MEMO to cloners: to boost your success rates, try using male cells.
Cloning an adult animal usually involves putting the nucleus from an adult cell into an egg that has been stripped of its chromosomes. However, progress has been hindered by the fact that “reprogramming” adult nuclei in this way has very low success rates.
To get around this problem, a team led by Peter Mombaerts and Elaine Fuchs at Rockefeller University in New York tried using adult skin stem cells, which are less differentiated and so should be easier to reprogram. The success rate was still very low, but…
