Puppy successfully born from frozen embryo

A puppy has been born from a frozen embryo using technology that could be used to conserve endangered wild species like wolves and foxes, U.S. researchers say. Klondike, the western hemisphere\'s first puppy born from a frozen embryo, is a beagle-Labrador retriever mix, and although neither of those breeds is endangered, Klondike\'s existence is exciting news for endangered canids, scientists at Cornell University reported Tuesday. Klondike\'s beagle mother was fertilized using artificial insemination, and the resulting embryos were collected and frozen until Klondike\'s surrogate mother, also a beagle, was ready to receive the embryo, they said. Because a dog\'s cycles are able to sustain a pregnancy only once or twice a year, being able to freeze canine embryos is especially important to coordinate timing for transfer into surrogates, researchers said. \"Reproduction in dogs is remarkably different than in other mammals,\" Alex Travis of Cornell\'s Center for Wildlife Conservation said. \"We\'re working to understand these differences so we can tackle issues ranging from developing contraceptives to preserving the genetic diversity of endangered animals through assisted reproduction.\" The process of freezing materials such as fertilized eggs or embryos -- cryopreservation -- may provide a tool to repopulate endangered species, the researchers said.