Scientists have modified the genetic makeup of the daddy long legs arachnid's daddy long-legs arachnid using RNA interference (RNAi). This allowed the distinctive spindly limbs to become twice as long.
This process uses the gene's DNA sequence and small fragments RNA to turn off the gene. It was used to treat the Phalangium species, which is one of the most popular species of daddy long-legs worldwide.
This results in a daddy with short legs instead of long legs. The research team hopes that the experiments will reveal more about the evolution of these long limbs.
The researchers wrote in a published paper that they expect the genome of P.opilio to facilitate the development more sophisticated tools for functional genomics. This will allow them to better understand how long-legs are made by daddy long-legs.
Researchers have identified three genes that serve as a map to different body parts after sequencing the genome of P.opilio. The legs of two of these genes were found to be activated in the embryos of arachnids.
The silencing or turning off genes in other embryos resulted in daddy long-legs. Two or more of their legs were shorter that normal, and they had transformed into pedipalps. These limbs are used for food handling.
The third gene that was linked to the development of legs in embryos was then shut down by the team. Although the legs did not become pedipalps they became shorter and less able to grip with their tarsomeres. Similar experiments were conducted on fruit flies.
"Looking ahead, we are interested to understand how genes give rise new features of arachnids such as scorpion pinchers and spider fangs, and also leverage the genome to create the first transgenic harvestmen," Guilherme Gainett from the University of Wisconsin, Madison, told CNET.
Technically, P. opilio is not a spider, but a close relative. This makes them useful in understanding how all the different arachnids that inhabit our planet evolved. Some daddy long-legs can wrap around twigs or other objects, but not all.
It is believed that the spider genome was duplicated in the distant future, which gives these creatures a large selection of genes to use on their unique evolutionary journeys. There could also be a link between more complex genomes or greater organism variation.
This research will be useful for future work to track back the evolution of P.opilio, and other arachnids. It also helps to determine if long and spindly leg traits were something that evolved in different arthropod groups.
In a published paper, the researchers write that P. opilio's effectiveness of both single and doubleRNAi makes it an ideal point of comparison in future studies of arachnid body plans evolution.
Proceedings of the Royal Society B: Biological Sciences published the research.