A few weeks ago the Mainichi
News on-line reported the following:
一卵性双生児:宇宙と地球、1年後の違いは NASA実験
毎日新聞 2015年03月28日 19時22分(最終更新 03月28日 20時24分)
見た目そっくり、遺伝情報も同じ双子の1人が宇宙、もう1人が地球で1年過ごしたら、2人にどんな違いが出てくるか−−。米航空宇宙局(NASA)は28日(日本時間)、宇宙と地球に分かれて暮らす一卵性双生児の宇宙飛行士を比べる史上初の実験を始めた。
被験者は、3回の飛行経験がある米国人宇宙飛行士のスコット・ケリー氏(51)と、スペースシャトル「エンデバー」の船長を務めた兄マーク・ケリー氏(51)。唯一の双子の宇宙飛行士で、顔もうり二つ。スコット氏が28日未明、ロシアのソユーズ宇宙船で打ち上げられ、国際宇宙ステーション(ISS)に到着した。
スコット氏は今年1月の記者会見で、「(微小重力の影響で身長が伸び)地球帰還直後は兄をちょっとだけ見下ろすことができる」と笑いを誘った。ISS滞在は通常半年以下で、1年の長期滞在と双子実験は、将来の月や火星探査なども視野に入れている。その絶好の被験者がケリー兄弟だった。
ISS内は、地球より重力が小さい微小重力状態で、宇宙放射線の影響も大きい。NASAによると、2人を対象に実施する研究は10テーマ。宇宙滞在が、視力や心臓、筋肉、判断能力などにどのような影響を与えるかや、食事の違いが腸内細菌に与える影響、インフルエンザワクチンの効果などを比較する。
宇宙航空研究開発機構(JAXA)の大島博・主幹研究員(宇宙医学)によると、NASAは今回の1年滞在を機に、宇宙飛行士らの遺伝子を網羅的に調べる研究に本格的に着手する。大島さんは「微小重力では骨が減るが、減りやすい人とそうでない人がいる。遺伝子レベルで違いが分かれば、火星探査の際に個別の予防策を取りやすくなる」と話す。【大場あい】
(試譯文)
For the twin, genetic codes were looking exactly
alike; if one of them spent one year in space and another spent on
earth, what kind of differences would come out for these two people - the National
Aeronautics and Space Administration (NASA) of the US on the 28th
(March) (Japan time) began the first-ever experiment to split up the living of
identical twin astronauts in space and on earth so as to make comparison.
The
subject were two American astronauts: Mr. Scott Kelly (51) who had 3 times of flight
experience and elder brother Mr. Mark Kelly (51) who had served as the caption
of the space shuttle "Endeavor", the only twin astronauts with faces that
looked exactly alike. By dawn on the 28th Scott was launched by the Russian
Soyuz spacecraft and arrived at the International Space Station (ISS).
Scott at a press conference in January this year invited a laugh in saying that "(growing taller due to the influence
of less gravity) I could slightly look down upon my elder brother after returning
to the earth". One stay at the ISS was usually less than six months. A long
stay of one year and doing experiments on the twins had the future explorations
on the moon and Mars in consideration. The ideal subject were the Kelly brothers.
In the ISS,
the gravity was smaller than that on earth, and it was in a micro-gravity state.
The space radiation also had great effects. According to NASA the study put
into effect would target at these two people in 10 themes: what kinds of
influence did a space stay would have on the eyesight, heart, muscle and the
judgment ability. Also the influence on intestinal bacteria due to the
difference in meals eaten, and the effects of the flu vaccine etc. would be compared.
According to Hiroshi Oshima, the chief researcher
(space medicine) of the Japan Aerospace Exploration Agency (JAXA), NASA would take
this one-year stay as an opportunity to initiate a study in earnest in checking
astronauts’ gene in full details. Mr. Oshima said that "bones would
decrease due to the minute gravity, but there are people who tend to decrease easily
and people who do not. If you know the difference at the genetic level,
individual preventive measures would become easy to take in the event of a Mars
exploration".
Obviously the research
results would be important in planning future space explorations.