A team of scientists, including CIFAR’s Marla Sokolowski from the University of Toronto, has determined that there are disadvantages to being resilient to sleep loss. In humans, genetic variation allows some to have this resiliency.
But despite the advantages of having this ability, why don’t all humans have this genetic variation? Dr. Sokolowski and colleagues from the Washington University School of Medicine used fruit flies to try to explore this question. Fruit flies have two naturally differing versions of a particular gene called the foraging gene. Flies with the ‘rover’ version of the gene are more active and cope well with sleep deprivation compared to flies with the ‘sitter’ version. The team tested how these two different types of flies would react to lack of sleep and food. They discovered that although the rovers coped well with sleep loss, their short-term memory was impaired when they were starved during sleep loss. Meanwhile, sitters had improved memory when starved during sleep loss, and they lived longer when starved as well. Their findings suggest that being resilient to sleep loss is connected to vulnerabilities in other aspects of life. It also explains why rovers have not wiped out sitters in the evolutionary trajectory of fruit fly populations.
Understanding this trade-off in fruit flies gives scientists better clues and a stronger grasp of the function of sleep in our evolution.