(c) flickr & ECohen
ナポレオンは1日4時間しか眠らなかったといわれているが，必要な睡眠の長さと関係する遺伝子が見つかった。ヨーロッパ7カ国の4,000人以上を対象とした研究で，睡眠パターンを質問票により調査し，これと相関する遺伝子変異を探索した。すると，ABCC9と呼ばれる遺伝子の特定の変異体のコピーを2つ持つ人は，睡眠時間がかなり短いことが分かった。この遺伝子がコード化するタンパク質は，心臓病や糖尿病の発症にも関わる。睡眠時間とメタボリックシンドロームには関係があるとされているが，この研究により共通の機序が見えてきた。（吉田素子）
The ABCC9 of Sleep
A Genetic Factor That Regulates How Long We Sleep
Legend has it that Napoleon never needed more than four hours of sleep at a stretch. Others only feel fully rested after 10 hours between the sheets. Clearly, individuals vary with respect to how much sleep they need. Indeed, sleep duration is influenced by many factors. Apart from seasonal and other variables, age and sex play a role, as does one’s sleep-wake cycle or chronotype, i.e. whether one is a lark (early to bed, early to rise) or the converse, an owl. An international team of researchers led by LMU chronobiologists Professor Till Roenneberg and Dr. Karla Allebrandt has now identified the first genetic variant that has a significant effect on sleep duration and is found frequently in the general population. The variant was discovered in the course of a so-called genome-wide association study, in which the researchers scanned individual genomes for variations that were correlated with sleep patterns.
More than 4000 people from seven European populations, from countries as diverse as Estonia and Italy, took part in the project, and filled out a questionnaire designed to assess their sleeping habits. Analysis of the genetic and behavioral data revealed that individuals who had two copies of one common variant of the gene ABCC9 generally slept for a significantly shorter period in an undisturbed environment than did persons with two copies of the other version. The gene ABCC9 codes for the protein SUR2, which forms the regulatory component of a potassium channel in the cell membrane.
［単語和訳］
Genetic：遺伝的 Regulates：～を制御する
Legend has it that：～という伝説がある Napoleon：ナポレオン at a stretch：続けて between the sheets：寝ている with respect to：～に関して duration：持続時間 Apart from：～は別として seasonal：季節の variables：変数 play a role：役割を果たす sleep-wake cycle：睡眠・覚醒サイクル chronotype：クロノタイプ（朝型，夜型といった概日リズムの型） i.e.：すなわち lark：ひばり early to bed, early to rise：早寝早起き converse：逆 researchers：研究者 chronobiologists：時間生物学者 variant：変異体 general population：一般集団 in the course of：～の過程で so-called：いわゆる genome-wide association study：全ゲノム関連解析 scanned：～を精査した were correlated with：～と相関した
diverse：多様な Estonia：エストニア took part in：～に参加した filled out：～に記入した questionnaire：質問票 assess：～を評価する behavioral：行動の significantly：著明に undisturbed：邪魔されない codes for：～をコードする protein：タンパク質 regulatory：調整する potassium channel：カリウムチャネル cell membrane：細胞膜
