How is the zebrafish?

There is a tiny but surprising tropical fish called Danio Rerio, or Zebrafish, which personally fascinates me. Tiny in size, but giant in its possibilities as a biological model for many investigations, this little fish is leading a revolution in the world of biomedicine. And do not think I’ve used the words “surprising” and “revolution” for free, no, what’s up. Many scientists think the same, and you, after reading these lines, you will probably agree with it. Moreover, I would even add another adjective to the protagonist of this article: “miracle of nature”. And it is not for less, because this little fish is capable of regenerating injuries that for other animals would be permanent. For example, it is capable of completely regenerating severe spinal injuries in just eight weeks, it can also regenerate the heart and its functionality after having amputated it up to 20%, and what concerns us most, if it causes blindness, injuring both the retina and the optic nerve, it is able to regenerate those cells returning to see normally in less than a month.

Come on, after reading the above, I imagine that you will not be surprised that this fish has become the ideal biological model for many scientists, being key to study diseases such as muscular dystrophy, cardiac muscle degeneration, cystic fibrosis, Parkinson’s, Alzheimer’s, diabetes, different types of cancer, spinal cord injuries, aging, anemia, cholesterol processing, diseases of the immune system, degenerative diseases of the retina, etc.

How is the zebrafish?
Well, first of all, in case you do not know, I think it is appropriate to introduce you to our friend:
Its name is zebrafish or Danio Rerio, it belongs to the order of the Cypriniformes, to the family Cyprinidae (it is related to the carps and the barbels), and it comes from rivers of slow waters and lagoons of India and Bangladesh.

The body of these fish is elongated, not excessively flattened and with dorsal fin. They reach a maximum size of 6 cm. The color of these fish is silver or gold base, presenting above this base color between 5 to 9 blue stripes that traverse its body longitudinally. Hence its common name for zebrafish.
The males alternate the blue bands with the color of golden base, while the females alternate the blue stripes with the color of silver base. The belly is light colored. The females are more robust, with the belly more bulky, while the males are more stylized.

They are omnivorous fish, very active and fast. The female lays up to 200 eggs in the same spawning (the male fertilizes them once they are in the water). The eggs are transparent and hatch after approximately three days. His life expectancy is about three or four years.

Very well, and now that you know our little friend a little, let’s move on to more interesting things …

Why has this fish become the ideal biological model for many investigations?
The zebrafish began to be used as a biological model in the 70s, when the researcher George Streisinger, of the University of Oregon, used this fish to perform a series of pioneering studies related to the biology of development and genetics. At the beginning it was used mainly as a tool to study the development of organs in vertebrates, but the high degree of genetic and physiological similarity with the human being has been converted over the years into a great biomedical tool. Its popularity among researchers intensified dramatically when it was discovered, a decade ago, that it could be used on a large scale to identify new genes through mutational screening.

The qualities that have turned this fish into one of the vertebrate biological models par excellence, only surpassed by the mouse, are:

It has great genetic similarity to human. We share about 80% of the genome and eight out of ten of our diseases can be reproduced in it. All this allows the results obtained with the drugs tested in these animals to be potentially extrapolated to humans.
This genetic similarity allows us to use it as an animal model to find out the functions of some genes and reproduce in them biomedical models of human hereditary diseases.
Recently the complete genome of the zebrafish has been sequenced, observing that it has the highest number of genes coding for vertebrates, 26,479 genes, which is an advantage for its use in the laboratory.
It has the capacity to regenerate the organs that are partially amputated or damaged, thus becoming the ideal biological model to investigate regenerative processes.


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