Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The Cichlids’ Egg-Spots: How Evolution Creates new Characteristics

09.10.2014

The evolution of new traits with novel functions has always posed a challenge to evolutionary biology. Studying the color markings of cichlid fish, Swiss scientists were now able to show what triggered these evolutionary innovations, namely: a mobile genetic element in the regulatory region of a color gene. Their results have been published in the latest issue of the renowned scientific journal Nature Communications.

Biological evolution is in general based on the progressive adaption of traits through natural or sexual selection. However, ever so often, complex traits with completely new functions arise such as insect wings, feathers or the placenta.


The anal fin of the haplochromine cichlid Astatotilapia burtoni bearing the characteristic egg-spots

Fig: Zoology, University of Basel


A female haplochromine cichlid while mouth-breeding

Fig: Anya Theis, Zoology, University of Basel

The evolution of such evolutionary innovations is often hard to explain relying solely on the model of progressive modification of already existing traits. Furthermore, it is largely unknown which genome modifications actually lead to evolutionary innovations.

A team of Basel researchers jointly lead by Prof. Walter Salzburger from the Department of Zoology and Prof. Markus Affolter from the Biozentrum at the University of Basel now clarified the genetic and developmental origins of an evolutionary innovation in African cichlids.

The males of over 1,500 species feature conspicuous color markings on their anal fins – so called egg-spots – that play a central role in the mating behavior of these mouth-breeding fish. Immediately upon spawning, the female gathers up her eggs into the mouth before fertilization.

The male then presents his egg-spots to which the female responds by snatching and bringing her mouth close to the male's genital opening – only now are the eggs being fertilized inside the female's mouth.

“Jumping genes”

The Basel biologists were able to show that the evolution of egg-spots is linked to the insertion of a mobile genetic element – a “jumping gene” – in the regulatory region of a newly identified pigmentation gene. These mobile elements are short DNA strings that are able to change their position within the genome and can influence the regulation of other genes

In the case of the cichlid's egg-spots, the presence of the “jumping gene” upstream of a pigmentation gene with the name fhl2b leads to an alteration in gene expression in pigmentation cells and therefore to the development of the characteristic egg-spot pattern on the male cichlids’ anal fin.

The scientists came to this conclusion after having induced the cichlids’ genome segment containing the mobile element into zebrafish embryos. In fact, they were able to locate the according expression in a specific group of pigmentation cells. “These results illustrate once more the importance of changes in gene expression in evolution”, comments Prof. Walter Salzburger the findings.

Original source
M. Emilia Santos, Ingo Braasch, Nicolas Boileau, Britta S. Meyer, Loic Sauteur, Astrid Böhne, Heinz-Georg Belting, Markus Affolter & Walter Salzburger
The evolution of cichlid fish egg-spots is linked with a cis-regulatory change
Nature Communications 5:5149 (10.1038/ncomms6149)

David Brawand et al.
The genomic substrate for adaptive radiation in African cichlid fish
Nature 513: 375-381.

Further information
Prof. Walter Salzburger, Department of Environmental Science, University of Basel, Zoology, phone: +41 (0)61 267 03 03, email: walter.salzburger@unibas.ch

Weitere Informationen:

http://www.unibas.ch/index.cfm?uuid=EFD2A894CFF39024457223916C8B6E46&type=se...

Olivia Poisson | Universität Basel

More articles from Life Sciences:

nachricht Newly designed molecule binds nitrogen
23.02.2018 | Julius-Maximilians-Universität Würzburg

nachricht Atomic Design by Water
23.02.2018 | Max-Planck-Institut für Eisenforschung GmbH

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Attoseconds break into atomic interior

A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.

In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...

Im Focus: Good vibrations feel the force

A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.

By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...

Im Focus: Developing reliable quantum computers

International research team makes important step on the path to solving certification problems

Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Basque researchers turn light upside down

23.02.2018 | Physics and Astronomy

Finnish research group discovers a new immune system regulator

23.02.2018 | Health and Medicine

Attoseconds break into atomic interior

23.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>