TY - JOUR
T1 - Lab mice in the field: unorthodox daily activity and effects of a dysfunctional circadian clock allele
AU - Daan, S.
AU - Spoelstra, K.
AU - Albrecht, U.
AU - Schmutz, I.
AU - Daan, M.
AU - Daan, B.
AU - Rienks, F.
AU - Poletaeva, I.
AU - Dell'Omo, G.
AU - Vyssotski, A.
AU - Lipp, H.P.
N1 - Reporting year: 2011
Metis note: 5059; WAG; BB
PY - 2011
Y1 - 2011
N2 - Daily patterns of animal behavior are potentially of vast functional
importance. Fitness benefits have been identified in nature by the association
between individual timing and survival or by the fate of individuals after experimental
deletion of their circadian pacemaker. The recent advances in unraveling
the molecular basis of circadian timing enable new approaches to natural selection
on timing. The investigators report on the effect and fate of the mutant Per2Brdm1
allele in 4 replicate populations of house mice in a seminatural outside environment
over 2 years. This allele is known to compromise circadian organization and entrainment
and to cause multiple physiological disturbances. Mice (N = 250) bred from
Per2Brdm1 heterozygotes were implanted subcutaneously with transponders and
released in approximately Mendelian ratios in four 400 m2 pens. An electronic
system stored the times of all visits to feeders of each individual. The study first
demonstrates that mice are not explicitly nocturnal in this natural environment.
Feeding activity was predominantly and sometimes exclusively diurnal and spread
nearly equally over day and night under the protective snow cover in winter. The
effect of Per2Brdm1 on activity timing is negligible compared to seasonal changes in
all genotypes. Second, the Per2Brdm1 allele did not have persistent negative effects
on fitness. In the first year, the allele gradually became less frequent by reducing
survival. New cohorts captured had the same Per2Brdm1 frequency as the survivors
from previous cohorts, consistent with an absence of an effect on reproduction. In
the second year, the allele recovered to about its initial frequency (0.54). These
changes in selective advantage were primarily due to female mice, as females lived
longer and the sex ratio dropped to about 25% males in the population. While it is
unknown which selective advantage led to the recovery, the results caution against
inferences from laboratory experiments on fitness consequences in the natural
environment. It also demonstrates that the activity of mice, while strictly nocturnal
in the laboratory, may be partially or completely diurnal in the field. The new
method allows assessment of natural selection on specific alleles on a day-today
basis.
AB - Daily patterns of animal behavior are potentially of vast functional
importance. Fitness benefits have been identified in nature by the association
between individual timing and survival or by the fate of individuals after experimental
deletion of their circadian pacemaker. The recent advances in unraveling
the molecular basis of circadian timing enable new approaches to natural selection
on timing. The investigators report on the effect and fate of the mutant Per2Brdm1
allele in 4 replicate populations of house mice in a seminatural outside environment
over 2 years. This allele is known to compromise circadian organization and entrainment
and to cause multiple physiological disturbances. Mice (N = 250) bred from
Per2Brdm1 heterozygotes were implanted subcutaneously with transponders and
released in approximately Mendelian ratios in four 400 m2 pens. An electronic
system stored the times of all visits to feeders of each individual. The study first
demonstrates that mice are not explicitly nocturnal in this natural environment.
Feeding activity was predominantly and sometimes exclusively diurnal and spread
nearly equally over day and night under the protective snow cover in winter. The
effect of Per2Brdm1 on activity timing is negligible compared to seasonal changes in
all genotypes. Second, the Per2Brdm1 allele did not have persistent negative effects
on fitness. In the first year, the allele gradually became less frequent by reducing
survival. New cohorts captured had the same Per2Brdm1 frequency as the survivors
from previous cohorts, consistent with an absence of an effect on reproduction. In
the second year, the allele recovered to about its initial frequency (0.54). These
changes in selective advantage were primarily due to female mice, as females lived
longer and the sex ratio dropped to about 25% males in the population. While it is
unknown which selective advantage led to the recovery, the results caution against
inferences from laboratory experiments on fitness consequences in the natural
environment. It also demonstrates that the activity of mice, while strictly nocturnal
in the laboratory, may be partially or completely diurnal in the field. The new
method allows assessment of natural selection on specific alleles on a day-today
basis.
U2 - 10.1177/0748730410397645
DO - 10.1177/0748730410397645
M3 - Article
SN - 0748-7304
VL - 26
SP - 118
EP - 129
JO - Journal of Biological Rhythms
JF - Journal of Biological Rhythms
IS - 2
ER -