Scientists have successfully mapped the genome of a spider. The honor of being the first spider to ever have its genome mapped belongs to the velvet spider.
An international team of researchers from the Aarhus University in Denmark and the Beijing Genomics Institute (BGI) in China completed the mapping and their findings came as a bit of a surprise. The scientists found that there were certain genetic similarities between humans and the eight legged arthropods. Unlike other arthropods whose genomes are very different compared to humans, spiders have longer introns and shorter exons similar to humans. Introns and exons are parts of a gene. Exons are the parts of genes responsible for coding proteins.
Spiders are the largest group in the arachnid class. All spiders have eight legs and they can be found in six continents. In fact, the only place where spiders have never been found is Antarctica. These organisms have successfully adapted to a wide range of habitats. However, scientists have been trying to gain a deeper understanding of these organisms and the newly mapped genome may be the key to unlocking many of the spider's secrets.
Similarities between humans and spiders aside, gaining access to the completely mapped genome of a spider can revolutionize the way scientists understand arachnids. Studying an organism's genome can help scientists uncover a wealth of information about how spiders evolved and how they function.
"In brief, we've acquired a tool for everyone interested in spiders," said Aarhus University researchers Kristian W. Sanggaard and Jesper S. Bechsgaard.
Along with BGI's Xiadong Fang, Sanggard and Bechsgaar completed the historic genome mapping project. The researchers published their findings in the online journal Nature Communications. Most spiders in the world can be classified into two groups. The scientists working on the mapping projects studied spiders from two of the three major groups including a velvet spider and a tarantula, one of the large members of the spider family. While the genome of the velvet spider was successfully mapped, the researchers are still trying to complete mapping the genome of the tarantula. The researchers found certain gaps in certain sections of the tarantula genome and the scientists will need to resolve the gaps before the tarantula genome is completed.
"The idea was that, by comparing their genetic makeup, we'd try to see whether we could say anything in general terms about what makes a spider a spider," said Sanggaard. "But we found a number of genes - about two to three hundred - that have only been found in these two types of spiders and not in other organisms. They could be candidates for genes specific to spiders," Bechsgaard added.
The researchers had difficulty finding certain similarities between the two groups of spiders. This did not surprise the scientists since over 300 million years have passed since both groups of spiders evolved from a single common ancestor.
After the velvet spider genome was mapped, the researchers went even further by analyzing the composition of the proteins produced by both spiders when they produce silk or secrete venom. The protein analysis further added to what is currently known about spiders. Spider venom can be very dangerous for humans and further understanding of the venom could lead to more effective treatments for spider bites. Spiders are very efficient hunters and are able to kill and/or disable their prey with a single bite. Aside from producing more effective treatments for spider bites, the new research may also unlock novel uses for spider silk in medicine and other fields of study.
On the other hand, spider silk has long held the interest of both scientists and engineers due to its strength. The new study may help unlock some of the secrets behind the strength of spider silk. The analysis conducted by the researchers could also lead to possible industrial applications for spider silk and the development of stronger synthetic materials that could emulate the properties of natural spider silk.
"People can select an aspect or feature of the spider they're interested in, and then utilize the ‘genetic map' we published and which we ourselves have used to study silk and venom. This provides completely new opportunities for spider researchers," say the two Aarhus researchers.