Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Surprising Findings in Fish Genome

09.04.2013
It is a popular aquarium fish: the platyfish, Xiphophorus maculatus. It is valued by researchers as an important model organism in the search for genetic trigger factors of skin cancer. Together with colleagues from the USA, University of Würzburg biochemist Manfred Schartl has decoded the genome of this fish species.
It varies in color from cornflower blue to orange, red or silver with a broad range of color patterns. The platyfish, also known as platy, is one of the most popular species of aquarium fish today. Besides its striking coloration, it has another characteristic: While the females of most fish species lay eggs, which are fertilized afterwards, the platy species is a livebearer. It can give birth to up to 100 young at a time.

An animal model of skin cancer

The fish species Xiphophorus maculatus is of interest to scientists for another reason: If you cross certain strains of this species with each other, their progeny always develops skin tumors. Due to the cross-breeding, the finely adjusted regulatory system of genes gets out of control, leading to the formation of cancer. The tumors produced in this way correspond to malignant melanoma in humans.

A few years ago, Manfred Schartl identified one of these oncogenes and described its properties. Together with researchers from Washington University St. Louis and Texas State University/USA, the head of the Department for Physiological Chemistry at the Biocenter of the University of Würzburg has now deciphered the complete genome of this fish species. The research is published in the current issue of the journal Nature Genetics.

"With our knowledge of the genome, we can now trace the participation and interplay of individual genes in the development of skin cancer. Even in the initial analysis, we have found several interesting candidates," says Schartl. This knowledge about the fish can be readily applied to humans: "The very genes that trigger skin cancer in human pigment cells are responsible for the development of melanoma in Xiphophorus," the geneticist explains.

20,000 genes – and some surprises

The research team identified 20,000 genes in the genome of Xiphophorus – about as many as are contained in the human genome. The comparison with related species of fish brought some surprises.

Like many other fish species, Xiphophorus exhibits complex behavioral patterns, e.g. with regard to the courtship of females, parental care of offspring, foraging and fighting behavior or the avoidance of threats. With respect to behavioral complexity, the fish greatly surpass the other so-called lower vertebrates, such as frogs, salamanders, snakes, turtles and lizards – although the latter are much more closely related to birds and mammals in the evolutionary tree.

Gene copies make complex behavior possible

Why this is the case remained a mystery for a long time. A possible explanation can be found in the genes that are associated with perception and cognition. Klaus-Peter Lesch, the head of the Department for Molecular Psychiatry at the University of Würzburg, has studied such genes in humans and in laboratory mice for several years. Schartl and Lesch found that many of the genes responsible for these areas exist in the platyfish as well.

This finding led the researchers to analyze the genomes of other fish in this respect as well. "To our surprise, we discovered that many of these genes do not only exist as a single copy in the genome of the fish as is the case in terrestrial vertebrates, but even in duplicate," says Schartl. They are relics of a whole genome duplication event in an ancestor of today's modern fish. According to the scientists, the additional second copy is now free to take on new responsibilities in brain function. Thus, the fish had a larger set of tools available for the development of complex behavioral patterns as compared to other vertebrates.

The same traits developed independently

The fact that Xiphophorus females give birth to live young was also of interest to the scientists. When they compared the fish genome with that of mice and other mammals in this respect, they came across a series of further surprises: Although the trait of giving birth to live young developed in mammals and fish independently in the course of evolution, you can find identical genes in their genome.

It is true that the genes important for placenta function, yolk formation or ovum maturation exhibit "unique molecular changes", but they also possess commonalities in the molecular detail. "If the same biological characteristics evolve completely independently of each other, this obviously requires the same or at least very similar changes down to the molecular level of proteins and genes," says Schartl.

The genome is the "blueprint" of life. The sequencing of the platyfish genome provides cancer researchers, ethologists and all biologists interested in this organism with new opportunities to better understand the genes and their complex interactions in many important biological processes or in cancer development.

The genome of the platyfish, Xiphophorus maculatus, provides insights into evolutionary adaption and several complex traits. Schartl M, Walter, RB, Shen Y, Garcia T, Catchen J, Amores A, Braasch I, Chalopin D, Volff J-N, Lesch K-P, Bisazza A, Minx P, Hillier L, Wilson RK, Fuerstenber S, Boore J, Searle S, Postlethwait JH and Warren W. Nature Genetics. March 31, 2013. doi:10.1038/ng.2604

Contact person

Prof. Dr. Manfred Schartl, Department of Physiological Chemistry I, T: +49 (0)931 31-84149, email:Opens window for sending email phch1@biozentrum.uni-wuerzburg.de

Gunnar Bartsch | idw
Further information:
http://www.uni-wuerzburg.de

More articles from Life Sciences:

nachricht Novel 'repair system' discovered in algae may yield new tools for biotechnology
29.07.2016 | Boyce Thompson Institute

nachricht Molecular troublemakers instead of antibiotics?
29.07.2016 | Christian-Albrechts-Universität zu Kiel

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Self-assembling nano inks form conductive and transparent grids during imprint

Transparent electronics devices are present in today’s thin film displays, solar cells, and touchscreens. The future will bring flexible versions of such devices. Their production requires printable materials that are transparent and remain highly conductive even when deformed. Researchers at INM – Leibniz Institute for New Materials have combined a new self-assembling nano ink with an imprint process to create flexible conductive grids with a resolution below one micrometer.

To print the grids, an ink of gold nanowires is applied to a substrate. A structured stamp is pressed on the substrate and forces the ink into a pattern. “The...

Im Focus: The Glowing Brain

A new Fraunhofer MEVIS method conveys medical interrelationships quickly and intuitively with innovative visualization technology

On the monitor, a brain spins slowly and can be examined from every angle. Suddenly, some sections start glowing, first on the side and then the entire back of...

Im Focus: Newly discovered material property may lead to high temp superconductivity

Researchers at the U.S. Department of Energy's (DOE) Ames Laboratory have discovered an unusual property of purple bronze that may point to new ways to achieve high temperature superconductivity.

While studying purple bronze, a molybdenum oxide, researchers discovered an unconventional charge density wave on its surface.

Im Focus: Mapping electromagnetic waveforms

Munich Physicists have developed a novel electron microscope that can visualize electromagnetic fields oscillating at frequencies of billions of cycles per second.

Temporally varying electromagnetic fields are the driving force behind the whole of electronics. Their polarities can change at mind-bogglingly fast rates, and...

Im Focus: Continental tug-of-war - until the rope snaps

Breakup of continents with two speed: Continents initially stretch very slowly along the future splitting zone, but then move apart very quickly before the onset of rupture. The final speed can be up to 20 times faster than in the first, slow extension phase.phases

Present-day continents were shaped hundreds of millions of years ago as the supercontinent Pangaea broke apart. Derived from Pangaea’s main fragments Gondwana...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Clash of Realities 2016: 7th Conference on the Art, Technology and Theory of Digital Games

29.07.2016 | Event News

GROWING IN CITIES - Interdisciplinary Perspectives on Urban Gardening

15.07.2016 | Event News

SIGGRAPH2016 Computer Graphics Interactive Techniques, 24-28 July, Anaheim, California

15.07.2016 | Event News

 
Latest News

Vortex laser offers hope for Moore's Law

29.07.2016 | Power and Electrical Engineering

Novel 'repair system' discovered in algae may yield new tools for biotechnology

29.07.2016 | Life Sciences

Clash of Realities 2016: 7th Conference on the Art, Technology and Theory of Digital Games

29.07.2016 | Event News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>