2014年7月31日 星期四

機器人進度

蘋論:台灣須趕機器人進度

 
 
微軟老闆比爾蓋茲早在10年前就預言,下一波領頭的新產業將是機器人,是比目前的機械手臂更完整、更多元、更複雜、更親近人類的擬人機器人。機械手臂不能客製化,可以用來開刀、拆除炸彈、做危險的工作,但無法進入一般人的個人生活及家庭去工作。不久後的擬人機器人將在辦公室、家裡、公共場所做現在人做的工作,像是看家、打掃、照顧病人(長照問題或將解決)、泡咖啡、做飯、鋸樹、拔草、澆花、遛狗、帶小孩、臨櫃服務、清理核災、情趣機器人甚至可以陪主人性愛,而且還會表達情緒。

別落後先進國家

這個商機大的驚人,目前日本、美國相當領先,會跟人互動的擬人機器人已經做出原型,離商品化不遠。台灣也有大學和一些專家在打造機器人,只是政府有欠主動。希望科技部能全力幫助發展機器人產業,別落後先進國家太多。
日本最近在這方面的技術已獲得突破。大阪大學機器人專家石黑浩說:「電腦能力已超越人類,機器人很快就變得很聰明」。南韓的機器人能夠分析市場走向,還獲邀加入香港創投公司的董事會。石黑浩還說:「神經科學和認知科學的知識能打造出更像人類的機器人,一旦人與機器人成為朋友,兩者之間的界線便會消失。」 

將成人類必需品

機器人將會像智慧手機,成為人類生活的必需品。技術成熟之後,機器人更像人類,那時將出現機器人的倫理與法律問題,就像複製人問題。打壞機器人算不算殺人?主人若把機器人當作情人、好友、家人,產生移情作用,願為它做任何事,算不算心理變態(戀物癖)或精神疾病?
機器人將是絕對的功能性和絕對的擬人主義間的結合。問題是它越像人類,別人無法辨識誰是真人,就越引起人的焦慮。此外機器人無法進化,它被凍結在它與人的相似性上,但又是無性的或中性的,有如伺候皇帝的太監,這種人、機關係顯得詭異又彆扭。 

越逼真問題越大

擬人機器人的失修壞掉,象徵人類的死亡,在拋棄時,主人可能出現疊映到自身的死亡恐懼與焦慮。這些從來沒有過的困惑,將在機器人時代降臨到我們身上。 

2014年7月21日 星期一

Beyond Salty and Sweet: A Budding Club of Tastes






Beyond Salty and Sweet: A Budding Club of Tastes



Photo
CreditJoyce Hesselberth
Sweet, salty, sour and bitter — every schoolchild knows these are the building blocks of taste. Our delight in every scrumptious bonbon, every sizzling hot dog, derives in part from the tongue’s ability to recognize and signal just four types of taste.
But are there really just four? Over the last decade, research challenging the notion has been piling up. Today, savory, also called umami, is widely recognized as a basic taste, the fifth. And now other candidates, perhaps as many as 10 or 20, are jockeying for entry into this exclusive club.
“What started off as a challenge to the pantheon of basic tastes has now opened up, so that the whole question is whether taste is even limited to a very small number of primaries,” said Richard D. Mattes, a professor of nutrition science at Purdue University.
Taste plays an intrinsic role as a chemical-sensing system for helping us find what is nutritious (stimulatory) and as a defense against what is poison (aversive). When we put food in our mouths, chemicals slip over taste buds planted into the tongue and palate. As they respond, we are thrilled or repulsed by what we’re eating.
But the body’s reaction may not always be a conscious one. In the late 1980s, in a windowless laboratory at Brooklyn College, the psychologist Anthony Sclafani was investigating the attractive power of sweets. His lab rats loved Polycose, a maltodextrin powder, even preferring it to sugar.

