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By Mariette le Roux and Amélie Bottollier-Depois
Paris (AFP) – Months after the death of Sudan, the last male northern white rhinoceros, scientists said Wednesday they have cultivated embryos containing eggs. DNA of its kind, hoping to save the subspecies of extinction.
With only two white rhinos (NWR) known to be alive today – both female infertile – the team hopes their revolutionary technique will lead to the recovery of a viable NWR breeding population [19659003] "Our goal is to have in three years the first calf NWR," said Thomas Hildebrandt, head of reproductive management at the Leibniz Institute for Research on Zoo and Wildlife in Berlin. considering 16 months of pregnancy, we have a little over a year to have a successful implantation. "
The team's work, using a two-meter (6.6 feet) egg-extraction device in the very first ryos test tube rhinoceros
Now Frozen they "have a very good chance of establishing a pregnancy once implanted in a surrogate mother," says Hildebrandt.
Hybrid embryos were created with frozen sperm from NWR dead males and southern eggs females of white rhinoceros (SWR), of which there are still thousands on Earth
The eggs were harvested from rhinos in European zoos.
The team now hopes to use the technique to collect eggs of the last two northern white rhinos – Najin and Fatu, the daughter and granddaughter of Sudan, who live in a Kenyan national park
Risk and Reward
By fertilizing these with white rhinoceros sperm and in implanting the resulting embryos in females carrying white rhinoceros, the team intends to create "Our findings indicate that ART (badisted reproductive techniques) could be a viable strategy for saving genes Northern white rhinoceros, almost extinct, "wrote the team in the journal Nature Communications
. The researchers asked permission to harvest eggs from Najin and Fatu in Kenya, hopefully before the end of the year.
But the procedure is not without risk: "we have to do a complete anesthesia, the animal is down for two Hildebrandt admits that" it's a pretty risky situation, "conceded Hildebrandt
"We are very afraid that something unexpected would happen, it would be a nightmare."
In the meantime, the team will practice, im planting some of their hybrid embryos in substitutes of SWR "to test the system."
All hybrids born in consequence could play a crucial future role as surrogates, sharing more genes with northern rhinos than purely southerly substitutes
. major impediment to NWR repopulation considered by team.
With only two NWR females and all available sperm of only four dead males, single TAR would likely lead to a population without the genetic diversity required for a
To this end, researchers hope to use stem cell technology to make eggs and spermatozoa from frozen skin cells of 12 unrelated northern white rhinos. "This will greatly expand the founding diversity of the future NWR population," said the team in a statement.
There is a pressure of time, they pointed out, with only two animals still there to socialize the babies in the mystery "It's a motivating aspect to succeed as soon as possible so that the calf we produce can grow with Najin and Fatu, "says Hildebrandt
Terri Roth and William Swanson of The Zoo and Botanical Garden of Cincinnati, in a commentary on the study, said that ART alone can not save a species of extinction.
"Impressive results in a petri dish do not easily translate into a healthy flock of offspring" "
" To reach this one, you have to navigate a non-trampled path, and it is unlikely A viable population of Northern White Rhinos is reestablished.
For researchers, however, a combination of antiretroviral therapy and stem cell therapy, could "provide a blueprint on how to save highly endangered species that have already declined to numbers that make conservation efforts impossible." conventional. "
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