The variety of breeds in the database ranges from wild birds to commercial broilers and egg-layers. In addition, it includes a range of local breeds from almost every continent as well as strains bred by hobbyists in Germany. In the study, the research team analysed genetic diversity within and between populations. The study showed that genetic diversity is reduced both within the hobby breeds and in high-performing commercial breeds, especially in those bred for egg-laying. In contrast, in African, South American and some Asian and European breeds, there is still considerable genetic diversity. "It is important for the sustainability and flexibility of breeding that these very different breeds are preserved," said Professor Henner Simianer and Professor Steffen Weigend from the Center for Integrated Breeding Research at the University of Göttingen.