UPR scientists help discover how butterflies acquire their wing patterns

How do butterflies acquire their wing patterns? An international investigation, in which scientists from the University of Puerto Rico (UPR) Rio Piedras Campus participated, found the answer in a little-studied RNA molecule that regulates melanin in the early stages of development of these insects.

“The big finding is that we understand that an important molecule that controls where black and non-black pigmentation is on a butterfly’s wings is a non-coding RNA, which is a molecule that we don’t know much about yet.”explained the evolutionary biologist Richard the Popewho, together with Elizabeth Evans –a member of his Laboratory in the first teaching center in the country–, joined scientists from institutions in the United States and England to answer the question of how butterflies develop their morphological traits.

Dogma in biology often says that ribonucleic acid (RNA) takes genetic information from deoxyribonucleic acid (DNA) and creates proteins to regulate genes. But this discovery appears to represent a shortcut, Papa said, since non-coding RNA — which dictates the colors of butterflies’ wings — is not converted into protein but instead regulates morphology itself.

For years, the purpose of this RNA molecule, which is present in all living organisms, was unknown, although only a decade ago hypotheses began to be developed that it might have the capacity to regulate the development of genetic traits. This study is the most recent of a few investigations that demonstrate its effect.

To test the regulatory function of this molecule, scientists at universities in the United States, England and Puerto Rico They used a technique called CRISPR, which allows genetic modifications in living organisms.

Papa explained that this technique uses chemicals that are injected into the embryo to eliminate from the genome something that is not wanted to be present during its development, which helps to understand how certain molecules function.

In this experiment, after identifying non-coding RNA in the species they worked with, they cut off the function of this molecule and the result was a butterfly without melanin in its wings.

“We cut this region in the DNA so that non-coding RNA could no longer be produced, because it was not present in the gene. By not having that, we obtained a butterfly without pigment.”said.

The contribution of Papa and Evans – who completed her master’s degree a little over a year ago and currently works as a technician in the laboratory – to the study was to test the function of non-coding RNA in butterflies present in Puerto Rico.

“Our role was to test this molecule on local butterflies from Puerto Rico, which are the charithoniawhich they call the zebra butterfly, because it has stripes like a zebra, and the monarch butterfly, which is also a type of butterfly that we have here.”the biologist said.

These experiments, which lasted between two and three years, were developed in the Julio García Díaz Biology building, at the UPR campus in Río Piedras. Meanwhile, others were carried out at George Washington University, in the US capital; Cornell University, in New York; and the Universities of Cambridge and Bristol, in England. In each one, they tested with butterflies from their environment or those bred in laboratories.

Although scientists – led by Luca Livraghifrom George Washington University– were able to prove the regulatory function of non-coding RNA, but there is still much to study and understand about this molecule and how it carries the genetic message.

“When we think about development, one molecule may be the main actor, but it has to transfer this information to other genes. It is a series of interactions between genes, it is not just the molecule. What are those other actors that are being regulated by this non-coding RNA? That is the next question that has to be answered.”stressed Papa, who welcomed the publication of the research, at the beginning of September, in the magazine Proceedings of the National Academy of Sciences.

The Italian biologist, who has been a member of the UPR Río Piedras faculty since 2010, highlighted the importance of these opportunities for participation in research for students of the public university.

“It is an extra value that is brought to the students, the opportunity for them to interact with the international community, which creates a more stimulating environment… these are opportunities for the new generations”Pope stressed.

He also said that the extraordinary work done by UPR professors and students can often take a backseat amidst the negative news surrounding the university.

“This university has many good things, there are many amazing scientists and professors, who sometimes remain in the dark because of bad news. This is just one example, and there are many other good professors, of how the UPR provides the opportunity for scientists to make important international discoveries.”he said, highlighting the educational quality of the institution.