Could the eyes of jellyfish provide clues to the genetic evolution of this organ? And how can stimulating cells be "specialized" neurons?
For those who enjoy the ocean as a vacation destination and to escape the heat - like the heat wave we first immersed ourselves in - jellyfish alerts ( Mesopotamia ) can cause distress and even induce visceral fear. But while these aquatic creatures have intrigued scientists even though they refuse to wake bathers, as two recent studies show; one on the genetic evolution of the eye, the other on how to move from nerve cells to Produce stimulating cells.
One eye, two eyes...or no eyes
There are some jellyfish (jellyfish) that have simple eyes; others, complex ones; don't even have eyes at all. According to recent research, jellyfish eyes have evolved separately and independently into different species over thousands of years, making them a model for studying how genetic traits are expressed.
That's what a U.S. research team led by Paulyn Cartwright, professor of ecology and evolutionary biology at the University of Kansas, and a team of scientists from other universities sought: to study how jellyfish eye evolution worked genetically, cellularly and morphologically . "Eyes evolved independently several times in jellyfish," explains
Cartwright. "We have long known that not all animals have a single origin of eyes, but we were surprised by how many times jellyfish evolved independently." ".
Cartwright and his collaborators plan to scientifically "dig deep" into evolutionary patterns to discover whether jellyfish used the same or different aspects of their genetic tool set to construct their eyes each time they evolved.
"Some jellyfish have very complex eyes. Eyes, like cameras, which form images, have a lens, a cornea and a retina,"
Cartwright said: "Jellyfish are ideal for this because they have a variety of eyes, from simple groups of light-sensitive cells to very complex eyes. Like cameras, they form images and have lenses, corneas, and retinas. ".
The researchers plan to analyze many jellyfish species in their University of Kansas lab to identify all the genes expressed in the individual cells of the jellyfish's different eyes to find out what different instances of jellyfish have in common with each other and what their What happens to the basic genetic components? "The cells themselves have their own identity," Cartwright said, and they are actually the result of the expression of many, many different genes, so we can sometimes miss an overall pattern when looking at individual genes. If we look at all the genes expressed in the cell and what this particular outcome is, that might give us a different level of information."
"That's why it's nice to see all these different levels and see what's similar and what's changed to really help us understand such a complex problem. Jellyfish are a great system for doing that because they're very This kind of experiment is easy to do. We can look at individual genes and how they are expressed; we can zoom in on all the genes expressed in these cells."
Specimen collection in the genomic era
The three researchers will travel to Panama, a hotspot for jellyfish biodiversity, to collect specimens and build a more detailed discovery tree of jellyfish (or evolutionary history).
There are many kinds of jellyfish, with thousands of species. Discovering their exact evolutionary history is a challenge, in part because much of this diversification occurred more than 500 million years ago," Cartwright said. Another challenge is sampling these creatures. Many of them live in the deep sea, and some It's incredibly small and hard to find... So we're very excited about the genomic era as we get more data, sequence more genes, and release more DNA sequences we're looking forward to. "We're getting very promising information about the relationships between some of these prisoners."
From neurons to stimulatory cells
On the other hand, Cornell University (in Ithaca, New York and Doha) is interested in the jellyfish's stimulatory cells, which are responsible for their "stinging sensation." Bathers must avoid contact with them, as contact with them is painful and may cause anaphylactic shock in some cases. These cells, known as cnidocitos or cnidoblastos, are also excellent models for understanding the emergence of new types of cells, according to research conducted at the university and published in the Proceedings of the National Academy of Sciences last May.
New genes acquire new functions to drive biodiversity
These radical cells evolved from their ancestors, neurons, said Leslie Babonis, assistant professor of ecology and evolutionary biology in the Department of Arts and Sciences and study leader Come. "The results show how new genes acquire new functions to drive biodiversity," he said.
babonis points out that understanding specialized cell types, such as radical cells, is one of the key challenges in evolutionary biology. For nearly a century, it has been known that cells develop from a group of stem cells called that also give rise to neurons (brain cells), but until now, no one knew how these stem cells decided to form neurons or cells. Babonis says understanding this process in living citizens can reveal the current developmental trajectory of citizens.
Reprogrammed Neurons
"Canines are the only animals with canines, but many animals have neurons," the teacher said. So she and colleagues at the University of Florida's Whitney Marine Bioscience Laboratory studied sea anemones, specifically sea anemones, to learn how to reprogram a neuron to create a new cell. "A unique characteristic of Native Americans is that each possesses a blast organ (a small pocket within the cell) that contains the harpoon that is fired and used to impale [their prey],"
babonis said. "These harpoons are made from a single protein that is also found only in dogs, so dogs appear to be the clearest example of how the origin of a new gene (encoding a single protein) can drive a new type of cell Evolution of types. "
Using the functional genome of the star sea anemone "nematode", researchers show that by inhibiting the expression of the neuropeptide RFamida in a subset of developing neurons and then reusing these cells as cells, the cells mature. Furthermore, the researchers showed that a specific germanium-regulated gene is responsible for both suppressing the neural function of these cells and activating specific properties of the hollow cells.
babonis said neurons and cells have similar shapes; both are secretory cells that move something out of the cell. Neurons secrete the neuropeptide , a protein that can quickly transmit information to other cells. The burghers secrete poisonous harpoons.
cells or neurons? "Just one gene acts as a photoswitch: when it's on, you get a little cell, and when it's off, you get a neuron,"
babonis said. "It's a fairly simple logic that controls the identity of the cell."
This is the first study to show that this logic exists in an quasar, , so this property likely regulated how cells differentiated from each other in early multicellular animals.
babonis and his lab are planning future studies to examine the scope of applications of this genetic switch in creating new types of cells in animals.