Photo
Contrary to popular belief, there is no tongue map — responsiveness is present in all areas of the tongue.Credit Nature Publishing Group
That was puzzling for two reasons: Maltodextrin is rarely found in plants that rats might feed on naturally, and when human subjects tried it, the stuff had no obvious taste.
More than a decade later, a team of exercise scientists discovered that maltodextrin improved athletic performance — even when the tasteless additive was swished around in the mouth and spit back out. Our tongues report nothing; our brains, it seems, sense the incoming energy.
“Maybe people have a taste for Polycose,” Dr. Sclafani said. “They just don’t recognize it consciously, which is quite an intriguing possibility.”
Dr. Sclafani and others are finding evidence that taste receptors on the tongue are also present throughout the intestine, perhaps serving as a kind of unconscious guide to our behavior. These receptors influence the release of hormones that help regulate food intake, and may offer new targets for diabetes treatments, Dr. Sclafani said.
Many tastes are consciously recognized, however, and they are distinguished by having dedicated sets of receptor cells. Fifteen years ago, molecular biologists began figuring out which of these cells in the mouth elicit bitter and sweet tastes.
By “knocking out” the genes that encode for sweet receptors, they produced mice that appeared less likely to lap from sweet-tasting bottles. Eventually, the putative receptors for salty and sour also were identified.
In 2002, though, as taste receptors were identified, the evidence largely confirmed the existence of one that scientist had been arguing about for years: savory.
Umami is subtle, but it is generally described as the rich, meaty taste associated with chicken broth, cured meats, fish, cheeses, mushrooms, cooked tomatoes and seaweed. Some experts believe it may have evolved as an imperfect surrogate for detecting protein.
Since then, researchers have proposed new receptor cells on the tongue for detecting calcium, water and carbonation. The growing list of putative tastes now includes soapiness, lysine, electric, alkaline, hydroxide and metallic.
“The taste field has been absolutely revolutionized,” said Michael Tordoff, a biologist at the Monell Chemical Senses Center. “We’ve made more progress in the last 15 years than in the previous 100.”
One candidate for the next basic taste appears to have emerged as the front-runner: fattiness. The idea has been around for a while, and many scientists thought it was not a specific taste, more like a texture or an aroma.
But researchers recently identified two taste receptors for unsaturated fats on the tongue. And fat evokes a physiological response, Dr. Mattes has found that blood levels of fat rise when we put dietary fat in our mouths, even without swallowing or digesting it.
Hours after a meal, the taste of fatty acids alone can elevate triglyceride levels, even when the nose is plugged. But fat, like umami, does not have a clear, perceptible sensation, and it is hard to distinguish a texture from a taste.
Dr. Mattes says that fat may have a texture that we like (rich and gooey) and a taste that we don’t (rancid).
If so, the taste may serve as part of our sensory alert system. When food spoils, he notes, it often contains high levels of fatty acids, and the taste of them may be “a warning signal.”
Although there is still no consensus beyond sweet, salty, sour, bitter and savory, the research makes clear there is more to taste than a handful of discrete sensations on the tongue. Before long, scientists may have to give up altogether on the idea that there are just a few basic tastes.
“If you’re talking three, four, five, six, you can still call it a pretty exclusive club,” Dr. Mattes said. “If you start getting beyond that, is the concept really useful?”

2014年7月15日 星期二

書寫紙賺人眼淚

http://news.ltn.com.tw/news/life/breakingnews/1055694


2014-07-15  17:32
〔本報訊〕現代人大多利用電腦或數位載具紀錄大小事,但仍有人喜歡藉由手寫,感受紙張溫度,記錄生活中點滴情感。現在,更有一本筆記本,讓你不管紀錄什麼事,都能「感動落淚」。
  • 看似普通的筆記本,居然讓人不管寫任何東西上去,都要掉眼淚。原來是內含會催淚的「烯丙基化合物」,效果就跟切洋蔥一樣。(圖片擷自rocketnews24.com)
    看似普通的筆記本,居然讓人不管寫任何東西上去,都要掉眼淚。原來是內含會催淚的「烯丙基化合物」,效果就跟切洋蔥一樣。(圖片擷自rocketnews24.com)
  • 即使只是寫「布丁放在冰箱裡」也會讓人掉淚。(圖片擷自rocketnews24.com)
    即使只是寫「布丁放在冰箱裡」也會讓人掉淚。(圖片擷自rocketnews24.com)
日本一家公司開發出全新技術,利用奈米科技,將洋蔥精油中催淚的「烯丙基化合物」(allyl propyl compounds)融入高級書寫紙。使用者透過鉛筆和圓珠筆寫在紙上產生摩擦,化合物就會從紙張揮發,效果有如切洋蔥一般,讓人自然而然地流下眼淚。
目前這項技術申請了世界專利,且筆記本即將在日本上架。有網友戲稱,這種筆記本上市後,應該會成為惡整朋友的禮物吧。

