Sensitive Dependence on Initial Conditions

[selfAdjoint]

This new paper in Nature Genetics:

http://www.nature.com/ng/journal/v37/n8/abs/ng1608.html

suggests that considerable variance in lifetimes of C. Elegans with controled, identical genomes, is caused by an essentially random variable; the first encounter with a certain chemical in its environment.

From the abstract.

When both genotype and environment are held constant, 'chance' variation in the lifespan of individuals in a population is still quite large. Using isogenic populations of the nematode Caenorhabditis elegans, we show that, on the first day of adult life, chance variation in the level of induction of a green fluorescent protein (GFP) reporter coupled to a promoter from the gene hsp-16.2 predicts as much as a fourfold variation in subsequent survival. The same reporter is also a predictor of ability to withstand a subsequent lethal thermal stress. The level of induction of GFP is not heritable, and GFP expression levels in other reporter constructs are not associated with differences in longevity. HSP-16.2 itself is probably not responsible for the observed differences in survival but instead probably reflects a hidden, heterogeneous, but now quantifiable, physiological state that dictates the ability of an organism to deal with the rigors of living.

MZ (identical) human twins have 60%-80% less variance in IQ betweeen pairs than random members of the population, but the remaining 20%-40% might not be due to family environment or peer group history, but to random chemical events.


( courtesy of Gene Expression: http://www.gnxp.com/)

 

[Ygggdrasil]

See https://www.physicsforums.com/threads/alleles-and-genes.967716/#post-6146366 for similar discussion of how randomness and other non-genetic, non-deterministic processes can play a role in inheritance and development.