TEXTO:
When Sudan, the last northern white rhino bull, died
in March 2018, that left alive only two females of
the subspecies once common in Central and East
Africa.Both are descendants of Sudan and live in Kenya,
[5] and were considered infertile. But now, new hope is
emerging that extinction of the species can still be
prevented. Researchers have successfully created living
embryos in the laboratory from frozen sperm of the
northern white rhinoceros and egg cells from the southern
[10] white rhinoceros. It’s the most closely related
subspecies, with more than 20,000 southern rhinos living
in the wild.
Although such hybrid embryos are not pure northern
white rhinoceros, the researchers are optimistic. They
[15] plan to take egg cells from the still living northern
rhinoceros females in autumn of this year, and to fertilize
them with stored sperm from the same species.They
then intend to implant the oocytes into fertile southern
rhinoceros females in early 2019. This method is also
[20] used in human reproductive medicine.
Even if healthy rhinoceros calves can be
produced, whether the northern white rhino can be saved
in the long term remains unclear. As the sperm comes
from a few rhinoceros bulls, limited genetic diversity could
[25] endanger the health of a newly bred northern white rhino
population. Due to the smaller gene pool, such inbreeding
typically leads to higher rates of recessive disorders,
translating into higher death rates and poorer overall
health.
[30] Still, the research unit is hoping that stem cell
technology can create more eggs and sperm from the
skin cells of 12 northern whites, increasing the supply
and genetic variety. If the scientists pull it off, they’ll
both rescue a seemingly doomed animal and provide a
[35] blueprint for protecting other animals teetering on the
edge of oblivion.
WHEN SUDAN...Disponível em: https://www.dw.com/en/researcherscreate-hybrid-northern-white-rhino-embryos/a-44527410. Acesso em: 1 nov. 2018. Adaptado.
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