Northern White Rhino: Assisted Reproductive Technology is expected to preserve endangered genes.

Scientists have been able to create hybrid embryos of the endangered northern white rhinoceros (NWR) and its next-of-kin subspecies using assisted reproduction techniques, according to a study published Friday in the British journal Nature Communications.
Although researchers have previously performed in vitro fertilization of large mammals such as horses, the study is the first example of successful in vitro culture of rhino embryos into the blastocyst.
the technology is expected to preserve the endangered gene, greatly increasing the likelihood of some preserving the northern white rhino gene.
the northern white rhinoceros is the world's most endangered mammal.
not long ago, the world's last male northern white rhino cessaree died, and the remaining two female northern white rhinos became the species's only remaining members on Earth.
, Italian scientist Caceres Cary, Thomas Hildebrand of the Leibniz Zoo and Wildlife Institute in Berlin, Germany, and colleagues bred hybrid rhino embryos through in vitro fertilization and formed embryonic stem cell lines using hybrid embryos.
the team first thawed the sperm of the cold-frozen male northern white rhinoceros, but because the number of oocytes (eggs) in female northern white rhinos was decreasing, the researchers were able to fertilize the male northern white rhino's sperm into the oocytes of its next cousin, the southern white rhinoceros (SWR), through a single sperm injection in the oocyte plasma.
, the researchers then cultured the resulting Northern-South mixed white rhino embryo into the sacembryo and frozen it for future transplantation into a female southern white rhino. The next challenge, the
team says, is how to put frozen embryos into a surrogate female southern white rhino cessis and successfully conceive and give birth.
, the researchers also plan to try to obtain oocytes from two remaining female northern white rhinos.
in a related commentary accompanying the paper, the scientists said the study "is expected to preserve the genes of the functionally extinct northern white rhinoceros subspecies."
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