美国科学家的一项最新研究，为一种进化理论找到了依据，即灵长动物的繁殖竞争在精子运动性层面上发生。相关论文在线发表于英国皇家学会《交界》(Journal of the Royal Society Interface)杂志上。
领导该项研究的是美国加州大学尔湾分校和圣地亚哥分校的Michael Berns。他和同事在研究中发现，繁殖比较混杂的黑猩猩和猕猴精子的游动速度明显比人类和大猩猩的更快，力量也更大。
人类和大猩猩在一个繁殖周期中，雌性个体只会与一个雄性交配，而黑猩猩和猕猴一般都要与群体中的多个雄性交配。因此，后两者的雄性个体精子游动得越快越猛，理论上与卵子成功结合的几率就越大。论文第一作者Jaclyn Nascimento表示，“在一夫多妻或一妻多夫制的交配模式中，快速游动的精子是受到进化青睐的。这与我们在黑猩猩和猕猴中的研究测量相一致。”
研究发现，这四种灵长动物按精子力量和速度排序依次是猕猴、黑猩猩、人类和大猩猩。人类不是最慢的，这一点让研究人员大感惊讶。Berns说，“或许人类并不像自己认为的那样，总是一夫一妻制。”
Berns是“光镊”(laser tweezers，利用激光来捕获和操控单个原子、分子)技术的先驱之一，新的研究方法也是建立在改良后的光镊技术上。当精细胞被激光束捕获后，光线的强度会发生同步减弱，通过这种方式，研究人员能得以在不同动物精子摆脱光镊束缚时，精确测量它们产生的力。
Berns表示，“生物学家对精子竞争问题的兴趣由来已久，但要真正检验该理论，需要生物学家、物理学家和工程师的通力协作。”(科学网 任霄鹏）
原始出处:
Journal of the Royal Society Interface
10.1098/rsif.2007.1118
2007年7月24日
The use of optical tweezers to study sperm competition and motility in primates
Jaclyn M. Nascimento1, Linda Z. Shi2, Stuart Meyers3, Pascal Gagneux4, Naida M. Loskutoff5, Elliot L. Botvinick6, Michael W. Berns2, 6
1Department of Electrical and Computer Engineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
2Department of Bioengineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
3Anatomy, Physiology and Cell Biology Department, School of Veterinary Medicine, University of California, One Shields Avenue, Davis, CA 95616, USA
4Glycobiology Research and Training Center, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
5Omaha's Henry Doorly Zoo, 3701 South 10th Street, Omaha, NB 68107, USA
6Beckman Laser Institute, University of California, Irvine, 1002 Health Sciences Road, Irvine, CA 92612, USA
摘要
Optical trapping is a non-invasive biophysical tool which has been widely applied to study physiological and biomechanical properties of cells. Using laser ‘tweezers’ in combination with custom-designed computer tracking algorithms, the swimming speeds and the relative swimming forces of individual sperm can be measured in real time. This combination of physical and engineering tools has been used to examine the evolutionary effect of sperm competition in primates. The results demonstrate a correlation between mating type and sperm motility: sperm from polygamous (multi-partner) primate species swim faster and with greater force than sperm from polygynous (single partner) primate species. In addition, sperm swimming force linearly increases with swimming speed for each species, yet the regression relating the two parameters is species specific. These results demonstrate the feasibility of using these tools to study rapidly moving (μms−1) biological cells.
Keywords
primate sperm competition, laser tweezers, sperm swimming force
