Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers at Graz University developed new model to explain the emergence of biological diversity

07.04.2017

The southern tip of Lake Tanganyika is the home of red, blue and yellow cichlids that belong to the genus "Tropheus". The yellow Tropheus have developed as a result of hybridisation between red and blue fish, as researchers at the University of Graz have demonstrated by population genetic analyses and re-breeding in the laboratory. But how has this new phenotype managed to prevail? Why did the yellow cichlids not just continue to mix with the blue and red ones? The researchers see the answer to this question in environmental fluctuations. They have now published their new "Shifting Barriers Model" in the scientific journal "Ecology Letters".

"It very rarely happens in nature that a new phenotype, that developed as a result of cross-breeding, continues to persist over many generations", says Univ.-Prof. Dr. Kristina Sefc from the Institute of Zoology at the University of Graz who is also the first author of this recent publication.


Yellow Tropheus of the population Ilangi, which has developed as a result of hybridisation between red and blue fish in Lake Tanganyika

www.pisces.at/Wolfgang Gessl

"A hybrid population with its own distinctive traits can only survive if there is no further hybridisation with the parent line."

It is possible, yet very rare, that this is achieved by mate choice, i.e. only specimens of the same phenotype are recognised as mating partners. More often, the new population differs from its predecessors in ecological terms and colonizes a new habitat, for example, because it prefers a more arid environment.

In addition, environmental changes that create natural barriers may also contribute to physical separation. The latter is described by the Graz scientists in their "Shifting Barriers Model" now published for the first time.

This model, which can be applied to all sorts of different organisms, is the result of research on the red, blue and yellow Tropheus populations in Lake Tanganyika. The investigated populations inhabit the rocky sections of the lake shore. The yellow ones can only be found along an approximately 30 kilometre long stretch limited at both ends by sandy sections, one of these being the estuary of the wide Lufubu River.

The fish are highly specialised in reference to their habitat. Sand, for example, is a physical barrier that prevents them from meeting their red and blue conspecifics populating other lake shore sections. Otherwise they would mate, as was indeed demonstrated in laboratory experiments.

But how did the hybridisation come about? "As a result of environmental fluctuations, the positions of barriers separating the different fish populations along the coastline have changed so that the red and blue species came into contact, while the resulting hybrids were immediately physically separated from the parent lineages", explains Sefc. Roughly 100 000 years ago, the water level was 400 metres lower, and the lake shore looked entirely different.

At that time, the Lufubu was not the barrier it is today. "The new phenotype probably appeared at that time", the researchers presume. This assumption is in line with the fact that several different populations have in turn formed among the yellow cichlids. This indicates that the hybridisation must have happened a very long time ago.

In their analyses, the zoologists were supported by their colleagues from the Institute of Chemistry at the University of Graz.

Publication:
Shifting barriers and phenotypic diversification by hybridization
Sefc, Kristina; Mattersdorfer, Karin; Ziegelbecker, Angelika; Neuhüttler, Nina; Steiner, Oliver; Goessler, Walter; Koblmüller, Stephan
Ecology Letters, DOI: 10.1111/ele.12766

Contact:
Univ.-Prof. Dr. Kristina Sefc
University of Graz
Institute of Zoology
Tel.: 0043 316/380-5601
E-mail: kristina.sefc@uni-graz.at

Weitere Informationen:

http://doi.wiley.com/10.1111/ele.12766 publication

Mag. Gudrun Pichler | Karl-Franzens-Universität Graz
Further information:
http://www.uni-graz.at

More articles from Life Sciences:

nachricht New technique for in-cell distance determination
19.03.2019 | Universität Konstanz

nachricht Dalian Coherent Light Source reveals hydroxyl super rotors from water photochemistry
19.03.2019 | Chinese Academy of Sciences Headquarters

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Stellar cartography

The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a Zeeman- Doppler-Image of the surface of the magnetically active star II Pegasi.

A special technique allows astronomers to resolve the surfaces of faraway stars. Those are otherwise only seen as point sources, even in the largest telescopes...

Im Focus: Heading towards a tsunami of light

Researchers at Chalmers University of Technology and the University of Gothenburg, Sweden, have proposed a way to create a completely new source of radiation. Ultra-intense light pulses consist of the motion of a single wave and can be described as a tsunami of light. The strong wave can be used to study interactions between matter and light in a unique way. Their research is now published in the scientific journal Physical Review Letters.

"This source of radiation lets us look at reality through a new angle - it is like twisting a mirror and discovering something completely different," says...

Im Focus: Revealing the secret of the vacuum for the first time

New research group at the University of Jena combines theory and experiment to demonstrate for the first time certain physical processes in a quantum vacuum

For most people, a vacuum is an empty space. Quantum physics, on the other hand, assumes that even in this lowest-energy state, particles and antiparticles...

Im Focus: Sussex scientists one step closer to a clock that could replace GPS and Galileo

Physicists in the EPic Lab at University of Sussex make crucial development in global race to develop a portable atomic clock

Scientists in the Emergent Photonics Lab (EPic Lab) at the University of Sussex have made a breakthrough to a crucial element of an atomic clock - devices...

Im Focus: Sensing shakes

A new way to sense earthquakes could help improve early warning systems

Every year earthquakes worldwide claim hundreds or even thousands of lives. Forewarning allows people to head for safety and a matter of seconds could spell...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Modelica Conference with 330 visitors from 21 countries at OTH Regensburg

11.03.2019 | Event News

Selection Completed: 580 Young Scientists from 88 Countries at the Lindau Nobel Laureate Meeting

01.03.2019 | Event News

LightMAT 2019 – 3rd International Conference on Light Materials – Science and Technology

28.02.2019 | Event News

 
Latest News

Levitating objects with light

19.03.2019 | Physics and Astronomy

New technique for in-cell distance determination

19.03.2019 | Life Sciences

Stellar cartography

19.03.2019 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>