The Evolution of Evolution
02/07/10 21:19 Filed in: GenomeWeb Daily Scan
Submitted by S. Pelech - Kinexus on Fri, 07/02/2010 - 21:19.
The Dan Jone's article in the New Scientist on the 'evolvability' points to an organism's mutational robustness to permit accumulation of positive, negative and neutral gene mutations, and it highlights a key role of heat shock proteins in underlying this robustness. A second key factor that was recognized was a phenomenon known as integration - the way different body parts or traits appear to vary and evolve together.
It seems to me that the main driving factor in evolution is the ability of an organism to successfully adapt to changing environments and pass these adaptive traits to their progeny. Depending on the organism, this requires development of at least one of three levels of intelligence - molecular, cellular or social. What is inherent in all of these intelligence systems is a high level of redundancy and feedback control. In the case of protein kinases signalling networks, which is an example of a molecular intelligence system, there are many different protein kinases that can target the very same phospho-site, and a given protein may feature several different phospho-sites that affect its activity. Protein phosphorylation appears to permit tens of millions of connections between the 23,000 proteins encoded by the human genome, which represents an incredible degree of integration. With respect to robustness, an amino acid change, even in an important regulatory phospho-site, can usually be tolerated. It is only when an accumulation of complementary mutations occur during the lifetime of an organism so that there is an strong gain of function and loss of negative feedback control does this actually lead to a lethal disease like cancer.
Link to the original blog post.
The Dan Jone's article in the New Scientist on the 'evolvability' points to an organism's mutational robustness to permit accumulation of positive, negative and neutral gene mutations, and it highlights a key role of heat shock proteins in underlying this robustness. A second key factor that was recognized was a phenomenon known as integration - the way different body parts or traits appear to vary and evolve together.
It seems to me that the main driving factor in evolution is the ability of an organism to successfully adapt to changing environments and pass these adaptive traits to their progeny. Depending on the organism, this requires development of at least one of three levels of intelligence - molecular, cellular or social. What is inherent in all of these intelligence systems is a high level of redundancy and feedback control. In the case of protein kinases signalling networks, which is an example of a molecular intelligence system, there are many different protein kinases that can target the very same phospho-site, and a given protein may feature several different phospho-sites that affect its activity. Protein phosphorylation appears to permit tens of millions of connections between the 23,000 proteins encoded by the human genome, which represents an incredible degree of integration. With respect to robustness, an amino acid change, even in an important regulatory phospho-site, can usually be tolerated. It is only when an accumulation of complementary mutations occur during the lifetime of an organism so that there is an strong gain of function and loss of negative feedback control does this actually lead to a lethal disease like cancer.
Link to the original blog post.