The two species (Pseudotropheus emmiltos and Pseudotropheus fainzilberi ) are found in the north western part of Lake Malawi. Until now, the only known difference between them was the color of their dorsal fin. Many researchers believe that African cichlids recognize conspecifics from these kinds of colour differences, which are thought to result from sexual selection. However, recent mate choice experiments have shown that female P. emmiltos recognize males of their own species from P. fainzilberi males based on olfactory communication rather than color.
Some of the genes known to influence mating behavior through olfaction in other vertebrate species are genes of the major histocompatibility complex (MHC). These genes code for receptor that bound molecules produced by infectious agents and present them to specialized cells of the immune system which then launch an immune attack on the microbes. They are the most diverse genes found in vertebrate genomes and individuals of some species, including humans, are able to "smell" other individuals’ variability at these genes and adjust their mate choice in order to optimize the effectiveness of their offspring's immune system. Analysis of MHC genes between P. emmiltos and P. fainzilberi revealed that the two species were genetically more different at these sites involved in contacting and presenting molecules to immune cells than at other sites of the gene's DNA sequence that do not play functional roles.
These results show that natural selection has driven the evolution of these genes in different direction between the two species. Furthermore, the researchers showed that infecting parasites found on the two species were significantly different, as predicted based on the known immune function of MHC genes. "The mechanisms having produced the hundreds of species of East African cichlid fishes in a relatively short period of time are unclear", says Jonatan Blais, the senior author of the paper." This is one of the first genetic adaptive differences between closely related East African cichlid species identified. As such, it improves our understanding of the recent evolution of this incredibly diverse group of fish by pointing to a trait that not only diverged for adaptive reasons but may also be involved in mating behavior."
"The precise role that this divergence played in the evolution of reproductive isolation has yet to be studied", comments Louis Bernatchez, co-author of the study." But it offers an exciting new perspective in the study of African cichlids speciation ".
Andrew Hyde | alfa
Novel carbon source sustains deep-sea microorganism communities
18.09.2018 | King Abdullah University of Science & Technology (KAUST)
New insights into DNA phase separation
18.09.2018 | Ulsan National Institute of Science and Technology (UNIST)
Thin-film solar cells made of crystalline silicon are inexpensive and achieve efficiencies of a good 14 percent. However, they could do even better if their shiny surfaces reflected less light. A team led by Prof. Christiane Becker from the Helmholtz-Zentrum Berlin (HZB) has now patented a sophisticated new solution to this problem.
"It is not enough simply to bring more light into the cell," says Christiane Becker. Such surface structures can even ultimately reduce the efficiency by...
A study in the journal Bulletin of Marine Science describes a new, blood-red species of octocoral found in Panama. The species in the genus Thesea was discovered in the threatened low-light reef environment on Hannibal Bank, 60 kilometers off mainland Pacific Panama, by researchers at the Smithsonian Tropical Research Institute in Panama (STRI) and the Centro de Investigación en Ciencias del Mar y Limnología (CIMAR) at the University of Costa Rica.
Scientists established the new species, Thesea dalioi, by comparing its physical traits, such as branch thickness and the bright red colony color, with the...
Scientists have succeeded in observing the first long-distance transfer of information in a magnetic group of materials known as antiferromagnets.
An international team of researchers has mapped Nemo's genome, providing the research community with an invaluable resource to decode the response of fish to...
Graphene is considered a promising candidate for the nanoelectronics of the future. In theory, it should allow clock rates up to a thousand times faster than today’s silicon-based electronics. Scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) and the University of Duisburg-Essen (UDE), in cooperation with the Max Planck Institute for Polymer Research (MPI-P), have now shown for the first time that graphene can actually convert electronic signals with frequencies in the gigahertz range – which correspond to today’s clock rates – extremely efficiently into signals with several times higher frequency. The researchers present their results in the scientific journal “Nature”.
Graphene – an ultrathin material consisting of a single layer of interlinked carbon atoms – is considered a promising candidate for the nanoelectronics of the...
03.09.2018 | Event News
27.08.2018 | Event News
17.08.2018 | Event News
18.09.2018 | Materials Sciences
18.09.2018 | Materials Sciences
18.09.2018 | Information Technology