Goodbye Mr. Darwin and the selfish gene?
Jaroslav Flegr, a self-described “sloppy dresser,” the 53-year-old Czech scientist has the contemplative air of someone habitually lost in thought, and his still-youthful, square-jawed face is framed by frizzy red hair that encircles his head like a ring of fire. He is trying to change the way we think about Darwinian Evolution.
He suspected that Toxoplasma Gondii, an obligate, intracellular, parasitic protozoan that causes the disease toxoplasmosis, and with which he is infected is changing his behavior subtly so that his ‘selfish’ genes are more or less now slave to those of the genes of the parasite. If what he thinks is true, Jaroslav is under more the selective pressure of the parasite than his own genes.
For fact, parasites inducing behavioral changes in hosts have been reported by many scientists. Toxoplasmosis is one of the most prevalent infection among humans. If you have affinity for cats, you are likely infected.
Jaroslav has come up with the idea of frozen evolution, which suggests that new adaptations by accumulation of random mutations happen only when their members are genetically uniform, i.e., only after a portion of the population of the original species has split off, balanced on the edge of extinction for several generations, and then undergone rapid expansion. After a short period of time,polymorphism accumulates in the gene pool due to frequency-dependent selection; and thus, in each generation, new mutations occur in the presence of different alleles and therefore change their selection coefficients from generation to generation. The species ceases to behave in an evolutionarily plastic manner and exists in this state until such changes accumulate in the environment that the species becomes extinct.
When you are a host, it is unknown in which direction your evolutionary future lies – survival or extinction.
So is it goodbye to Mr. Darwin or his celebrity proponent Dr. Richard Dawkins?