Flycatchers’ genomes explain how one species became two

Why are hybrids sterile?

October 2012. Just how new species are established is still one of the most central questions in biology. In an article in the leading scientific journal Nature, researchers at Uppsala University in Sweden describe how they mapped the genomes of the European pied flycatcher and the collared flycatcher and found that it is disparate chromosome structures rather than separate adaptations in individual genes that underlies the separation of the species.

"We were surprised that such a large part of the genome was nearly identical in the two species," says Hans Ellegren, professor of evolutionary biology and director of the research team behind the new findings.

Interbreeding
The big question in species-differentiation research today involves the genetic background of how two evolutionary lines gradually come to diverge from each other and ultimately cannot produce fertile young. Horses and donkeys, for instance, can crossbreed and produce mules and hinnies, but something in the genome of the latter makes them infertile. There must therefore be DNA sequences from diverging evolutionary lines that are not compatible.

Genome sequence of flycatchers

Researchers at the Evolutionary Biology Centre, Uppsala University, are now presenting the genome sequence for the two flycatchers, which are the first organisms apart from so-called model organisms, to have their genome sequenced. They are also the first DNA sequences for a vertebrate to have been determined entirely by Swedish researchers and at a Swedish laboratory. 

Continued:  http://www.wildlifeextra.com/go/news/flycatcher-genome.html