Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The genes tell crows to choose partners that look alike

20.06.2014

Crows like to select mates that look alike. In a large-scale genomic study, published in Science today, a team of researchers led by Uppsala University found that this behaviour might be rooted in their genetic make-up, revealing a likely common evolutionary path that allows for separating populations into novel species.

What is the driving engine behind biodiversity? One and a half centuries years ago, Charles Darwin recognized that species are subject to evolutionary change. Now, we know that all aspects defining an organism are encoded in its genome. Yet, how new species emerge from slight genetic changes remains unanswered. Crows, for example, are all black or grey coated, and they exhibit a strong tendency to select partners that look alike.

All-black Carrion Crow Nestlings

All-black carrion crow nestlings from a German population west of the hybrid zone. When crossing the zone, plumage colouration changes rapidly to the grey-coated hooded type.

Credit: Jochen Wolf

The researchers identified an avian system - crows and ravens of the genus Corvus - that they used as an evolutionary model to decipher the genetic underpinnings of speciation. Central to this system is the independent recurrence of a pied colour-pattern in several species of the genus that stands in contrasts to the predominant all-black plumage in the clade.

In this study the researchers focused on the young end of the evolutionary spectrum investigating the genetic architecture of divergence between all black carrion crows (Corvus [corone] corone) and grey coated hooded crows (C. [c.] cornix) that still hybridize along a hybrid zone stretching across Europe and Asia.

Hybrid zones are natural evolutionary experiments where early processes of speciation can be studied. Where black and grey morphs come into contact, they form a well-known hybrid zone that is astonishingly narrow (15-150 km) and apart from minor shifts has been stably maintained over at least 100 years.

Previous small scale genetic analysis showed hardly any genetic differentiation between carrion and hooded crow across the entire species range that would exceed the level of differentiation between populations of the same taxon, leave alone justify species status.

In this study the researchers set out to find the decisive differences that stabilize the hybrid zone and eventually keep carrion and hooded crows apart using a plethora of approaches: they generated a genome backbone, performed population genetic analyses of whole genome data of many individuals, raised young crows to measure gene expression under controlled conditions and conducted functional histological characterization of growing feather follicles to have a closer look at melanocytes, the cells where color is made.

Consistent with the hypothesis of color-mediated isolation, we found that gene expression differed almost exclusively in growing feather follicles at the stage where color is deposited into the feathers. Genes involved in coloration were constitutively expressed higher in black crow than in their grey counterparts.

Screens of the more than 1 billion base pairs in the genome revealed very little difference between the two. Only 82 base pairs were diagnosticly different and 81 of them were concentrated in one genomic region coding for genes involved in coloration and visual perception.

- This finding suggests the exciting possibility that a mate-choice relevant trait, like coloration, might be genetically coupled to its perception which could be common one evolutionary path allowing for separating populations into novel species. Such a mechanism could be common for many other species with visually oriented mate choice, says Jochen Wolf, one of the lead authors of the study.

###

For more information, please contact

Jochen Wolf, tel: +46 18-471 4120, e-mail: Jochen.Wolf@ebc.uu.se

"The genomic landscape underlying phenotypic integrity in the face of gene flow in crows" is scheduled for publication in the journal Science on 20 June 2014.

Jochen Wolf | Eurek Alert!

Further reports about: coloration crows follicles genes genomic genus populations species

More articles from Life Sciences:

nachricht Nanoparticle Exposure Can Awaken Dormant Viruses in the Lungs
16.01.2017 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

nachricht Cholera bacteria infect more effectively with a simple twist of shape
13.01.2017 | Princeton University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Water - as the underlying driver of the Earth’s carbon cycle

17.01.2017 | Earth Sciences

Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

17.01.2017 | Materials Sciences

Smart homes will “LISTEN” to your voice

17.01.2017 | Architecture and Construction

VideoLinks
B2B-VideoLinks
More VideoLinks >>>