Divergence of flycatcher species understood through genetic mapping

Biologists are one step closer to understanding why one species of living organisms can be so different from another, despite common ancestry.

Looking into species divergence is key to understanding why at some point down the evolutionary timeline, one species becomes another, and in the end the two are so different that only infertile offspring can be produced. A zebra and mule can produce a zedonk, but these cannot reproduce, as a consequence of their genes.

Researchers at Uppsala University, Sweden, have studied the genetic make-up of the European pied flycatcher bird and the collared flycatcher. They found that it is the presence of distinct chromosomes, and not changes in individual genomes, that triggers the existence of a new species. Much of the genome is unchanged in the two species, and the sequencing of these birds’ DNA marks an important development in genetics; up until now, only ‘model organisms’ have been sequenced and analysed.

They have shown that there are only a couple of regions per chromosome which differ between the two species, and it is these parts of the chromosome which divide in meiosis and are responsible for the production of gender cells. So rather than the adaptation of individual genes, it is the small difference in a few chromosomes that results in a separation and divergence of two species.

This finding may well be a general one, proving useful to other studies in ecology, genetics and evolution. More details about this genetic mapping research can be found in the scientific publication Nature.