Authors
Biddle FG. Eden SA. Rossler JS. Eales BA.
Institution
Department of Medical Genetics, University of Calgary, Canada.
Title
Sex and death in the
mouse: genetically delayed reproduction and senescence.
Source
Genome. 40(2):229-35, 1997 Apr.
Abstract
A mammalian model of genetically postponed aging would be an important tool
to test not only different mechanisms of aging but also the
predictive value of various biomarkers of the aging process.
Under conventional conditions, the historical strains of
the laboratory mouse produce
their first litter between 9 and 13 weeks of age and have a
median time of death in their 2nd year. Our
POSCH-2 strain, which was derived from wild-caught Mus musculus domesticus,
produces its first litter in the current breeding
generations at approximately 47 weeks of age and continues to breed
throughout its 2nd and into its 3rd year of life. The aging
curve of POSCH-2 has not yet been determined for economic reasons. Late onset
of breeding is a characteristic of both females and males, but
sexual maturity is more reliably assessed in females.
The later breeding phenotype of POSCH-2 is genetically
recessive to early breeding of the C57BL/6J historical
laboratory strain and, since POSCH-2 females can be induced to ovulate at 8
weeks of age (but pregnancy does not result), the signal
rather than the ovarian receptor to ovulate
may be delayed. The genetically delayed reproduction and
potentially longer life of the POSCH-2 strain appears to be
a new trait in the mouse.
The strain may be a useful mammalian model for aging studies
and for the evaluation of antagonistic pleiotropy as a
genetic model for the evolution of aging.