相關影片請見:


任何在美國依法運營的公司都適用於美國法律管轄,無論該公司擁有的信息數據存儲是否在美國境內,其內容不享受美國憲法第四修正案保護

先前美國紐約地方法官令微軟公司交出存儲在愛爾蘭數據中心伺服器的數據,微軟宣布海外伺服器不受美國法律管轄並積極提供數據,美國司法部近日確認任何在美國運營的公司數據都處於美國法律的管轄範圍,即使是境外伺服器上的數據也必須遵照搜查令提供。
2014 年 4 月美國紐約南區法官向一名微軟郵件用戶發出傳票,傳票內容包括了這名用戶的全部郵件往來信息,這些信息存儲在微軟唯一都柏林的數據中心伺服器中。微軟公司認爲美國法庭發出的傳票對境外伺服器無效。該法官認爲傳票的效力等同於搜查令,根據美國法律的相關規定,任何公司和個人在接到搜查令後必須提供要求的消息,無論信息存儲在哪。
微軟就此事向美國聯邦法院提起上訴,美國司法部近日作出聲明稱,微軟、蘋果等公司認爲境外伺服器數據不受美國法律管轄的看法是錯誤的,針對這一爭議的基本原則是,任何在美國依法運營的公司都適用於美國法律管轄,無論該公司擁有的信息數據存儲是否在美國境內,其內容不享受美國憲法第四修正案保護。
微軟律師表示司法部的表態對於科技産業有著廣泛影響,國會沒有權力將搜查令的效力推廣至他國領土,微軟愛爾蘭數據中心的大門不會因美國政府發出的搜查令敞開大門。
題圖來自Obama administration says the world’s servers are ours

2014年7月8日 星期二

Faculty of Life Sciences and Computing

因為現在在翻譯書,所以看到此篇姓名等用原文.....
英國的學制有Faculty,此Faculty 包括三個學院School

Faculty of Life Sciences and Computing - London ...

