Ball Gregory F, Balthazart Jacques
Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD 21218, USA.
Philos Trans R Soc Lond B Biol Sci. 2008 May 12;363(1497):1699-710. doi: 10.1098/rstb.2007.0010.
Investigations of the cellular and molecular mechanisms of physiology and behaviour have generally avoided attempts to explain individual differences. The goal has rather been to discover general processes. However, understanding the causes of individual variation in many phenomena of interest to avian eco-physiologists will require a consideration of such mechanisms. For example, in birds, changes in plasma concentrations of steroid hormones are important in the activation of social behaviours related to reproduction and aggression. Attempts to explain individual variation in these behaviours as a function of variation in plasma hormone concentrations have generally failed. Cellular variables related to the effectiveness of steroid hormone have been useful in some cases. Steroid hormone target sensitivity can be affected by variables such as metabolizing enzyme activity, hormone receptor expression as well as receptor cofactor expression. At present, no general theory has emerged that might provide a clear guidance when trying to explain individual variability in birds or in any other group of vertebrates. One strategy is to learn from studies of large units of intraspecific variation such as population or sex differences to provide ideas about variables that might be important in explaining individual variation. This approach along with the use of newly developed molecular genetic tools represents a promising avenue for avian eco-physiologists to pursue.
对生理学和行为的细胞与分子机制的研究通常避免尝试解释个体差异。相反，目标一直是发现普遍过程。然而，要理解鸟类生态生理学家感兴趣的许多现象中个体差异的原因，就需要考虑这些机制。例如，在鸟类中，类固醇激素血浆浓度的变化对于与繁殖和攻击相关的社会行为的激活很重要。试图将这些行为的个体差异解释为血浆激素浓度变化的函数，通常都失败了。在某些情况下，与类固醇激素有效性相关的细胞变量很有用。类固醇激素靶标敏感性会受到诸如代谢酶活性、激素受体表达以及受体辅因子表达等变量的影响。目前，尚未出现一种通用理论，在试图解释鸟类或任何其他脊椎动物群体中的个体变异性时能提供明确指导。一种策略是借鉴对种内变异的大单位（如种群或性别差异）的研究，以提供关于可能对解释个体差异很重要的变量的思路。这种方法与新开发的分子遗传工具的使用，为鸟类生态生理学家提供了一条有前景的探索途径。
