Thursday, June 11, 2009

Pervasive Natural Selection in the Drosophila Genome?

There is new review paper openly attacking the neutral theory:

Sella G, Petrov DA, Przeworski M, Andolfatto P (2009) Pervasive Natural Selection in the Drosophila Genome? PLoS Genet 5(6): e1000495. doi:10.1371/journal.pgen.1000495  

The authors essentially concludes that the neutral theory is largely false in the Drosophila system.  The implication is obvious, if it is false in one life form, it must be false for all life forms.  There is and can only be one theory for all life forms.  After all, we only got one DNA code universal for all life forms.   The paper is fully consistent with MGD hypothesis.

Some interesting quotes:

Analyses of genetic variation within and between species reveal that much of the Drosophila genome is under purifying selection, and thus of functional importance, and that a large fraction of coding and noncoding differences between species are adaptive.  (in other words, no such thing as neutral mutations)

The emerging evidence has implications for a wide variety of fields, from conservation genetics to bioinformatics, and presents challenges to modelers and experimentalists alike.  (Well, challenges no more.  The MGD neutralizes all challenges)

Recent evidence, however, is calling these assumptions (of the Neutral theory) into question. While the studies have been conducted in a range of taxa, the strongest case comes from Drosophila, where multiple lines of inquiry challenge the basic tenets of the Neutral Theory.

These findings cast doubt on the validity of the Neutral Theory in Drosophila, and possibly in other species, raising new and challenging questions for experimentalists and theoreticians alike.

Although the recent findings in Drosophila herald a shift in our view of genome evolution, they do not yet suggest a coherent alternative picture.  (The MGD is the alternative)