Navigation Links
Adaptation to parasites drive African fishes along different evolutionary paths
Date:8/15/2007

Quebec City, Canada - An international team of scientists from Canada (Universit Laval), the U.K. (University of Hull, Cardiff University) and Spain (Do ana Biological Station), have discovered that a pair of closely related species of East African cichlid fishes a group of fish whose diversity comprising hundreds of species has puzzled evolutionary biologists for decades evolved divergent immune gene adaptations which might explain why they do not interbreed, despite living side by side.

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 ".


'/>"/>

Contact: Jonatan Blais
jonatan.blais.1@ulaval.ca
418-656-213-18455
Public Library of Science
Source:Eurekalert

Related biology news :

1. 15 generations of untrained jocks, couch potatoes show big physiological adaptations
2. Otter adaptations: How do otters remain sleek and warm
3. Protein offers way to stop microscopic parasites in their tracks
4. Measuring hidden parasites in falciparum malaria
5. Researchers at UGA provide first look at protein expression in Chagas disease-causing parasites
6. Malaria parasites develop in lymph nodes
7. How healthy is that marsh? Biologists count parasites
8. Bacterial protein shows promise in treating intestinal parasites
9. Hopkins scientists link immune response to ghost parasites and severely congested sinuses
10. Parasites impact goes beyond host to affect ecosystem
11. Scientists identify molecular events that drive cell senescence
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/19/2016)... DUBAI , UAE, April 20, 2016 ... can be implemented as a compact web-based "all-in-one" system ... in the biometric fingerprint reader or the door interface ... requirements of modern access control systems. The minimal dimensions ... the ID readers into the building installations offer considerable ...
(Date:4/14/2016)... April 14, 2016 BioCatch ... Detection, today announced the appointment of Eyal Goldwerger ... role. Goldwerger,s leadership appointment comes at a ... of the deployment of its platform at several of ... technology, which discerns unique cognitive and physiological factors, is ...
(Date:3/31/2016)... -- Genomics firm Nabsys has completed a financial  restructuring under ... M.D., who returned to the company in October 2015. ... including Chief Technology Officer, John Oliver , Ph.D., ... Vice President of Software and Informatics, Michael Kaiser ... Bready served as CEO of Nabsys from 2005-2014 and ...
Breaking Biology News(10 mins):
(Date:4/29/2016)... Denver, CO (PRWEB) , ... April 29, 2016 ... ... on addressing the necessary fundamentals to transform technology into a viable company, CereScan’s ... enable growth. Mr. Kelley, a recognized leader and mentor in the Denver ...
(Date:4/29/2016)... 29, 2016 Elekta is pleased ... to its industry-leading treatment planning software, is available for ... Monaco version 5.11 provides significant performance speed ... speeds up to four times faster than in previous ... industry,s gold standard Monte Carlo ...
(Date:4/28/2016)... Conn. (PRWEB) , ... April 28, 2016 , ... ... financing and ongoing support for Connecticut's innovative, growing companies, today announced the launch ... health and financial technology (fintech) companies. , “VentureClash looks to attract ...
(Date:4/28/2016)... ... April 28, 2016 , ... Morris Midwest ( http://www.morrismidwest.com ), ... manufacturers at its Maple Grove, Minnesota technical center, May 11-12. The event ... Almost 20 leading suppliers of tooling, accessories, software and other related technology ...
Breaking Biology Technology: