Thursday, June 12, 2014

Nigel Goldenfeld: We Need a Theory of Life

Nigel Goldenfeld: The prejudice that one runs into often (but not always) when one talks about evolution is that evolution really is dominated by what's called vertical gene transfer, where first of all evolution is essentially all about genes -- operations and effects -- evolution occurs because mutations in genes are transmitted to offspring and there's a standard natural selection approach.
There isn't any doubt about this role of population dynamics in biology, by which I mean that entities can replicate and perhaps dominate a population. But the ways in which genetic novelty can emerge and be transmitted are much broader than that, and provide additional channels through which the well-understood mechanisms of population biology can act.
For example, Lamarckian evolution is definitely something that happens in the biological world. As a matter of fact, Darwin himself did not exclude that possibility in Origins of Species. But most people, most lay people and most biologists would regard the idea of something Lamarckian happening as something not within the standard picture of evolution. Lamarckian in this sense really means the inheritance of acquired characteristics.
Suzan Mazur: Epigenetics.  

Nigel Goldenfeld: Yes. But there is an even simpler, less controversial example -- horizontal gene transfer.
If you are a bacterium and you receive a plasmid and some genes and you can then later express those genes and transmit them to the daughter cells, that's an absolutely manifest example of something that was acquired in the lifetime of an organism, the result of its environmental interactions that gets transmitted to its offspring. We know that horizontal gene transfer is a significant force in microbial evolution. 
Suzan Mazur: So it's happening inside of us, and outside of us as well, horizontal gene transfer because of our microbiota. 

Nigel Goldenfeld: Yes. Exactly. That's exactly right. It's responsible in part for the proliferation of antibiotic resistance genes. Antibiotics are becoming less effective as a result of horizontal gene transfer.