Scientists have transformed mutated yellow zebrafish into a standard type of fish with a pale yellow body and dark stripes by inserting pigment-producing genes into the fry.
In an intriguing “experiment,” they discovered that when inserting a similar human pigment gene into the fish, they also changed color similarly.
As with humans, the skin color of zebrafish is determined by pigment cells, which contain pigment granules called melanosomes. The quantity, size, and darkness of the melanosomes in each pigment cell will affect its skin color. For example, Europeans have fewer melanosomes, and these granules are smaller and lighter compared to those in West African populations, while Asians fall somewhere in between these two groups.
The yellow zebrafish have fewer, smaller, and lighter melanosomes compared to normal fish.
The Experiment
Keith Cheng from Penn State College of Medicine and his colleagues found that a mutation in a gene (causing it to function incorrectly) resulted in the zebrafish not producing the necessary protein to create pigment granules.
“A gene mutation stops the protein production machine,” Cheng explained.
However, when Cheng’s team inserted an unmutated version of the gene into 2-day-old yellow zebrafish embryos, they produced melanosomes, restoring their skin color to the familiar dark hue within just a few days.
Next, the research team explored HapMap, an online database of human gene profiles, and discovered a similar melanosome-producing gene in humans. They then tested this gene by inserting it into yellow zebrafish embryos, and these fish also returned to their familiar dark color.
“We hypothesize that the zebrafish darkened due to the similar function of the human gene that was inserted – these genes produce more, larger, and darker melanosomes,” Cheng noted.
Human Mutation
Similar to yellow zebrafish, light-skinned Europeans also possess a mutation in the gene that produces melanosomes, resulting in their skin having less pigment. Scientists speculate that the diversity of this gene may also explain the occurrence of blue eyes and light hair in some individuals.
However, Cheng stated that it is important to note that the mutations in humans and zebrafish are different – while the gene in zebrafish completely fails to produce the protein needed for melanosome production, the mutated gene in humans still functions, albeit less actively.
This discovery could lead to advancements in targeted therapies for malignant pigment tumors or research into methods of altering skin color without using chemicals or other harmful solutions.
Thuan An
