Guyomarc'h C, Lumineau S, Richard J P
UMR 6552 Ethologie, Evolution, Ecologie, Rennes, France.
Chronobiol Int. 1998 May;15(3):219-30. doi: 10.3109/07420529808998685.
In conditions of constant darkness, interindividual variability in the clarity of circadian rhythmicity was observed in sexually immature young quail, with birds classified as more or less rhythmic or arrhythmic. The relative clarity of this circadian rhythm was observed on the actograms by measurement of the autocorrelation coefficient ratio over 12 cycles. Autocorrelation coefficients were calculated from sequential series of total activity over 12-minute periods. Crosses of selected phenotypes with different clarities of rhythmicity were conducted in order to study the possibility of selection of this characteristic. From a random population (N = 42, twice), pairs of the most rhythmic birds (3 families), and pairs of arrhythmic birds (4 families) were reared. Autocorrelation coefficient ratios of F1 birds from rhythmic families (N = 54) were greater than those of F1 birds (N = 48) from arrhythmic families (t-test, p < .0001). These ratios in offspring were significantly correlated with that of the mean parent of each clutch of siblings (N = 102, r = .35, p = .0003). This result was maintained in a second generation (F2) of birds, for which significant differences in expressed rhythmicity were observed. That is, autocorrelation coefficient ratios of F2 birds from two rhythmic families (N = 30) were greater than those of F2 birds from arrhythmic families (N = 20) (t-test, p = .039). Comparison of F2 outbred and inbred birds from rhythmic pairs showed greater values of autocorrelation coefficient ratios in the case of inbred birds (N = 16) than for outbred birds (N = 30; t-test, p = .036). There was no difference between outbred (N = 20) and inbred birds (N = 15) from arrhythmic pairs. Therefore, selection of a rhythmic strain seems possible, whereas crosses between two arrhythmic birds may also give rise to rhythmic birds. Comparisons between rhythmic birds of different families did not show differences in the free-running period of the circadian rhythm, which is true also for rhythmic birds bred from two arrhythmic parents. Therefore, our selection procedure did not seem to be based on the characteristics of the pacemaker itself, but rather on a downstream event. Although the parents were not selected on the basis of quantity of activity per cycle or on the duration of the active phase, significant differences among the offspring of different families were shown.
在持续黑暗的条件下，观察到性未成熟的幼鹌鹑在昼夜节律清晰度方面存在个体间差异，这些鹌鹑被分类为节律性较强、较弱或无节律。通过测量12个周期内的自相关系数比，在活动记录图上观察到这种昼夜节律的相对清晰度。自相关系数是根据12分钟时间段内的总活动顺序系列计算得出的。为了研究选择这一特征的可能性，对具有不同节律清晰度的选定表型进行了杂交。从一个随机种群（N = 42，分两次）中，选取了节律性最强的鸟对（3个家族）和无节律的鸟对（4个家族）进行饲养。来自节律性家族的F1代鸟（N = 54）的自相关系数比高于来自无节律家族的F1代鸟（N = 48）（t检验，p <.0001）。后代的这些比值与每个同胞窝的平均亲本的比值显著相关（N = 102，r =.35，p =.0003）。这一结果在第二代（F2）鸟中也得到了维持，在F2代鸟中观察到了表达节律性的显著差异。也就是说，来自两个节律性家族的F2代鸟（N = 30）的自相关系数比高于来自无节律家族的F2代鸟（N = 20）（t检验，p =.039）。对来自节律性鸟对的F2代杂交和近亲繁殖鸟的比较表明，近亲繁殖鸟（N = 16）的自相关系数比值高于杂交鸟（N = 30；t检验，p =.036）。来自无节律鸟对的杂交鸟（N = 20）和近亲繁殖鸟（N = 15）之间没有差异。因此，选择一个节律性品系似乎是可能的，而两只无节律的鸟杂交也可能产生有节律的鸟。不同家族的有节律鸟之间的比较未显示昼夜节律的自由运行周期存在差异，由两只无节律亲本培育的有节律鸟也是如此。因此，我们的选择程序似乎不是基于起搏器本身的特征，而是基于下游事件。尽管亲本不是根据每个周期的活动量或活动期的持续时间来选择的，但不同家族的后代之间仍显示出显著差异。
