Wednesday, June 2, 2010
Sleep is a behaviour that is common in all animals but the reason to how lack of sleep can affect the animal’s condition requires further investigation. A study was done to look more closely at this behaviour from sleep and activity patterns of 40 different lines of 3,500 of wild Drosophila melanogaster (fruit flies) at the genetic level as it may contribute to the understanding of human sleep. Fruit flies normally sleep 12 hours a day. The researchers found out that the fruit flies were homozygous but the lines were different and each one of these flies were placed in a small glass tube which were connected to a machine that monitored the activity of the flies every minute using infrared sensors. The study found that in male flies, the duration of sleep was longer than female flies on average. Also, males slept more during the day and were more active when awake than females. Almost 1700 genes were identified in the study and some were not known to have an effect on the variability of sleep in fruit flies before this study was conducted. Some genes that were thought to have an effect on sleep duration were verified by separate mutations in those important genes and effects on sleep duration were observed. They also found mutants that survived on little to no sleep - one to two hours a day or none at all. The sleepless flies had a mutation of a particular gene and they have named Sleepless. “They believe the Sleepless gene encodes a protein that affects whether potassium ion channels in the brain stay open or closed. When the channels are open, the brain is connected and working – the fly is awake. When closed, the channel shuts down and the fly sleeps. The insomniac fruit flies had less of the Sleepless-produced protein.” Groups of genes that affect sleep were identified in the study and now there is a greater understanding of how genes relate to sleep.
Sleep is regulated by two processes known as circadian and homeostatic. Circadian regulation affects the timing of sleep, and the homeostatic mechanism affects the need for sleep. The Sleepless gene affects the homeostatic mechanism.
Sleep is not just for humans ,it has been observed in everything from flies to dogs to people, indicating that it's essential to life. Insufficient and poor-quality sleep is an increasing problem in industrialized nations. In the U.S. alone, about 70 million people suffer from chronic sleep problems, which reduce workplace productivity, affect quality of life and can even be lethal. Therefore, we should do further investigation to have a better understanding of how genes relate to sleep.
Tuesday, June 1, 2010
Researchers at the University of Pennsylvania School of Medicine have discovered that a kind of gene labelled "jumping genes" within a genome has extensive variations in different individuals, as found through gene mapping of these jumping gene locations. From this finding, the researchers have postulated that these jumping genes may be a driving factor in our genetic diversity. This is highlighted by the results of the study, which showed that out of the 1139 genome sites observed, approximately 285 sites would be different for any two individuals. The reason for these variations were found to be due to the jumping genes, which are essentially DNA sequences that may "jump" from one location in a cell's genome and "land" in another location within the same cell's genome.
While previously the significance of these genes influence on genetic diversity was underestimated, this study proves these genes result in large variation in genome sites and that jumping genes could thus be described as the raw force behind genetic evolution.
Also known as transposons, jumping genes can influence an organism in many ways, as even subtle changes in an organisms genome can result in distinctly different phenotypes. Every individual would have these jumping genes, which may jump and insert genetic material into new locations. This could thus result in negative effects on cell structure (like genetic diseases and cancer), creation of new genes, or decreasing the expression of genes near the jumping genes' landing site. All factors would increase the diversity of an organisms' genome.