The rising lizard shows off its superhero genes

The lizard Podarcis muralis nigriventris it may not grow to incredible size and smash everything in its sight, but evolution has turned this lizard into something of an Incredible Hulk—green skin included. P. nigriventris is sort of like the imposing Marvel superhero compared to other types of common wall lizards (Podarcis muralis). While the regular version is usually relatively small and brownish to greenish-brown, nigriventris a subspecies found in central Italy is visually striking due to its green skin with black spots, larger size and increased aggression.

A team of evolutionary biologists led by Natalie Feiner of Lund University in Sweden set out to find out which genes contributed to the creation P. nigriventris so huge Like many fictional people with superpowers (but unlike the mutant Hulk), this lizard is a hybrid.

Huge hybrids

Although common wall lizards are found from the Iberian Peninsula all the way to Asia Minor, the researchers focused on lizards from populations in central Italy (IT lineage) and the southern Alps (SA lineage). These lineages most likely diverged from a common ancestor 5-6 million years ago and then began to hybridize—individuals from the different lineages mating with each other to create hybrid offspring.

P. nigriventris arises as a subspecies of the IT line. However, some of its characteristics have been passed down from SA ancestry. This is called introgression, which occurs when genetic information is transferred from one lineage or species to another as a result of hybridization. The characteristics the researchers focused on were back and belly coloration, lateral blue spots, body mass and head length.

because P. nigriventris traits have made their way into the SA lineage through introgression, it can be difficult to tell which is truly hereditary. It was first assumed that females selected for P nigriventris characteristics in men, which increases their chances of finding a partner. However, some of these characteristics were later seen in females, so these traits are not exclusive to males competing for females.

“Various lines of evidence support the existence of [these traits] in both sexes, and [the traits] remain intact during introgression into a distant lineage,” the researchers said in a study recently published in Science Advances.

The brown one P. muralis are considered the ancestral phenotype. To see how nigriventris If a phenotype occurs, Feiner will need to find where in the lizard’s genome the traits that make up that phenotype are located.

Green genes

What Feiner and her team discovered while analyzing the lizards’ genomes was that the characteristics that make P. nigriventris are determined by genes that regulate neural crest cells. These multipotent stem cells, which form during an early embryonic phase, can transform into different types of more specialized cells throughout the embryo, contributing to everything from heart valves to coloration.

One such gene, Rbm10, regulates the proliferation of neural crest cells, meaning their growth and division, while another, Tfcp2l1, regulates how they differentiate into more specialized cells as the embryo develops. Another, Gpc3, is required for neural crest cells to migrate to various locations in the embryo where they integrate into tissues.

But where was the difference that would ultimately change the color of nigriventris phenotype? The answer was in a region of a chromosome that contains a gene known as Rab18, which also helps in the migration of neural crest cells. Rab18 and Acbd5 both have a role in the production of pigments. This may be related to the green and black coloring of P. nigriventris.

“Gene flow analyzes revealed that this [chromosomal] a region possibly introgressed from the IT lineage into highly expressing SA lineage populations nigriventris phenotype,” the researchers said in the same study.

While the exact factors that caused these green and black P. nigriventris monsters (at least monsters next to their P. muralis relatives) to develop different coloring to adapt to environmental changes are still unknown, where their appearance comes from is no longer a mystery.

At least the lizards that are the Hulk don’t have to be exposed to extreme radiation to get their size, color and strength, unlike Bruce Banner himself.

Scientific Progress, 2024. DOI: 10.1126/sciadv.adk9315

Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top