Just seven northern white rhinoceroses remain — all in captivity — but could stem cells made from their tissues one day boost the animal's ranks?

Jeanne Loring at the Scripps Research Institute in La Jolla, California, and her team treated connective tissue cells from a 10-year-old female (Ceratotherium simum cottoni) with viruses that delivered four key human genes. The genes reprogrammed the adult cells into cells known as induced pluripotent stem cells (iPS cells). The authors used the same procedure to obtain iPS cells from the adult cells of an endangered drill monkey (Mandrillus leucophaeus).

The reprogrammed cells from both creatures generated the three different germ layers that give rise to all other tissues. The authors say that iPS cells from endangered animals could one day be used to make germ cells, such as sperm, for assisted captive breeding (see 'Stem cells spawn sperm cells').

Nature Methods 10.1038/NMETH.1706 (2011)