1 Hoffman's team reported that on the East Coast of Australia, the classical latitudinal genetic clines of Drosophila have shifted over the past 20 years an equivalent of 4 degrees latitude (some 400 km), which means that genetic clines are now found in flies 400 kilometers away from where they were 20 years ago.
The researchers focused their analysis on the alcohol dehydrogenase (Adh) locus, since the Adh gene has been correlated with natural variation due to temperature, rainfall, and humidity changes. In addition to tracking the gene's presence in different populations, "we're basically trying to track down what the Adh does," says Hoffman. "It now is a marker for temperature change, and shifts as temperature shifts." The Adh gene does have an impact on phenotype; it has been linked, for instance, to body size. "We've been trying to track down precisely how selection acts on that ...