www.londonmet.ac.uk › Faculties

倫敦城市大學在京舉辦大數據與網絡安全研討會

2014年07月07日21:34:04來源:環球網
分享到:
【環球網報道記者鄧景軍】2014年IEEE計算智能世界大會(WCCI)將於2014年07月06日在北京舉行,英國倫敦城市大學 (Londonmet)生命科學與計算機學院智能係統研究中心主任,博士生導師Hassan Kazemian教授將在本次大會做主旨發言。會前,該校北京辦公室邀請Hassan Kazemian教授舉行了一場大數據的技術研討會,金山雲,易寶支付,到到旅遊網,樂視大數據,北京全人視界等國內知名企業高層與嘉賓進行了精彩互動。本次研討會由英國商會董事、教育委員會主席屈敏女士主持。
作為Londonmet)計算機學院智能係統研究中心主人,Hassan Kazemian教授詳細介紹了他們的研究重點領域,包括軟計算生物信息學中的應用;軟計算的應用到無線/有線網絡,IT和信息安全,視頻流和分佈,基於位置的服務和移動計算;數據挖掘,虛擬學習環境(VLE),模式識別,自然語言處理,認知科學,生物識別技術和地理信息係統數據庫的性能,並行分佈式係統和基於代理的用於構建數據倉庫的方法;先進的網絡技術及其應用(如電子商務,內容管理係統,語義Web和Web服務);提高人群來源數據信息質量,人工智能輔助生活中的應用研究等。
在回答北京全人視界CEO張璽輝關於音視頻的傳輸安全和數據挖掘的問題時,Hassan Kazemian教授講到美國Youtube、亞馬遜等國外網際網路巨頭也都是根據自己平臺的業務發展規劃設計自己的產品模型,目前還沒有一套成型的數據跟蹤係統可以直接照搬。在接受環球網健康主編王志勝專訪時,Hassan Kazemian教授特別提到大數據在醫療健康領域大有可為,並以該校與一個慈善基金會合作開展的一個醫療項目作為案例做了分享。
帕金森綜合症患者的手部關節眾多,容易受肌肉僵直的影響,患者的手往往呈一種奇特屈曲的姿勢,掌指關節屈曲,導致手掌展開困難;而其它手指間的小關節伸直,又使手掌握拳困難。針對這種情況,倫敦城市大學大數據項目組通過觀察患者手指敲擊鍵盤的規律,收集到足夠多的樣本,通過機器學習和人工智能能夠掌握他們的打字錯誤數據,從而研究出一整套適合這類患者的輔助生活方式(Assisted living)。除了 ​​這類特殊患者之外,尤其是隨著老齡化社會的到來,大數據在健康領域的應用會越來越廣泛。Hassan Kazemian教授也講到,英國葛蘭素史克GSK公司在大分子生物學、DNA測序等、遺傳等醫療層面廣泛應用大數據,已經走在國際前列。
屈敏主席介紹,倫敦城市大學(Londonmet)非常重視培養學生實踐能力,很大的一部分精力或者說目標是放在讓實際的產業和教學之間,很多課程也都是跟企業聯合做項目,尤其是建築學、工業設計、藥學等該校的特色專業,和上海中醫藥大學、諾華制藥、奔馳汽車等機構都有長期穩定的合作。該校也希望中國的企業公司關注該校的畢業生,希望實現校企互動,讓優秀的海外留學人才學以致用,不再“海待”。
關於Hassan Kazemian教授
Hassan Kazemian教授,現任倫敦城市大學智能係統研究中心主任,並擔任博士生導師。計算機控制係統工程碩士學位、計算機智能博士學位。Kazemian教授除去在倫敦城市大學(Londonmet)任教,同時進行多項專業研究,如:生物人工智能(AI )的應用信息學(膜蛋白); IT安全和DoS攻擊探測; 性能和安全性的Web應用程序的優化; 小企業的IT安全政策; 提高人群數據存儲庫的信息質量; 輔助生活;情境感知移動計算;有線和無線;視頻數據流及分銷;人工智能機器人應用;人工智能的應用加工;數據挖掘和多領域數據倉儲,如英國的創意產業數據倉庫; 英國河流的流體動力學流建模。
Kazemian教授曾主持或參與多個國際性專業論壇,如:2013年參與IEEE研究與發展學生論壇,2012年主持的安全與密碼技術國際論壇,並向大會提交一份聯合文案;2012年主持計算機與信息科學國際論壇;2011年主持通訊軟計算應用國際會議(EANN及AIAI聯合論壇)等。
Kazemain 教授出版及參與的著作或發表文章近80餘冊,其中包括《專家體統預測與應用》(2013年7月);《人工智能基礎——語言建​​模框架》(2012年4月);《計算機和信息科學通訊》(2011年7月);《智能工程係統與計算控制論》(2009)等等。
關於倫敦城市大學智能係統研究中心(ISRC)
ISRC成立於2001年,該中心旨在推動研究的理論分析與智能和自適應係統的實際應用,包括模糊邏輯、神經網絡、遺傳算法和人工智能技術。


該中心成立至今吸引了約300萬英鎊(合3000萬人民幣)的研究經費,包括英格蘭高等教育撥款委員會、歐盟第七研發框架計劃(FP7)、英國工程與自然科學研究理事會、英國皇家學會、翡翠基金、發展基金、LDA、Knowledge Connect 及KTPs等機構。

