‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ TheDepartment of Ecology and Evolution recently presented a series of lectures by StephenPalumbi, Ph.D., a professor at Stanford University and a nationally renownedevolutionary biologist. The talks focused on the role of human society in evolutionaryprocesses.
His most recentlecture was titled, ‘?Friends, Foes and Food: Human Impact onEvolution.’ He discussed how societal norms promote the evolution of ourown species by imparting the valuation of certain physical and mentalcharacteristics over others.
Another exampleof the human impact on evolution is the evolution of domestic food products likesalmon. Since consumers have shown a tendency to favor larger, more grownfish, the salmon industry has adjusted its produce accordingly. The industrynow favors the accumulation of larger fish to such an extent that geneticengineering is being used to enhance the expression of growth hormone genes.As a consequence of such bias, smaller salmon have increased in wild salmonpopulation. Human will, Palumbi said, profoundly influences evolutionaryprocesses.
Perhaps the mostobvious evolutionary impact humans have had is exhibited through bacterial andviral resistance. Since the discovery of penicillin, humans have been in aconstant arms race with harmful bacteria. During the 1940s and 50s, the affectof penicillin was remarkable. But beginning in the early 60s, its effectdecreased significantly due to the evolution of bacterial resistance.
Ultimately, newantibiotics were made to counter bacterial evolution. But this cycle hascontinued over the years, as the discovery of each new antibiotic has eventuallybeen met with bacterial resistance.
Human influence onviral and bacterial evolution has led to one of the most problematic issuefacing scientists today, the treatment of HIV. ‘?We are treating not justthe disease, but the evolution of the disease,’ Palumbi said.
HIV is aretrovirus, and converts RNA into DNA. However, the enzymes it uses for theseprocesses are highly inefficient, and often produce mutations. Research hasshown that HIV can exhibit the ability to adapt to individual genotypes byrecognizing individually specific immuno-alleles.
Despite the complexityof HIV, Palumbi said, there are efficient ways to treat it.
‘?Evolutionis just not a theory, but it is something we can expect,’ he said. ‘?Andgiven that we have very powerful medicine, we should expect evolution.’
Methods of HIVtreatment have been developed with such a perspective. For example,’?treatment overkill’ uses a triple-drug therapy regimen. Differentdrugs are used for the purpose of attacking different parts of the HIV virus,thus slowing the progression of resistant evolution.
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Palumbi stressedthat societal change and evolution are not two independent processes, but thatthe course one takes determines the course of the other.
