The definition of inbred strains of animals is provided, underscoring
the homogeneity of the individuals in a strain, as well as the lack of
allelic variation within each individual. Inbred animals present long
-term reproducibility and relative stability, which facilitates experi
mentation over a long period of time. The derivations of several speci
fic groups of inbred animals including coisogenic, congenic, and recom
binant inbred lines are detailed. Applications for inbred strains to t
he study of aging including analysis of longevity characteristics, gen
es involved in the control of age-related parameters and gene interact
ions with other genes or the environment are presented. The concept of
aging as a consequence of genes and the ramifications of competitive
pleiotropy are discussed. The distinction between aging and age-relate
d diseases or lesions is explored. Cumulative lesion incidence is sugg
ested as a biomarker of aging. Copyright (C) 1997 Elsevier Science Inc
.