白犀牛聯(lián)合起來拯救北方瀕臨滅絕的犀牛

白犀牛聯(lián)合起來拯救北方瀕臨滅絕的犀牛

While the world watches two southern white rhinos that could serve as surrogates for northern white rhinos, researchers are making progress behind the scenes creating viable embryos.

當(dāng)全世界都在關(guān)注南方的兩頭白犀牛，它們可能成為北方白犀牛的代孕者時，研究人員卻在幕后創(chuàng)造出了可存活的胚胎。

In July 2018, A southern white rhino named Victoria gave birth to a healthy male calf, marking the first successful birth from artificial insemination of a southern white rhino in North America.

2018年7月，一頭名為維多利亞的南方白犀牛產(chǎn)下一頭健康的雄性幼崽，這是北美第一頭通過人工授精成功產(chǎn)下的南方白犀牛。

Photo: Tammy Spratt, photographer/San Diego Zoo Safari Park

Victoria is one of two southern white rhinos at San Diego Zoo Safari Park that were artificially inseminated in 2018, part of a long-term effort to save the northern white rhino from extinction. Although both mothers have been carrying southern white rhino babies, their pregnancies are part of a careful testing process for southern white rhinos to eventually serve as surrogate mothers of baby northern white rhinos. The other mother-to-be, Amani, is due in November or December.

維多利亞是圣地亞哥野生動物園2018年人工授精的兩頭南方白犀牛之一，這是拯救北方白犀牛免于滅絕的長期努力的一部分。盡管這兩位母親都懷上了南部白犀牛寶寶，但她們的懷孕是對南部白犀牛進行仔細(xì)測試的過程的一部分，最終將成為北部白犀牛寶寶的代孕媽媽。另一位準(zhǔn)媽媽阿曼尼的預(yù)產(chǎn)期是11月或12月。

Only two northern white rhinos, a distant subspecies, are alive; both are female but neither can bear a calf. The last male northern white rhino, named Sudan, was euthanized in March 2018 at a preserve in Kenya due to age-related health problems.

只有兩只北方白犀牛，一個遙遠(yuǎn)的亞種，還活著;它們都是雌性，但都不能生小牛。最后一頭雄性北方白犀牛名叫蘇丹，由于年齡相關(guān)的健康問題，于2018年3月在肯尼亞的一個保護區(qū)被安樂死。

Researchers hope that one day Victoria and Amani could serve as surrogate mothers, giving birth to a northern white rhino baby. They're optimistic a northern white calf could be born this way within 10 to 15 years, and the work could also be applied to other rhino species, including critically endangered Sumatran and Javan rhinos.

研究人員希望有一天維多利亞和阿曼尼能成為代孕媽媽，生下一個北方白犀牛寶寶。他們樂觀地認(rèn)為，在10到15年內(nèi)，一頭北方白犀牛將以這種方式出生，這項研究也可以應(yīng)用于其他犀牛物種，包括瀕臨滅絕的蘇門答臘和爪哇犀牛。

A breakthrough with embryos

胚胎研究取得突破

Researchers point out the calf in Victoria's ultrasound. (Photo: Tammy Spratt, photographer/San Diego Zoo Safari Park)

The zoo institute has the cells of 12 individual northern white rhinos stored at its "Frozen Zoo." Scientists hope to convert those preserved cells to stem cells, which could develop into sperm and eggs to be used to artificially inseminate the female southern white rhinos.

動物園研究所將12只北方白犀牛的細(xì)胞儲存在“冷凍動物園”里。科學(xué)家們希望將這些保存下來的細(xì)胞轉(zhuǎn)化為干細(xì)胞，這些干細(xì)胞可以發(fā)育成精子和卵子，用于人工授精南方白犀牛。

An international team of scientists made huge strides when they were able to harvest 10 eggs from the last two surviving female northern white rhinos, Najin and Fatu — who are currently living in a Kenyan national park under 24-hour guard. In late August, they revealed that seven of those eggs were successfully matured and artificially inseminated, according to a report from the Ol Pejeta Conservancy in Kenya where they live.

一個國際科學(xué)家團隊取得了巨大的進步，他們從最后兩只幸存的雌性北方白犀牛納金和法圖身上收獲了10個卵子。這兩只雌性北方白犀牛目前生活在肯尼亞的一個國家公園里，受到24小時的保護。據(jù)他們居住的肯尼亞奧佩杰塔自然保護協(xié)會(Ol Pejeta Conservancy)的一份報告顯示，8月底，他們發(fā)現(xiàn)其中7個卵子已經(jīng)成功成熟，并進行了人工授精。

Najin (left) and Fatu, the only two remaining northern white rhinos, graze together at Kenya's Ol Pejeta Conservancy in 2018. (Photo: Tony Karumba/AFP/Getty Images)

A study published in the Proceedings of The Royal Society B also offered hope that artificial insemination will be successful. Researchers analyzed DNA from living southern white rhinos and compared it with DNA from museum specimens of northern white rhinos. They discovered the two subspecies are more closely related than previously thought and crossbred for thousands of years after the species split.

發(fā)表在《英國皇家學(xué)會學(xué)報B》上的一項研究也帶來了人工授精成功的希望。研究人員分析了現(xiàn)存南方白犀牛的DNA，并將其與博物館里北方白犀牛標(biāo)本的DNA進行了比較。他們發(fā)現(xiàn)，這兩個亞種之間的親緣關(guān)系比之前認(rèn)為的更為密切，而且在物種分裂后的數(shù)千年里，它們一直在雜交。

"Everyone believed there was no hope for this subspecies," Hildebrandt told BBC News. "But with our knowledge now, we are very confident that this will work with northern white rhino eggs and that we will be able to produce a viable population."

“每個人都認(rèn)為這個亞種沒有希望了，”希爾德布蘭特告訴BBC新聞。“但根據(jù)我們現(xiàn)在的知識，我們非常有信心，這將與北部白犀牛卵的工作，我們將能夠產(chǎn)生一個可行的種群。”