Tissue-Specific Stem Cell Mutation, Selection, and Evolution as a Cause of Aging

There is a mature literature on evolution and aging intended to explain how, despite selection for the morphological, metabolic, physiological, and behavioral prerequisites for survival and procreation, with the passage of time bodies deteriorate ultimately resulting in death. The focus of such explanations is typically on concepts such as age-related variation in the potency of selection and the related notion of antagonistic pleiotropy (Fabian and Flatt, 2011), by which suggests that genes able to promote survival and reproductive success in youth may increase loss of function with age. These concepts address selection on intact organisms. In contrast, a recent article in Science (Goodell and Rando, 2015) contains an article addressing the role of selection directly on somatic cells and in particular tissue-specific stem cells. (more…)

Toward an evolutionary model of cancer: Considering the mechanisms that govern the fate of somatic mutations

Andrii I. Rozhok and James DeGregori


PNAS July 21, 2015 vol. 112 no. 298914-8921

Abstract

Our understanding of cancer has greatly advanced since Nordling [Nordling CO (1953) Br J Cancer7(1):68–72] and Armitage and Doll [Armitage P, Doll R (1954) Br J Cancer 8(1):1–12] put forth the multistage model of carcinogenesis. (more…)

Do we expect the body to be a “One Hoss Shay”?

In an 1858 humorous poem The Deacon’s Masterpiece, or the Wondeful One Hoss Shay, Oliver Wendell Holmes Sr. described a carriage so artfully constructed as to have no weakest link. The carriage ran smoothly for exactly a hundred years, and then one day

it went to pieces all at once, –
All at once, and nothing first, –
Just as bubbles do when they burst,

leaving its driver sitting atop a pile of rubble and dust.

(more…)

Biology of Death

Death is one of the most mysterious and inexorable problems in biology. How does life end? What is the true nature of death? Is it absolute—a fundamental state? Or is it relative and a matter of degree? Can it be defined as part of some basic reality, a detail of an unknown whole rather than merely an illusion? Although any living creature anytime can lose its life, no creature can lose its death. This is why death is safe and secure in all living things. As bioethicist Ronald Dworkin (1993) noted, death, as it were, is part of life’s dominion. (more…)