Can Cells Affect Genes?

Question

I recently saw a documentary that said that the theory of the "selfish gene" was under threat by evidence that cells can re-write (select for copying, or something) their own genes - but gave no further information. Does anyone have any information on this, or any other reputable challenges to the supposed sovereignty of the genotype? Thank you.

Answer 1

Cells can influence genetic expression by turning on stress response genes. These are switched by protein regulation in response to the environment. Diet and other stress can affect patterns of gene expression in the embryo and fetus as it develops. This determines many health prospects much later in life so cellular information does alter the genetic expression. There is no evidence this becomes germline encoded.

The one case of germline changes comes with sperm. In July 2006, Dr Corrado Spadafora, published evidence that sperm can take up DNA. Sperm have the means to block the intrusion of of foreign DNA that can fail. This has been done in the lab so is also possible in vivo.

http://lib.bioinfo.pl/auth:Spadafora,C

Sperm-mediated ‘reverse’ gene transfer: a role of reverse transcriptase in the generation of new genetic information

http://humrep.oxfordjournals.org/cgi/con...

Phenotype Plasticity in Genetic Programming

http://home.planet.nl/~gkorthof/kortho39...

Answer 2

I don't know of a mechanism which would allow for the directed alteration of the primary DNA sequence based on what's going on in the cell's environment.

However, I think that some kinds of heritable alterations to the DNA molecule which might be influenced by the environment, like methylation.

I think there might be some reason to think that bacteria, when they know they are in trouble, relax their error checking mechanism, which increases the odds that one of their mutated offspring will have a genetic edge in the crisis.

But other than that, I'm not familiar with what the documentary might have been talkning about

Answer 3

Try this-

Growing nerve cells in 3-D dramatically affects gene expression.

Cells grown in traditional 2-D culture, at left, are flattened with shorter neurite projections. Cells grown in 3-D, right, look more like cells in the body -- rounder with longer.



PROVIDENCE, R.I. [Brown University] — When it comes to growing cells in a lab, technique matters. A new Brown University study shows that nerve cells grown in three-dimensional cultures use 1,766 genes differently compared to nerve cells grown in standard two-dimensional petri dishes.

The study, published in the May issue of Tissue Engineering, adds to a growing body of research showing that culture techniques can significantly affect cell growth and function. This research shows that cells grown in a laboratory in 3-D environments, not in flat petri dishes, are more like cells grown in the ultimate 3-D environment – the human body.