Researchers studied the sleep patterns of fruit flies with a mutation in the "SRKO" gene and compared them to normal flies (wt). They found that the SRKO flies had a higher arousal rate in response to light stimuli, indicating a greater intensity of sleep. Additionally, the SRKO flies took longer to fall asleep compared to the wt flies. These findings suggest that the SRKO gene plays a role in regulating nighttime sleep and the response to stimuli.