There are more than 18,000 documented **species of butterflies** worldwide. They are one of [the most diverse groups](https://noticiasambientales.com/animales/ee-uu-las-mariposas-disminuyeron-un-22-en-los-ultimos-20-anos/) within the animal kingdom. The **colors on the wings** of butterflies fascinate scientists and naturalists alike.
An international team of researchers discovered that the **regulation of black color** on butterfly wings does not depend on the cortex gene, as previously thought, but on a **microRNA**, a molecule known as “mir-193”.
A discovery that challenges previous hypotheses
This finding challenges previous hypotheses and raises new questions about the genetic control of **pigmentation in lepidopterans**. The results were published in the journal Science.
The study was conducted by scientists from Singapore, Japan, and the United States, led by Professor Antonia Monteiro and Dr. Shen Tian from the Department of Biological Sciences at the National University of Singapore.
The identification of **mir-193 as a regulator of pigmentation** suggests that microRNAs play a crucial role in the evolution of color patterns in animals. This could change the way genes are investigated for their influence on the physical characteristics of living beings.
An enigma about butterfly color
Although it has long been known which **ecological factors** influence whether butterflies have **melanin on their wings** or not, it was still not well understood which genes and molecular processes control these changes.
For decades, scientists assumed that the **cortex gene** was the “switch” that controlled melanin coloration. This assumption was based on the fact that variations in pigmentation were usually linked to the **DNA region** where the gene is located. However, contradictory evidence began to cast doubt on its role.
This uncertainty led researchers to explore other genomic features within the same DNA region.
How scientists investigated pigmentation
To determine which element within the genomic region was responsible for the black color on the wings, the team used the **CRISPR-Cas9 genetic editing tool** to inactivate different genes in model butterflies.
They worked with three species belonging to deeply divergent evolutionary lineages: the **African brown butterfly**, the **Indian white butterfly**, and the **common mormon**, a species from Asia.
The researchers used CRISPR-Cas9 to inactivate the mir-193 microRNA in the three butterfly species. The goal was to verify if this was the regulator of black color on the wings and if its function remained in different **butterfly families**.
This microRNA is a small non-coding RNA molecule that regulates the expression of genes involved in **melanin production**. It is conserved in different animal groups, indicating that its function has been maintained throughout evolution.
The effects of modifying mir-193 in different species
In the African brown butterfly (Bicyclus anynana), the elimination of the molecule reduced the amount of melanin on the wings, antennae, legs, and abdomen. This caused a **shift to a light brown tone** on the wings and the loss of black color in the eye patterns.
In mutants with larger deletions, individuals were unable to fly, suggesting that mir-193 also influences other body structures.
In the Indian white butterfly (Pieris canidia), the change led to the removal of all black and gray pigmentation. **The wings became completely white**, without affecting the yellow areas. This demonstrated that mir-193 exclusively regulates melanin without influencing other pigments present in the species.
In the common mormon (Papilio polytes), genetic editing also eliminated the black color from the wings, but in this case, **new patterns in white, yellow, and red colors** were expressed. This suggests that, in this species, mir-193 not only regulates melanin but also could influence the expression of other pigments or allow other pigment genes to take a more prominent role.
In all species, according to the researchers, **mir-193 proved to be the main regulator of black color** on the wings.
However, there were differences in the observed effects: in Bicyclus anynana, the mutation affected beyond the wings and altered the ability to fly; in Pieris canidia, the change was limited to converting black to white without altering other colors; and in Papilio polytes, the loss of black allowed the expression of other colors, indicating a more complex regulation of pigmentation.
The importance of butterflies in nature
Butterflies are [very important pollinating beings](https://noticiasambientales.com/animales/la-produccion-de-cultivos-se-resiente-por-la-falta-de-insectos-polinizadores/) in various agricultural crops. Additionally, their ecological function is also a food source for predators such as **birds, spiders, lizards, and other animals**.
The importance of butterflies also includes the fact that they are excellent not only for nature but even for your garden, as they are attracted to bright flowers and **need to feed on nectar**. When they do this, their bodies collect pollen and transport it to other plants. This helps **fruits, vegetables, and flowers produce new seeds**. Most plants need pollinators like bees and butterflies to reproduce.
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