2014年7月5日 星期六

a tricorder





In the fictional Star Trek universe, a tricorder is a multifunction hand-held device used forsensor scanning, data analysis, and recording data.
Three primary variants of the tricorder appear in Star Trek, issued by the fictional organization Starfleet. The standard tricorder is a general-purpose device used primarily to scout unfamiliar areas, make detailed examination of living things, and record and review technical data. The medical tricorder is used by doctors to help diagnose diseases and collect bodily information about a patient; the key difference between this and a standard tricorder is a detachable hand-held high-resolution scanner stored in a compartment of the tricorder when not in use. The engineering tricorder is fine-tuned forstarship engineering purposes. There are also many other lesser-used varieties of special-use tricorders. The word "tricorder" is a combination of "tri-" and "recorder", referring to its three device input keys, which by default cover GEO (geological), MET (meteorological), and BIO (biological) functions.[1]




Several startups and research projects claim they can approximate the functions of the tricorder, the handheld device used to instantly diagnose a disease or analyze the atmosphere of an alien world.
Science is close to realizing that universally handy handheld gadget
BUSINESSWEEK.COM|由 BARRETT W. SHERIDAN, MARK MILIAN 上傳

2014年7月4日 星期五

BMW 3D prints new thumbs for factory workers

BMW 3D prints new thumbs for factory workers

German car manufacturer put new technology in place to reduce strain on manufacturing-line workers' hands
BMW 3D printed thumb
BMW has turned to 3D printing to augment its workers and stop strain on limbs frequently found on manufacturing lines. Photograph: BMW
German car manufacturer BMW has turned to 3D printing to physically augment its car-plant workers, giving them stronger, augmented thumbs.
The 3D-printed apparel acts like support brackets for the workers’ thumbs, reducing strain and helping them to fit certain parts into the cars more easily.
Each "thumb" is created as a custom orthotic device using a portable 3D camera, which captures the unique size and shape of each line-worker’s thumb.

Lasers, plastic, scanners and thumbs

The scan is then used to build up a thumb guard made of a semi-flexible thermoplastic polyurethane plastic – a hybrid material mixture of hard plastic and soft silicone – which is create by a 3D-printing technique called selective laser sintering.
A laser is used to fuse plastic powder into layers, building up the structure one thin slice at a time until the full 3D structure is created.
3D printed thumb in locked position
Locked position holding the offending rubber plug that has been causing thumb strain. Photograph: BMW
The finished thumb guard flexes in a closed position. But because the structure is perfectly fitted to the wearer’s thumb the pieces lock into place when the digit is raised into a thumbs-up position.

Iron Man for the thumb

The locked splint resists strain and spreads the load of pushing something like a stiff rubber plug into holes in the car’s chassis – something that was causing pain and strain for production-line workers.
After small trials in the company’s Munich vehicle assembly plant yielded “very positive” feedback from workers, BMW is now looking to roll this and other schemes using custom built 3D-printed apparel to help production and prevent pain and injury.
3D printed thumb
The plastic locks together spreading the load of pushing the plug into position, which takes some force to do. Photograph: BMW

3D printing for the last 25 years

BMW has been using 3D printing techniques as part of its prototyping of parts and cars since 1989 with around 100,000 pieces created a year using a variety of different techniques at the Rapid Technology Centre in Munich.
This is not the first ergonomic aid BMW has created used 3D printing. The German automotive company created customised wheelchair seats for the British paralympic basketball team in 2012 using similar methods.
The creation of the new thumb cots is part of a project at the Department of Ergonomics at the Technical University of Munich.
Other projects have used 3D printing to replace limbs with cheap, adaptable prosthetics, along with a large number of other interesting objects and creations that were not possible using traditional manufacturing methods.

