Verb Master 動詞達人

Last Woollies Had Mammoth Mutations
世界最早的釘子戶 - 長毛象
By Christopher Intagliata on March 2, 2017

影音說明檔：https://drive.google.com/open?id=0B-Bg0auB-gcoX3NWTjhOcmlDeDQ

In their heyday(全盛時期), woolly mammoths(長毛象) blanketed(覆蓋) the Siberian steppe(西伯利亞大草原[stɛp]), Alaska and large parts of North America. But by 10,000 years ago, warming climates had turned many of the grasslands they grazed(吃草) into forest. And humans, well they weren‘t so friendly either - one mammoth provides quite a feast (一場盛宴). So the mammoths largely disappeared. Except there’s this one holdout(死硬派、抵死不從者) population. On an island in the Arctic Ocean, called Wrangel Island. Where the last mammoths hid out(躲藏在外)…for more than 6,000 years.
長毛象(woolly mammoths)的全盛時期(heyday)，牠們覆蓋(blanketed)了西伯利亞大草原(Siberian steppe)、阿拉斯加和北美大部分的土地，但是就在一萬年前，溫暖的氣候把牠們賴以為生的草原變成森林，加上人類也不是吃素的，一隻長毛象相當於一場盛宴(quite a feast)，所以長毛象大幅度的消失，除了一派打不死的釘子戶(holdout)，北極海(Arctic Ocean)上有一座島叫做Wrangel Island，最後長毛象遠遠躲藏在那(hid out)又多活了六千多年。

"So the pyramids have been built, they've started to grow tea in China, and civilization had formed, and here are these mammoths no one knew was there, for the longest period of time." Rebekah Rogers, an evolutionary geneticist at the University of North Carolina. "And then people finally found this island around 3,700 years ago, around the time they went extinct."
「金字塔已經建好了，中國開始種植茶樹，人類文明已經成形，而遠在那兒有一群不為人知、山中無甲子的長毛象」，北卡大學進化遺傳學家Rebekah Rogers這麼說道：「大約三千七百年前，人類終於發現這座島，大約就是在牠們滅絕(went extinct)的時候。」

Rogers and her colleague Montgomery Slatkin analyzed the genome from the tooth of one of those island mammoths, which lived 4,300 years ago. They compared it to the genome of a mainland mammoth, from much farther back, 45,000 years. And they found that harmful mutations had polluted the island mammoth‘s genome in that time interval. Mutations that led to the loss of smell receptors(嗅覺受體), and urine proteins(尿胺酸)—compounds they probably needed for social signaling and mate choice.
Rogers和她的同事Montgomery Slatkin分析島上其中一隻四千三百年前的長毛象牙齒的基因群組(genome)，然後和更久以前(much farther back)約四萬五千年前大陸的長毛象進行比對，他們發現在這段期間(time interval)，幾種有害的突變(mutations)汙染了這座島上長毛象的基因群，突變導致牠們失去嗅覺受體(smell receptors)和尿胺酸，尿胺酸是種化合物，用來發送選擇交配對象的社交信號(social signaling)

The animals also developed this satiny(綢緞般柔軟光滑的) coat, that shines in the light. A trait that‘s actually popular for pet breeders today, for rabbits and guinea pigs. And the reason for all these mutations? Rogers says there just weren’t enough individuals on the island—1,000 at the most, 300 at their lowest—to allow natural selection to run its course. So it wasn‘t survival of the fittest(最適者生存). It was survival of… whoever randomly survived. Which meant they accumulated a lot of mutations. None of which made them drop dead(猝死) - but they weren't all that fit, either. The study is in the journal PLoS Genetics.
這群動物還進化出如綢緞般柔軟光滑的(satiny)外皮(coat)，這是現代最受歡迎寵物的一大特徵(trait)，比方兔子和天竺鼠，為何會產生這種突變呢？Rogers說，這裡的長毛象最多一千頭，最少三百頭，數量不足以順自然法則發展(allow natural selection to run its course)，最適者生存(survival of the fittest)在這裡不適用，這裡的生存法則是隨機碰運氣的，也就是說，這裡累積了非常多種的突變，沒有一種突變會讓牠們猝死(drop dead)，但也不全都適合牠們，這項研究報告在PLoS Genetics期刊上發表。

Rogers says a similar process could happen for rare animals on Earth today, like cheetahs(獵豹), pandas, gorillas(非洲大猩猩). “If you have a very small population for a very long time you can get this accumulation of bad mutations in their genomes. And so we‘d expect to see the same effect for them. It does take a long time period to get a signal as big as what we saw in the mammoths, so the earlier we can intervene for those species, the better off(過得更好) they'll be."
Rogers說：「類似的過程也會發生在目前地球稀有動物身上，比方獵豹(cheetahs)、熊貓、非洲大猩猩(gorillas)，如果僅有稀少的數量，時間朝了就會累積不好的突變在牠們的基因群裡，所以我們可以合理預期相同的情況會發生在牠們身上，對長毛象，過了很長的過程才出現，所以我們越早介入(intervene)這些物種，對牠們來說會更好(better off)。」

As for those humans who, long ago, found this last holdout of mammoths on Wrangel Island? “We don‘t have direct evidence they hunted them, but you kind of wish that they had taken them back and domesticated(馴養) them.” There’s already one interested buyer(有興趣的買家). “Oh yes, if you can find one I would like to have one as a pet. Preferably(最好是['prɛfərəbli]) a little smaller so it fits in my house."
至於那些很早以前在Wrangel Island發現這些最後釘子戶長毛象的人類呢？「我們沒有直接證據證明這些人捕獵牠們，但似乎像要把牠們帶回家去飼養(domesticated)」，那兒已經有一位興趣的買家(interested buyer)，喔，「是啊，如果你能找到一隻，我就想買來當寵物，最好是小隻一點的，這樣才能住進我家。」

* 這位寵物買家就是Rebekah Rogers本人，但是她想要小隻一點的