For a little more than six decades, researchers at Kyoto University in Japan have been studying the effects of external factors on the genome of the typical fruit fly — more specifically, if keeping generations of fruit flies in the dark — can change particular factors of their genetic makeup, along with controlled interbreeding between average fruit flies with their variable group. After roughly 60 years of testing, researchers finally have an answer: yes.
The basis for this study, which was recently published in the scientific journal G3 (which stands for Genes, Genomes, Genetics), was the idea of environmental adaptation — genetic change prompted by environmental factors.
"Environmental adaptation is one of the most fundamental features of organisms," the article reads. "Modern genome science has identified some genes associated with adaptive traits of organisms, and has provided insights into environmental adaptation and evolution."
The years-long Kyoto experiment began in 1954 under the direction of ecologist Syuiti Mori, who kickstarted the study by placing a drove of fruit flies in a contained area and "sealing" it with a dark, light-blocking cloth in an attempt to see what would happen to both the original group and their offspring. Described by the scientific journal Nature as "one of evolutionary biology's longest-running lab experiments," a change became apparent to the biologists who participated in the study: the flies in captivity grew slightly darker in color and developed longer sensory hairs, earning the nickname "dark-flies," but more or less remained seemingly unchanged to the average "laymen," i.e., scientists who had not participated in Mori's generations-old experiment.
In 2012, another Kyoto scientist — a geneticist named Naoyuki Fuse — decided to take the test one step further by breeding their "dark-flies" with normal flies, or "light-flies," and keeping the resulting progeny in a dark environment — a breeding that lasted for roughly 49 generations, during which the researchers kept track of each generation's changed genes — which numbered at a grand total of 84 — to see if there was any effect on their physical capabilities.
"We found here that Dark-fly dominated over the wild-type fly in a mixed population under dark conditions, and based on this domination we designed an experiment for genome reselection to identify adaptive genes of Dark-fly," the scientists explained.
In the end, their theory proved to be correct: the bred dark-flies inherited sensory capabilities that let them navigate easily unlit or light-deprived environments, due to what the researchers believe to be caused by augmented sensory faculties and more acute chemical-signaling (i.e., pheromones).
Fuse, who does not have a permanent position at Kyoto, is unsure of what will happen to the project; despite this, the results of the experiment showed progress in one arena of scientific thought — that if the genetically-altered fruit flies were mainstreamed back into the general population, it could be possible that their cultivated characteristics could become more prevalent in future generations over time.
Source: G3
Photo: John Tann | Flickr
