Researchers have deciphered the function of a gene necessary for the formation of neural structures in the head of vertebrates and their perception of the environment around them.
In an international collaboration - which included several research institutions led by Oxford University - the research team presented its findings in a study published in the famous journal Nature on May 18.
The closest living relative of vertebrates
According to a report published on the "Science Alert" website, some researchers believe that the oleanders, sea squirts or cetaceans (bottle-shaped marine animals) spend their lives attached to a fixed object on the ocean floor, and researchers believe that they are the closest living relatives of vertebrates.
But strangely enough, sea squirts do not have a real head. Instead, their central nervous system consists of blocks of neurons in the anterior and posterior parts of the body, with dorsal cords connecting them.
Sea squirts look like sponges, with no visible head or tail.
Sea spray is the name of a group of marine animals that are also called tunicates, and these animals are famous for their habit of spraying water through one of the two openings of the body.
The adult sea spray has a leathery, bottle-like body, and spends the rest of its life after puberty attached to stones, oysters, and some other fixed objects.
Tadpole showing bipolar tail neurons (green) (University of Innsbruck)
Zoologist Jut Rothbacher of the University of Innsbruck in Austria sees sea squirts as an evolutionary model for vertebrates, and says - in a press release published by the university on May 18 - that sea squirts resemble an evolutionary prototype for vertebrates, and their common ancestor may have been very similar to a caterpillar. Sea sprays.
Not all scientists agree with this, because it is controversial, but Rothbacher and his colleagues recently found evidence to support their ideas.
Their research found that the Hmx genes that encode a pair of neurons in sea squirrel larvae are linked to genes that code the clumps of neurons in the head of the simplest fish-like animals, the lamprey and lamprey, which formed the model organisms for the study.
The sea squirt usually passes through a larval stage before its growth is completed, and the larva looks like a frog's chick, and it is able to swim in its close surroundings, and the larva has a notochord that extends to the end of the tail.
The larva loses its early frog shape within days and settles on the sea floor, and soon develops into an adult form.
This is why lampreys are considered "living fossils" because they have been around for a long time with little change in species.
These marine animals are some of the first vertebrates, and are somewhat similar to eels.
Central gene preserved
The researchers took the idea one step further, by attaching the HMX genes to lamprey in the larva of a tadpole of a type of sea sprayer called Ciona intestinalis, and found that the gene helped drive the expression of bipolar-tailed neurons.
But in lampreys, or lollipops, the same genes helped drive the expression of sensory neurons in the skull.
The lamprey is an order of aquatic animals belonging to the infamous class, and they are primitive round-mouthed vertebrates that lack a jaw, while they have a funnel-shaped sucking mouth containing teeth, which attaches to the bodies of other fish and sucks their blood.
In zoology, lamprey is not always a real fish, because it is very different from other fish.
Although they affect nerves in different parts of the body, the similar function of the HMX genes in the lamprey suggests that they have a common evolutionary origin and may have played a role in the centrality of the nervous system.
"HMX has been shown to be a central gene that has been conserved," says zoologist Alessandro Benatti of the University of Innsbruck in the university's press release. "It has retained its original function and structure, and may have been found in this form in the common ancestor of vertebrates and sea squirts." .
lampreys are "living fossils" that have been around for ages with little change in species (Pixaby)
Research confirms that neurons share characteristics with spinal ganglion neurons derived from the neural crest in vertebrates, suggesting that migration previously thought to be unique to the vertebrate neural crest has much deeper evolutionary roots.