Thursday, June 7, 2012

Collaborative Genes

By Kristopher Hite

The trait I admire most in a fellow thinker is the ability to entertain an idea without necessarily swallowing it whole. With that in mind, I eagerly listened to E.O. Wilson's On the Shoulders of Giants address at the World Science Festival in New York City last week.

I recently wrote about Wilson and his controversial rethink of altruism. Long story short, Wilson has created a ruckus by abandoning his long-held belief that cooperative and altruistic behavior among organisms can be simply explained as a veiled selfishness. When an organism appears to behave altruistically by sacrificing themselves or putting themselves in danger it is actually just the individual genes jockeying to survive by keeping identical copies of themselves alive in their relatives. This theory is known as inclusive fitness.

 In place of inclusive fitness E.O. Wilson now seems to embrace the controversial concept of “group selection.” This is the idea that genes for altruism persist by benefiting the entire group. The altruistic trait persists by helping groups themselves multiply; grow into larger and larger networks with more and more biomass. In group selection theory this all happens despite the fact that the altruistic trait is detrimental to the individual. Altruistic genes that band together and cooperate out compete groups of genes that act selfishly.

To me, both models seem like they could apply to different genes.

After the address, I had the rare opportunity to ask Wilson directly about his recent change of heart. I asked,
"If the gene is the basic unit of selection—the physical thing that makes it though the sieve of natural selection—then why do we need a 'group selection' model? And if a gene is not the basic unit of selection, then what is?" 

The question struck a chord. Wilson replied that he had been anticipating it, in fact, and quickly acknowledged that that his recent move away from the theory of inclusive fitness had rankled many people, including the famed evolutionary biologist Richard Dawkins who has popularized the selfish-gene view of evolution and has been a vocal critic of group selection. But Wilson stuck to his guns, saying,

"Yes, the gene is the basic unit of selection, but the phenotype is the target. It is as simple as that." 

Wilson flashed a smile, and for a moment I was starstruck, caught up in the glow of Wilson's legendary charm. The spell broke when I began to really chew on his answer. I was still extremely confused about how the concept of "phenotype as target" was supposed to justify group-selection theory. As I rode the elevator downstairs, I felt a pang of guilt for not pressing harder. I imagined a tiny Richard Dawkins sitting on my shoulder, eyebrows in a scowl, chiding me, "Kristopher, don't you remember how beautifully I explained all this to you in my book, The Selfish Gene?? How could you turn on me? Hamilton had it right, the gene is the one ring to rule them all everything else is myth!"

On the other shoulder (the "giant shoulder," one might say), I pictured a miniature E.O. Wilson, still charming in his diminutive tweed blazer, reassuring me, "Kristopher, everything is going to be alright as long as we work together in this big happy peer-reviewing group of ours."

I was, and still am, torn. As I stepped out of the elevator, I serendipitously met Nobel Laureate Harold Varmus, former head of the NIH, and I took the opportunity to ask him what he thought E.O. Wilson meant when he said "phenotype is the target of selection." Dr. Varmus clarified—somewhat. Phenotype, he explained, is the vehicle genes ride inside the physical manifestation of the genes. Selective environmental pressure, like changing atmospheric oxygen levels, or changing local climates are not capable of acting directly on any single isolated gene.

After I directed Dr. Varmus and his wife to the Christopher Street subway station, I continued to replay his answer in my head. If natural selection happens at the level of the physical manifestation of the genes – the phenotype, and there is no organism in existence with only one gene inside, then all genes must be collaborative in a sense.

And this is where I am in my thought process. If you have any corrections or criticisms I welcome them. They will only add to my understanding.
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