Climate change is changing genes

Genetics of fruit flies shows initial adaptations to warming

Fruit fly Drosophila subobscura in front of chromosome Raymond Huey
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Global warming has already left its first traces in the genes of organisms: comparisons of the genetic fingerprint of certain fruit fly species worldwide show that a gene code that is more favorable for flies in warmer regions has spread ever more widely. In some cases, less than two decades were enough for this process, as the study published in "Science Express" reports.

Joan Balanyá from the University of Barcelona, ​​together with colleagues from the College of William and Mary in Virginia, studied an originally only in Europe native fruit fly species, Drosophila subobscura. More than 40 years ago, European geneticists analyzed the genes of this type of fly, finding that parts of their chromosomes were upside down. The nature of these inversions, as the researchers found out at the time, was correlated with the latitude from which the respective flies came. In the north, certain reversals were much more common than in the south, while others were more common in the south.

Chromosome reversals latitude-dependent

In the late 19870s, this type of fly, probably with cargo ships to the Pacific coast of Chile, was also introduced to the west coast of North America in the 1980s. Since then, they have spread widely and can be found from California to northern Vancouver Island in British Columbia. Since 1985, researchers have also periodically collected samples of these flies and tested them for their genetic composition, in addition to re-sampling in Europe and South America. At the same time, the researchers registered the climate changes at the respective sample locations.

When comparing the old and new samples, the researchers noted a significant increase in the genome versions typical of the southern regions. Overall, there was a northward shift of these types of genes: The inversions agreed almost exactly with those that had been collected just a few decades ago, a degree south. This effect occurred on all three continents studied. At the same time, the temperatures at the respective places had risen.

"If the inversions are temperature-sensitive, one would expect a corresponding increase in inversions of the southern type in all latitudes, " explains Huey. In his view, the gene reversals could cause the flies to cope better with warmer temperatures. display

Genetic change on three continents

"This is a clear signal on three different continents that there is a climate change and that it brings genetic changes, " said the researchers. "The genetic change is remarkably fast and even detectable in samples that are less than two decades apart."

Rapid changes of this kind are most likely and most likely to occur in organisms that have a short lifespan, such as fruit flies, which can produce several generations per year. "The good news is that these flies can adapt, at least to some extent, to warming, " explains Huey. OrganisBut organisms with longer intervals between new generations, such as humans or sequoia trees, can probably not adapt so quickly. We humans are really fortunate that we have the technology that helps us deal with the changes.

(University of Washington, 05.09.2006 - NPO)