The Influence of Parental Age on the Genetic Quality of the Progeny of Mice II: Certain Parameters of Fertility and the Ratio of Sexes in Successive Generations

Abstract

The following fertility parameters were investigated: number of fertile pairs, size of first litter, length of the period from initial mating at three months old to the production of the first litter and the duration of puberty in the progeny (determined as the time between birth and production of tho first litter). In the young (Y), control (C) and old (O) lines, the parents were mated in successive generations at 1, 3 and 8 - 14 months old, respectively. The results obtained indicate that parental age influenced the size of tho progeny's first litter and tho length of their puberty. In the old line, a decrease occurred in the size of litters in successive generations, and for their progeny -- an increase in the number of days between birth and production of tho first litter. The ratio of sexes in the progeny was determined at the age of 3 weeks and a significant dominance of males in the young and control lines was found.