Evolution always works, in all areas of nature. However, it is always fun for biologists to watch evolution “in real time.” Part of that time of observation is indicated by the local clock – the sleep -wake mode – of the Drosophila melanogaster fly. In fruit flies, a type of “gene clock,” first seen in southern Europe 300 to 3,000 years ago, is spreading to the north, for example, and into Scandinavia. Researchers are aware of this phenomenon but cannot fully explain it. Based on experimental studies, a group led by neurobiologist Prof. Ralf Stanewsky from the University of Münster (Germany) was the first to give an explanation for this phenomenon.
The lesson, now published in the journal Nature Communications, focusing on the gene clock called “timeless.”. With a second clock gene (“time”), which controls the circadian rhythm of the egg, lasting about 24 hours. This music is constantly connected to the environment by using outdoor zeitgebers such as light and heat. The researchers investigated why a special feature of the timeless clock gene, the ls-tim allele, became so widespread.
“Like humans, Drosophila emerged from sub -Saharan Africa and spread northward, as far as the Arctic Circle,” explains first author Angélique Lamaze. “There, the bees see long summer days at or near constant light, which is called a white night.” Constant light interferes with the function of the internal clock because it induces the constant degradation of the “timeless” clock protein through the molecular reaction chain. Therefore, the circadian rhythm is lost.
However, hot circles can overcome the effects of constant lighting. Experts have shown that flies with a modified ls-time allele combine their circadian rhythms with ambient temperature under light and hot conditions such as the Scandinavian summer sun. Another indicator is the degree of movement of the inches. With constant lighting and a daily temperature range between 16 and 25 degrees Celsius, bees with the ls-time allele are more active in the second half of the warm season. In fact, as long as it’s light and warm, there’s no such thing. Unlike ls -tim flights, the change in mode is not shown – not with car heat and constant heat.
The new gene increases reproductive success
“From an evolutionary biology point of view, change in nature can be well defined,” says Angélique Lamaze. “Summer is the time to give birth. Animals that are united in their nature and ready to mate at the same time of the day are better able to meet and reproduce. It’s important perhaps it will continue to propagate to the right and be able to explain its evolutionary role. “
The research team also reported that one copy of the ls-tim allele was sufficient to be able to set the “Scandinavian standards,” further supporting the proliferation of this allele. Like humans, for example, moths have two or more identical copies of each gene – one copy from each parent.
The new type produces a protein that separates slightly from the original type, which is stable under light, and therefore, disrupts the molecular reaction cascade that induces the degradation of the “timeless protein”. ” This, the team concluded, is a prerequisite for the heat cycle to restore the circadian rhythm of the seed pods under constant light.
Neurobiologists have used a combination of genetic and new genetic and immuno-histochemical experiments in their study. Among other things, they compared the flies with genetic make-up, researching their appearance on Scandinavian summer nights and how their clocks work on brain neurons. .
More information on the local clock of the fruit fly
Angélique Lamaze et al, An unnatural polymorphism that allows the arrangement of the circadian clock to be on “white nights”, Nature Communications (2022). DOI: 10.1038 / s41467-022-29293-6
Presented by the University of Münster
Directions: Fruit flies change behavior on ‘white nights’ (2022, March 31) Retrieved 1 April 2022 from https://phys.org/news/2022-03-fruit-flies-white- nights.html
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