http://www.the-scientist.com/yr2002/may/rayl_p20_020513.html

http://longevity-science.org/TheScientist.pdf

**Published opinion of Professor F. Eugene Yates on
"Reliability
Theory of Aging and Longevity" published by Leonid A. Gavrilov and
Natalia
S. Gavrilova in the Journal of Theoretical Biology, 2001,
213(4):
527-545.**

"What the Gavrilovs have shown in a very clean mathematical model is that the assumption you make about how many of these defects there are initially has a tremendous amount do with what a population mortality curve is going to look like," says gerontologist F. Eugene Yates, professor emeritus at the University of California, Los Angeles. "They have shown that the shape of the curves comes out of the key assumption about initial defects and redundancy—those two assumptions and the notion of random hits. The beauty of their model is that just by tuning these three simple elements, the theory can fit any of the mortality curves that we have, including those of machines, the Weibullian ones."

Gerontologist Yates views the Gavrilovs' theory in a bigger-picture perspective. "In my observations of theorizing, and in my experience doing theoretical biology, I have found theories that have a lot of range lack precision, and theories that are very mechanistic have precision but not range. The Gavrilovs' model has both range and precision to a degree that is astonishing," he says.

"They have gone beyond pinning it on any particular gene, and beyond pinning it on free radicals and those sorts of mechanisms, and they're taking a statistical view, saying if this is the overall design picture you're working with then you're going to get these mortality curves and the theory works with transistors, drosophilae, and humans," Yates continues. "And they allow the possibility that whatever the defects—even if they were all cleaned out before you reach maturity, the model would still hold. I went through the arithmetic and it really does, which is all the more remarkable. Still, the theory requires, above all, the idea of redundancy and they still require polymorphisms and heterogeneity and random hits as their statistical mechanism for generating these beautiful population dynamics."

F. Eugene Yates, M.D.

Professor of Medicine Emeritus,

UCLA School of Medicine

1950 Sawtelle Blvd. #330

Los Angeles, Ca. 90025-7014

Phone: 310-312-0553

Fax: 310 312-0551

E-mail: FEYates@ aol.com

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