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Hope for white rhinos

February 28, 2024 By EarthWise Leave a Comment

New hope for the northern white rhinos

There are only two northern white rhinos left in the world, and both of them are female.  The last male died in 2018. Northern white rhinos live to about 40 and one of the two remaining is 35 and the other 24.  The clock is ticking for the species.

Recently, scientists with the BioRescue consortium successfully used in vitro fertilization to impregnate a southern white rhino.  It was the world’s first IVF rhino pregnancy.

There is now some hope that IVF could be used to produce more northern white rhinos.  For various medical reasons, neither of the remaining two female rhinos can serve as a surrogate mother.  But there is a plan B.

For a number of years, BioRescue has been creating northern white rhino embryos with eggs from the remaining females and sperm that was collected from males before they died.  There are now 30 northern white rhino embryos in cold storage, and they are continuing to produce more.

The recent success with the southern white rhino IVF provides hope that southern white rhino females can act as surrogate mothers with implanted northern white rhino embryos.  The species are similar enough that it should work.

The plan is to select surrogates and implant them.  This should happen this year.  A rhino pregnancy lasts 16 months.  If this is successful, there could be northern white rhino babies in two or three years.  The scientists want the offspring to live with the surviving northern whites for years to learn the social behavior of its kind.

It is possible that these gentle, hulking creatures may get a new lease on life.

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Just two northern white rhinos are left on Earth. A new breakthrough offers hope

Photo, posted September 16, 2017, courtesy of San Diego Zoo Safari Park via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Saving The Sumatran Rhino | Earth Wise

January 2, 2023 By EarthWise Leave a Comment

The Sumatran rhinoceros is the smallest and most ancient rhino species and is the only surviving species with hair.  It is critically endangered.  Because of poaching and habitat destruction, there are fewer than 50 of them left in the wild and those are scattered in the rainforests of Sumatra and the Indonesian part of Borneo.  Mating encounters between surviving males and females are increasingly rare.

The last male Sumatran rhino in Malaysia died in 2019 but cell samples from that individual are the basis of an ambitious effort in bioengineering.

Researchers from the Max Delbruck Center in Germany are taking skin cells from the deceased rhino and turning them into stem cells.  The hope is to use these stem cells to derive egg and sperm cells to be the basis of assisted reproduction.  Fertilization would take place in a petri dish.  The resultant embryos would then be carried to term by surrogate rhino mothers.

The researchers have reported success generating induced pluripotent stem cells or IPS cells from the rhino skin samples.  IPS cells are able to divide indefinitely and can transform into any cell type in the body.

The next step is to try to cultivate primordial germ cells – the precursors of eggs and sperm.

This work is going on because it is increasingly difficult to preserve the Sumatran rhino population by gathering together remaining individuals in wildlife Reserves.  Females that have not been pregnant for a long time often become infertile because of cyst growth on their reproductive organs, and some are just too old to bear young.

It may take extraordinary efforts like these to save these animals from extinction.

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A second chance for the Sumatran rhino

Photo, posted April 30, 2008, courtesy of Willem V. Strien via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Resurrecting The Tasmanian Tiger | Earth Wise

September 16, 2022 By EarthWise Leave a Comment

Company plans to resurrect the Tasmanian Tiger

Tasmanian tigers earned their nickname because of the stripes along their back, but they were not felines.  In fact, they were carnivorous marsupials, the type of Australian mammal that raises its young in a pouch.

Tasmanian tigers, also known as thylacines, were once native to the Australian mainland, as well as the islands of Tasmania and New Guinea.  Dog-like in appearance, Tasmanian tigers were extensively hunted after European colonization.  The last known Tasmanian tiger died in captivity in 1936.

Nearly 100 years after its extinction, the Tasmanian tiger may live once again.  Scientists in Australia and the United States have launched an ambitious multimillion dollar de-extinction project to genetically resurrect the Tasmanian tiger.

In order to bring back the animal, researchers will have to take stem cells from a living species with similar DNA – like the fat-tailed dunnart – and use gene editing techniques to turn them into “Tasmanian tiger” cells – or the closest approximation possible.  The team will need new assisted reproductive technologies to use the stem cells to make an embryo, which will then have to be transferred into an artificial womb or a dunnart surrogate to gestate.  The research team is optimistic that there could be a hybrid baby Tasmanian tiger in 10 years. 

The ambitious project is a partnership between scientists at the University of Melbourne and the Texas-based company Colossal Biosciences.  This is the second de-extinction undertaking by Colossal Biosciences, which announced last year it planned to use its technology to recreate the woolly mammoth, and return it to the Arctic tundra.

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Scientists want to resurrect the extinct Tasmanian tiger

Tasmanian tiger: Scientists hope to revive marsupial from extinction

Photo credit: E.J. Keller, from the Smithsonian Institution archives, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

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