Tibetans get high-altitude edge from extinct Denisovans' genes 西藏人高原基因來自於遠古滅絕人類






Researchers have known for a while that many people alive today carry genes from human species other than Homo sapiens, the result of ancient interbreeding with Neanderthals and Denisovans. The specifics, though, have not been clear. But in one case they now are, for it is because of these occasional Denisovan ancestors that Tibetans thrive in Tibet http://econ.st/1j0IacI




西藏人高原基因來自於遠古滅絕人類

更新時間 2014年7月3日, 格林尼治標準時間11:47

西藏人
西藏人的高原基因來自於遠古已滅絕的人類
據《自然》期刊報告,現代人從遠古所繼承的一種基因,可以讓他們適應高原的生活。
據悉,這種遠古的人類已經滅絕。這種叫EPAS-1的基因變種可以影響人類血液中的氧氣,在西藏人當中十分普遍。
西藏人長年生活在海拔4000米的高原。
該DNA(脫氧核糖核酸)的序列與一種早已消失了的遠古人類丹尼索瓦人(Denisovans)的DNA相符合。
其實,包括我們自己在內的現代人類的許多人都攜帶已經滅絕了的遠古人類的DNA。
而這些遠古已滅絕的人類曾經和我們的非洲祖先「雜交」。
40萬年前出現的尼安德特人(the Neanderthals)曾生活在歐洲和西亞地區,直到3萬5千年前。
無論是尼安德特人還是丹尼索瓦人都對現代人的DNA有所貢獻。
而現在,研究人員通過研究血紅蛋白找到了EPAS-1基因與丹尼索瓦人之間的聯繫。
比如,當人體在海拔較高的高原時,體內血液中的氧氣水平就比較低,這時候EPAS-1基因就會告訴身體中的其他的基因活躍起來,包括生產額外的紅血球。
而這種EPAS-1基因的變體在西藏人中十分普遍,這可能和他們在數千年前移居到高原生活時所發生的一種自然的基因選擇。
明確證據
該文章的主要作者之一,加州大學的尼爾森教授說,他們找到了明確的證據這種基因來自丹尼索瓦人。
尼爾森告訴BBC,「如果你、我到海拔高緯度時,我們都將立即會經歷各種不同的不良身體反應。我們會喘氣困難,還可能會得高原病。」
「過一陣,我們的身體為了適應這一情況將會生產更多的紅血球。但是由於我們不適應高原環境,我們的身體可能將會製造許多紅血球。」
「我們的血液變得太粘稠,血壓也會升高,這樣就會有中風的危險,如果是孕婦還可能患妊娠毒血症」。
但西藏人就不會有這些問題,他們的身體不會製造過多的紅血球,因此血液也不會粘稠。
尼爾森教授的研究小組在2010年就發現了西藏人身體中的這種EPAS-1基因變體,但是研究人員當時無法解釋它為什麼與從其他現代人類身上找到的DNA序列不一樣。
因此,他們才從更遠古的人類染色體組序列當中去尋找答案。
研究人員把它同尼安德特人相比較,沒有找到匹配,但當同丹尼索瓦人比較時令人吃驚地找到了吻合。
尼爾森教授解釋說,人類祖先與丹尼索瓦人的「雜交」發生在很久以前。
而當西藏人的祖先移居到高原之後,丹尼索瓦人的DNA在他們的身體中產生了基因變體,並喜歡這種環境轉變。之後它便存在於今天大多數的西藏人身上。
尼爾森教授說,這是人類通過與遠古人類「雜交」後獲得的基因適應新環境的一種清楚和直接的例子。
編譯:凱露





Tibetans get high-altitude edge from extinct Denisovans' genes


Scientific ResearchTibetScience
High in the Himalayas, an ancient gene helps Tibetans thrive at altitude
Denisovans are extinct, but their genes live on in Tibetans
Tibetans provide more proof that early humans mated with Neanderthals and Denisovans
Forget climbing Mt. Everest — for most humans, just eking out a living on the harsh Tibetan plateau is challenge enough. But Tibetan people have thrived there for thousands of years, and a new study says it's thanks to a genetic adaptation they inherited from an ancient human relative.
The study, published Wednesday in the journal Nature, identifies a long segment of DNA shared by the extinct people known as Denisovans and modern-day Tibetans. The segment contains the gene scientists think gives Tibetans a lung up over lowlanders at high altitudes.


No one knew the Denisovans ever roamed the Earth until four years ago, when scientists sequenced the DNA of a finger bone unearthed in a cave in the Altai Mountains of southern Siberia. The genome exhibited similarities to that of modern humans and our extinct Neanderthal relatives, but it was different enough to be considered a distinct species.
Like Neanderthals, Denisovans mated with their human contemporaries, scientists soon discovered. People of Melanesian descent who today inhabit Papua New Guinea share 5% of their genetic makeup with the Denisovans.
Now it appears that Tibetans can also trace part of their ancestry to this mysterious group.


