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.
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.
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.
Prof. Walter Salzburger, Department of Environmental Science, University of Basel, Zoology, phone: +41 (0)61 267 03 03, email: email@example.com
Olivia Poisson | Universität Basel
Researchers identify potentially druggable mutant p53 proteins that promote cancer growth
09.12.2016 | Cold Spring Harbor Laboratory
Plant-based substance boosts eyelash growth
09.12.2016 | Fraunhofer-Institut für Angewandte Polymerforschung IAP
Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.
Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
09.12.2016 | Life Sciences
09.12.2016 | Ecology, The Environment and Conservation
09.12.2016 | Health and Medicine