Currently, cloning can only be performed with live cells, i.e. cells that were obtained from a living dog or five days after its death at the latest. Through a simple biopsy procedure, a small piece of tissue can be obtained from the dog, and cells from the tissue can be frozen (cryopreserved) for use in cloning research later on.


Once Sooam researchers confirm that the cells are indeed viable and clonable, which can take up to four weeks, the cloning research process begins. Dogs that have similar ovulation time, which can be predicted by measuring progesterone levels every day, are selected as egg donors and surrogate mothers. Eggs are collected from the egg donor through a procedure called ‘flushing.’ Once the eggs are collected, nuclei of the eggs, which contain DNA of the egg donor, is removed. Such procedure is called ‘enucleation.’ Then, injection of donor cell into the enucleated egg is performed followed by ‘fusion’ of the two cells. This fusion procedure produces a cloned embryo that is transferred into a surrogate dog (embryo transfer: ET). The whole process from flushing to ET takes less than a day. Pregnancy diagnosis is performed 30 days after ET through ultrasonography. Finally, a healthy cloned puppy is delivered around 60 days after ET. Once the puppy is born, DNA of the clone is matched with those of the egg donor, surrogate mother, and original. This is to make sure that the clone indeed has the same DNA as that of the original and not those of either the egg donor or surrogate mother.


There are many variables involved in dog cloning. Please refer to Cloning Technology section to learn why dog cloning is so difficult and how Sooam researchers have been able to optimize the experimental procedures.