Rapid evolution: New findings on its molecular mechanisms

August 14, 2019

The mechanisms by which new species arise are still not fully understood. What are the evolutionary processes that drive the evolution of new species? Evolutionary biologists traditionally assumed that geographical barriers between animal populations play a decisive role (allopatric speciation): a species is physically separated into two or more isolated populations, thereby preventing gene flow between these groups. The subpopulations adapt to their respective habitats and evolve into independent species with different characteristics. In recent years, however, the evolutionary biologist Professor Axel Meyer from the University of Konstanz has not only been able to show that new species can evolve from a source population within a shared habitat and in the presence of gene flow (sympatric speciation), but that this type of speciation might be much more common than previously thought. His laboratory is investigating both the ecological and genetic mechanisms that facilitate sympatric speciation. In a recent publication in the scientific journal Molecular Biology and Evolution, Axel Meyer and his colleagues Paolo Franchini, Peiwen Xiong, Carmelo Fruciano, Ralf Schneider, Joost Woltering and Darrin Hulsey identify the decisive role that a kind of genetic switch, microRNAs, play in sympatric speciation.

Rapid evolution of cichlids

The researchers led by Axel Meyer analyze the Midas cichlid fish from Nicaragua's volcanic crater lakes as a model system in their research. Cichlids are known for their ability to adapt to new environments at an exceptionally rapid rate and to form new species. The new fish species originate from a population found in the large lakes of Nicaragua, but after colonizing several very small and young crater lakes, they adapted to new ecological niches, evolved new characteristics (e.g. a more elongated body or a different jaw) and evolved into a variety of new species in less than 22,000 years. A further distinctive feature of these Midas cichlids is that they evolved into different species within the same population, sometimes repeatedly, by adapting to different ecological niches within their small crater lakes. The Midas cichlids of Nicaragua are thus one of the best known examples for sympatric speciation. Within such a short time period new mutations are very unlikely to happen. This made finding a molecular mechanism that can bring about different body shapes, adaptations and thereby distinct ecological niches so difficult and interesting. The evolution of microRNAs and new target sites for them to regulate the expression of genes offers one potential molecular mechanism that can bring about very fast evolutionary change with very little genetic differences between the extremely young species.


The biologists from Konstanz carried out genetic analyses of five species of Midas cichlids from the crater lakes Apoyo and Xiloá. Here, they focused in particular on the function of the so-called microRNA - a non-coding ribonucleic acid that has a regulatory effect on gene expression. The researchers found an increased activity of microRNA in young fish one day after they hatched during a phase in which the fish bodies are formed. They analyzed the interaction between microRNA and gene expression, identifying specific pairs of microRNAs and genes that influence each other. The microRNA suppresses the expression of the target genes and thus has a regulatory effect on them: the more active a particular microRNA is, the more effectively the target gene is suppressed or "switched off". "Our research results provide strong evidence that extremely quickly evolving microRNA regulation contributes to the rapid sympatric speciation of Midas cichlids," says Paolo Franchini.

Link: https://academic.oup.com/mbe/advance-article/doi/10.1093/molbev/msz168/5545549Note to editors:

You can download pictures here:


Caption: The Midas cichlid fish from the crater lakes of Nicaragua are one of the the best known examples for sympatric speciation. They evolved from a source population into a variety of independent species in less than 22,000 years.


Caption: Researchers found an increased activity of microRNA in young fish one day after they hatched.

University of Konstanz

Related Science Articles from Brightsurf:

75 science societies urge the education department to base Title IX sexual harassment regulations on evidence and science
The American Educational Research Association (AERA) and the American Association for the Advancement of Science (AAAS) today led 75 scientific societies in submitting comments on the US Department of Education's proposed changes to Title IX regulations.

Science/Science Careers' survey ranks top biotech, biopharma, and pharma employers
The Science and Science Careers' 2018 annual Top Employers Survey polled employees in the biotechnology, biopharmaceutical, pharmaceutical, and related industries to determine the 20 best employers in these industries as well as their driving characteristics.

Science in the palm of your hand: How citizen science transforms passive learners
Citizen science projects can engage even children who previously were not interested in science.

Applied science may yield more translational research publications than basic science
While translational research can happen at any stage of the research process, a recent investigation of behavioral and social science research awards granted by the NIH between 2008 and 2014 revealed that applied science yielded a higher volume of translational research publications than basic science, according to a study published May 9, 2018 in the open-access journal PLOS ONE by Xueying Han from the Science and Technology Policy Institute, USA, and colleagues.

Prominent academics, including Salk's Thomas Albright, call for more science in forensic science
Six scientists who recently served on the National Commission on Forensic Science are calling on the scientific community at large to advocate for increased research and financial support of forensic science as well as the introduction of empirical testing requirements to ensure the validity of outcomes.

World Science Forum 2017 Jordan issues Science for Peace Declaration
On behalf of the coordinating organizations responsible for delivering the World Science Forum Jordan, the concluding Science for Peace Declaration issued at the Dead Sea represents a global call for action to science and society to build a future that promises greater equality, security and opportunity for all, and in which science plays an increasingly prominent role as an enabler of fair and sustainable development.

PETA science group promotes animal-free science at society of toxicology conference
The PETA International Science Consortium Ltd. is presenting two posters on animal-free methods for testing inhalation toxicity at the 56th annual Society of Toxicology (SOT) meeting March 12 to 16, 2017, in Baltimore, Maryland.

Citizen Science in the Digital Age: Rhetoric, Science and Public Engagement
James Wynn's timely investigation highlights scientific studies grounded in publicly gathered data and probes the rhetoric these studies employ.

Science/Science Careers' survey ranks top biotech, pharma, and biopharma employers
The Science and Science Careers' 2016 annual Top Employers Survey polled employees in the biotechnology, biopharmaceutical, pharmaceutical, and related industries to determine the 20 best employers in these industries as well as their driving characteristics.

Three natural science professors win TJ Park Science Fellowship
Professor Jung-Min Kee (Department of Chemistry, UNIST), Professor Kyudong Choi (Department of Mathematical Sciences, UNIST), and Professor Kwanpyo Kim (Department of Physics, UNIST) are the recipients of the Cheong-Am (TJ Park) Science Fellowship of the year 2016.

Read More: Science News and Science Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.