生物谷报道:时序和其它生理节奏内在周期性控制着人体苏醒与睡眠的循环生物钟,科学家们认为这种生理周期性也许已经进化到了能预见环境内的调控性短暂变化,但是有关生理周期性的两个方面:24小时的日夜周期以及每年季节变化的周期之间的关系,目前了解的并不太多。
在本期的Science(6月29日)杂志上,两个研究小组获得了突破性的发现:他们发现果蝇的一种变异能帮助这种果蝇进入一个名为“滞育”的类似冬眠的生长停止状态,这一发现连接了生理周期性的日夜周期和季节变化的周期。
在第一篇文章中,来自英国的莱斯特大学(University of Leicester)遗传学和生物学系的研究人员发现黑腹果蝇中有一个生理节律基因变异:timeless,携带这一变异的果蝇比野生型果蝇能更好地响应环境的变化。
通过进一步的将timeless基因引入不同的遗传背景,研究人员还发现timeless基因天然的和人工的等位基因都会影响果蝇对外部光度和温度作出反应。这一变异通过自然选择传遍了欧洲,这种变化改变了一个重要的生活史,从而也许增加了果蝇对季节条件变化的适应能力。
英文原文:
Science 29 June 2007:
Vol. 316. no. 5833, pp. 1895 - 1898
DOI: 10.1126/science.1138412
Natural Selection Favors a Newly Derived timeless Allele in Drosophila melanogaster
Eran Tauber,1* Mauro Zordan,2* Federica Sandrelli,2* Mirko Pegoraro,1,2 Nicolò Osterwalder,2 Carlo Breda,1,2 Andrea Daga,2 Alessandro Selmin,1,2 Karen Monger,1 Clara Benna,2 Ezio Rosato,1 Charalambos P. Kyriacou,1 Rodolfo Costa2
Circadian and other natural clock-like endogenous rhythms may have evolved to anticipate regular temporal changes in the environment. We report that a mutation in the circadian clock gene timeless in Drosophila melanogaster has arisen and spread by natural selection relatively recently in Europe. We found that, when introduced into different genetic backgrounds, natural and artificial alleles of the timeless gene affect the incidence of diapause in response to changes in light and temperature. The natural mutant allele alters an important life history trait that may enhance the fly's adaptation to seasonal conditions.
1 Department of Genetics, University of Leicester, Leicester LE1 7RH, UK.
2 Department of Biology, University of Padova, 35131 Padova, Italy.
* These authors contributed equally to this work.
Present address: Department of Pharmacology, University of Padova, Largo Meneghetti 2, 35131 Padova, Italy.
To whom correspondence should be addressed. E-mail: cpk@leicester.ac.uk
在第二篇文章中,来自意大利帕多瓦大学(University of Padova),英国莱斯特大学(University of Leicester),德国雷根斯堡大学(University of Regensburg)的研究人员在上一个研究的基础上进行了延伸研究,发现这一变异导致身体时钟机制中更稳定的蛋白质-蛋白质相互作用。