in Drosophila melanogaster indicate that trade-offs of this kind exist in non-human species. The findings show that human life histories involve a trade-off between longevity and reproduction." https://lnkd.in/dusZvgm View in LinkedIn

TWO AGING THEORIES. "Evolutionary theories of aging predict the existence of certain genes that provide selective advantage early in life with adverse effect on lifespan later in life (antagonistic pleiotropy theory) or longevity insurance genes (disposable soma theory).” http://www.tandfonline.com/doi/abs/10.4161/cc.28433 View in LinkedIn

IMMORTAL CELL? "Every single-celled organism alive today has been in existence since life began over 3 billion years ago. This is because individual cells do not give birth, they divide. After cell division, the two cells that result are each as old as the single cell that preceded them. The cell does not become younger by dividing. (Although this may not be exactly true). Thus every cell in your body is over 3 billion years old." https://lnkd.in/d4CsfeX View in LinkedIn

CLEAN SLATE VS MAINTENANCE. "The strategy that multicellular organisms such as humans use to project themselves into the future is to create new cell colonies from a single undifferentiated cell rather than maintaining existing colonies indefinitely. The main reason is that reproduction is more flexible and robust than maintenance, and it provides a way of starting over with a "clean slate" and slightly different genes." https://www.quora.com/Death-and-Dying-According-to-the-theory-of-evolution-why-do-we-die View in LinkedIn

REBOOTING THE SYSTEM. "Complex organisms accumulate billions of errors and problems over their lifetime. Most of these errors are fixed as fast as they happen, but life takes a toll and not all problems are reversible. Just as reinstalling Microsoft Windows every so often fixes accumulated system issues, so does generating a new organism every so often from a single cell." https://www.quora.com/Death-and-Dying-According-to-the-theory-of-evolution-why-do-we-die View in LinkedIn

FOOTNOTE. "There is evidence that even in "symmetric" cell division, one child cell may be slightly "younger" (less prone to death) than the other. Aging and death in an organism that reproduces by morphologically symmetric division." https://www.quora.com/Death-and-Dying-According-to-the-theory-of-evolution-why-do-we-die View in LinkedIn

ASYMMETRIC DIVISION. "With the discovery of aging in single-celled organisms with no clear separation of these two constituents, it has been proposed that reproduction by asymmetric division is a prerequisite for aging and that organisms that reproduce without a distinction between parent and offspring do not age, thus exhibiting functional immortality." http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.0030045 View in LinkedIn