How, precisely, might we go about detecting evolutionary changes in the frequencies of genes in populations over time?
At Inexpressible Island (so named because the early explorers could not think of a word bad enough to describe it), our research team took blood samples from a large number of penguins in the colony there. With the help of our collaborator, Professor Carlo Baroni from the University of Piza, we also collected sub-fossil penguin bones and radiocarbon dated some of these to determine their age – estimated to be around 6000 years old. Next, we isolated nine sets of nuclear DNA sequences from both the modern and the ancient samples and examined the sequences for changes in the frequencies of different gene variants (‘alleles’). In fact, we did record some changes in the frequencies of alleles over time. This was the first demonstration of evolution in the sense of gene frequency shifts over a 6000 year period. Other studies have shown changes over much shorter time periods. As part of our study we also wanted to measure the speed or rate of evolution; that is, how fast changes in the genet