In the new study, scientists collected blood samples from 40 Tibetans and sequenced more than 30,000 nucleotides on a segment of DNA containingEPAS1, the gene that makes Tibetans so well-suited for life at high altitude. Then the scientists compared that sequence with those of 1,000 individuals representing the 26 human populations in the Human Genome Diversity Panel. They found the high-altitude gene in only 2 of the 40 Han Chinese people in the panel and no one else.
“Natural selection by itself could not explain that pattern,” said Rasmus Nielsen, a computational biologist at UC Berkeley and an author of the study. “The DNA sequence was too different from anything else we saw in other populations.”
So they investigated whether the gene might have been imported from extinct Neanderthals or Denisovans, and, bingo, they found a match.
But how did the gene end up in the genome of modern Tibetans? The scientists used computer models to test two different hypotheses. Were Denisovans and Tibetans descended from a common ancestor that gave the gene to both? Or did humans acquire the gene by mating with Denisovans?


Early humans and Denisovans probably diverged around half a million years ago, and it’s very unlikely that the gene could be maintained in both populations for so long, Nielsen said.
“By the process of recombination, DNA segments become shorter and shorter and shorter,” he said. “But here we have a very long segment that is shared. That’s very unlikely, statistically.”
Alternatively, the gene could have entered the Tibetan gene pool more recently via sex. Once transferred, the gene would have spread rapidly in the Tibetan population because of the merciless selective pressures of high-altitude living.
“Genetically, Han Chinese and Tibetans are very similar throughout the genome,” Nielsen said. “But for this particular gene, they are extremely differentiated from each other, which is something you only see with very strong or very recent selection.”


The reason Tibetans need EPAS1 is that their mountainous home — a crease of buckled crust thrust upward by the tectonic collision of India and Asia — lies about 15,000 feet above sea level, on average. Up there, the air contains 40% less oxygen than it does at low elevations.
Although previous studies had identified the importance of EPAS1, scientists still don’t know exactly what the gene does. They know only that it leads to lower levels of hemoglobin — the oxygen-toting protein in blood — in Tibetans who live at high altitude compared with people from low elevations who have acclimatized.
“That may sound counterintuitive,” said Nielsen — after all, wouldn’t you want more oxygen, and thus, more hemoglobin to deliver it? But people without the gene tend “overreact” at altitude.


“As we acclimatize, we’ll start to produce a lot of red blood cells,” he said, speaking for himself and other non-Tibetans. Too many, in fact. “That will expose us to various diseases like hypertension, increased risk of stroke and preeclampsia. There are very negative fitness effects of having too many red blood cells, and the Tibetans avoid them.”
So how do Tibetans get more oxygen? Presumably they don’t, Nielsen said, and scientists are still trying to understand the physiological mechanisms that allow them to cope.
But one thing is now clear: They owe their extraordinary fitness to a rogue gene introduced into the human genome from their long-lost cousins.
Abigail Bigham, an anthropologist at the University of Michigan who was not involved in the study, said now the search for Denisovan DNA should extend to other groups not represented in the Human Genome Diversity Panel.
“When they looked in Han Chinese, they saw it in only two individuals,” Bigham said. “But other populations in Central Asia or East Asia — there are 49 other ethnic minorities in China that have different genetic backgrounds — would have been interesting to look at as well.”
In any case, she said, the new study adds to a growing body of work that has reshaped the way scientists think about human evolution and our relationship to our extinct relatives.
For a long time, most scientists believed Neanderthals and Denisovans had nothing to do with modern humans. Now they realize that these species are responsible for introducing some of the genetic diversity that allowed people to adapt to unique environments.
“We’ve come full circle,” Bigham said. “Not only has there been interbreeding, but in fact that interbreeding has led to important functional changes in the human genome.”
For all things science, follow me @ScienceJulia