Gene cambiante, la expresión puede ser ventajosaContributed by: AdminStaff1 · Views: 1,134
Contributed by: AdminStaff1 · November 22, 2007 @ 12:14 PM MST · Views: 1,134
Expression Can Be Advantageous
One gene for pea pod color generates green pods while a variant of that gene gives rise to the yellow-pod phenotype, a feature that helped Gregor Mendel, the 19th century Austrian priest and scientist, first describe genetic inheritance. However, many modern-day geneticists are focused on the strange ability of some genes to be expressed spontaneously in either of two possible ways.
UCSD postdoctoral fellow Matthew R. Bennett, left, and bioengineering professor Jeff Hasty are studying the how cells can spontaneously switch from one phenotype to another.
While the phenomenon is yet to be discovered in the human genome, the new results suggest that researchers studying bacteria should carefully design their experiments to measure variability due to epigenetic multistability. Even in human cells, multistability may play a role in genes can alternate between “on” and “off” settings.
“Scientists studying bacteria have simply not had the tools to understand phenotypic variability,” said Ting Lu, lead author of the study who was a UCSD graduate student in the lab of bioengineering professor Jeff Hasty. (Lu is currently a postdoctoral fellow at Princeton University.) “We’ve arrived at a theoretical framework that allows experimenters to measure the ephemeral nature of epigenetics.”
Epigenetic multistability may be vital to cells that are outwardly different, but genetically identical. Only one of the two phenotypes might thrive in a given environmental condition; however, the less advantageous phenotype could come in handy if the environmental conditions unexpectedly changed. By having both phenotypes, the chances would be better that the best one will be present when needed.
UCSD postdoctoral fellow Matthew R.
Bennett, left, and bioengineering
professor Jeff Hasty are studying
the how cells can spontaneously switch
from one phenotype to another.
The PNAS paper also documented that the time it takes for a population of cells to reach a stable variance depends on the initial growth conditions and how easily those conditions support cell growth.
“Different results can emerge depending on how cells are grown,” said Jeff Hasty, a professor of bioengineering at UCSD and senior author of the paper. “Our results should allow all researchers studying bacteria to better understand the variability they routinely see from one experiment to the next.”
This work is supported by the National Institutes of Health. While a graduate student at UCSD, Lu was affiliated with the Center for Theoretical Biological Physics, a $10 million National Science Foundation-financed center designed to apply the mathematical tools of theoretical physics to biology.
Rex Graham, 858-822-3075
Kim McDonald, 858-534-7572
Courtesy: University of California, San Diego