The genome is 7 times (!) Our size

The idea that an insect’s genome is relatively small and less complex could go straight to the trash can.

The Siberian Clapper Grasshopper (Bryodemella tuberculata) It is one of the most striking locusts in Central Europe. And not just because of its great looks. Researchers have succeeded in mapping its genome. And it turns out that this locust has a strangely large genome. The largest of the entire insect kingdom.

More on the Siberian Locust
The Siberian Clapper grasshopper is a rare animal. In northwestern Europe, this species declined sharply, almost making it extinct. At the moment, you can only find it in a few populations on the banks of rivers in the Alps. These endangered habitats were created through thousands of years of constant change due to the natural dynamics of rivers. The grasshopper owes its name to the loud flapping sound it can make.

In a new study published in the journal Plus oneThe researchers examined the genomes of fifty different locust species. Then they measured the genomes using flow cytometry (a technique for counting and studying microscopic particles in a flowing fluid). One of the locusts the researchers examined was the Siberian locust.

largest genome
The results show that the Siberian locust has a remarkably large genome, consisting of a whopping 21.48 billion base pairs. Not only is its genome the largest of all insects, it is seven times larger than ours (which consists of about three billion base pairs). The grasshopper thus dethroned the previous record holder, the grasshopper Diracantha Onos.

incorrect
This discovery turns everything we thought we knew about insect genomes on its head. That’s because scientists assumed the insect’s genome would be relatively small and less complex. But this assumption turned out to be completely wrong. “We are now seeing that genome size does not necessarily correlate with the complexity of an organism,” said researcher Oliver Holiczek. The only question is: Why does a locust have such a record-breaking genome? “Species easily adapt to different environmental conditions,” explains Hawlitschek. “This may have enhanced genetic diversity and led to the exceptionally large genome.”

size taken
The size of genomes varies greatly among different groups of animals—sometimes even within groups. For example, most insect genomes are much smaller than those of the Siberian Clapper’s grasshopper. Take the fruit fly, for example. Its genome is no more than a sixth of the human genome. Scientists have long searched for the reason behind this remarkable discrepancy. But there is a long way to go. The genome size has been revealed in only 1,345 of the more than 1 million known insect species. But what we do know in the meantime is that grasshoppers and cockroaches, in general, have the largest genomes.

The study provides further insight into the variation in genome size in locusts. Although there is still a lot to discover. In follow-up research, Hawlitschek wants to learn more about the evolutionary mechanisms that determine genome size using detailed sequence-based genomic analyses. And not just to expand our knowledge about the size of the genome in insects. Because the results may also have consequences for ourselves. “I am convinced that studying these extremes will also provide us with many insights into the function of the human genome,” concludes Holiczek.