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 New technology offers fast peptide synthesis
28.02.2017 | Massachusetts Institute of Technology

nachricht Biofuel produced by microalgae
28.02.2017 | Tokyo Institute of Technology

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Safe glide at total engine failure with ELA-inside

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded after a glide flight with an Airbus A320 in ditching on the Hudson River. All 155 people on board were saved.

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded...

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

New technology offers fast peptide synthesis

28.02.2017 | Life Sciences

WSU research advances energy savings for oil, gas industries

28.02.2017 | Power and Electrical Engineering

Who can find the fish that makes the best sound?

28.02.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>