Egg-free surrogate hens produced to save rare breeds

Hens that do not produce their own chicks have been developed by researchers for use as surrogates to lay eggs from rare breeds using new gene-editing techniques.
The advance may help to boost breeding of endangered birds, as well as improve production of commercial hens, researchers said.
Researchers at the University of Edinburgh in Scotland used a genetic tool called TALEN to delete a section of chicken DNA. They targeted part of a gene called DDX4, which is crucial for bird fertility.
Hens with the genetic modification were unable to produce eggs but were otherwise healthy, the team found.
DDX4 plays an essential role in the generation of specialised cells - called primordial germ cells - which give rise to eggs.

Researchers said that donor primordial germ cells from other breeds could be implanted into the gene-edited chickens as they are developing inside an egg.

The surrogate hens would then grow up to produce eggs containing all of the genetic information from the donor breeds.
The surrogate chickens are the first gene-edited birds to be produced in Europe.
"These chickens are a first step in saving and protecting rare poultry breeds from loss in order to preserve future biodiversity of our poultry from both economic and climate stresses," said lead researcher Mike McGrew from the University of Edinburgh.
The study was published in the journal Development.