Heritability of corticosterone response and changes in life history traits during selection in the zebra finch
Heritability of corticosterone response and changes in life history traits during selection in the zebra finch
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DOI：
10.1111/j.1420-9101.2005.01034.x
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发表时间：
2006-03-01
影响因子：
2.1
通讯作者：
Goldsmith, AR
中科院分区：
文献类型：
--
作者：
Evans, MR;Roberts, ML;Goldsmith, AR
脊椎动物通过神经内分泌应激反应对环境应激源做出反应，这涉及到糖皮质激素的产生。我们选择了独立的、重复发散的斑马雀品系，分别用于皮质酮对轻度应激源的高、低和控制反应。本试验表明，在前四个世代中，高代表现出约20%的显著已实现遗传力。然而，与对照组相比，低线显然没有明显变化。这种反应的不对称性可能是因为所有的鸟类似乎都表现出对它们所居住的环境越来越适应的事实，控制线和低线的皮质酮反应显著下降。尽管高、低品系之间的平均皮质酮滴度存在2-3倍的差异，但不同群体的成年雄鸟的睾酮滴度并没有观察到差异。此外，在所测量的任何生活史变量上，品系之间都没有一致的、显著的差异--每窝产下的卵数、每对产下的窝或窝的数量、每次繁殖尝试产生的雏鸟的数量，以及任何蛋、雏鸟和雏鸟的死亡率。这些结果强调了这样一个事实，即鸟类生理系统变异的基础机制可以通过选择来修改，以应对环境之间的差异。这为鸟类的生理系统增加了额外的灵活性，使其能够对环境环境做出反应。
Vertebrates respond to environmental stressors through the neuro-endocrine stress response, which involves the production of glucocorticoids. We have selected independent, duplicate divergent lines of zebra finches for high, low and control corticosterone responses to a mild stressor. This experiment has shown that over the first four generations, the high lines have demonstrated a significant realized heritability of about 20%. However, the low lines have apparently not changed significantly from controls. This asymmetry in response is potentially because of the fact that all birds appear to be showing increased adaptation to the environment in which they are housed, with significant declines in corticosterone response in control lines as well as low lines. Despite the existence of two- to threefold difference in mean corticosterone titre between high and low lines, there were no observed differences in testosterone titre in adult male birds from the different groups. In addition, there were no consistent, significant differences between the lines in any of the life history variables measured - number of eggs laid per clutch, number of clutches or broods produced per pair, number of fledglings produced per breeding attempt, nor in any of egg, nestling and fledgling mortality. These results highlight the fact that the mechanisms that underlie variation in the avian physiological system can be modified to respond to differences between environments through selection. This adds an additional level of flexibility to the avian physiological system, which will allow it to respond to environmental circumstances.