Wild and domesticated Atlantic salmon males display large variation for sea age at sexual maturation, which varies between 1-5 years. Previous studies have uncovered a genetic predisposition for variation of age at maturity with moderate heritability, thus suggesting a polygenic or complex nature of this trait. The aim of this study was to identify associated genetic loci, genes and ultimately ...

the aim followed in the present research was to investigate the effect of nine generations of divergent selection on some reproductive and egg production traits in japanese quail. the results indicated that selection for 4-week body weight, increased the age at sexual maturity of hw and of lw lines, in comparison with control, for about 7 and 3 days, respectively (p

The Tanner-Whitehouse method to predict adult stature uses current stature, current skeletal age (SA), and chronological age (CA), and, if available, change (gain) in stature and SA over the previous year. Since assessment of SA requires invasive techniques, a method is proposed to predict adult stature noninvasively and to use percentage of adult stature as a maturity indicator. Age-specific m...

INTEREST in the genetic effects of irradiation on quantitative characters usually takes the form of two questions. Does irradiation effect a genetic change in the mean of quantitative characters such as human intelligence? Does irradiation induce genetic variance in quantitative characters that could be utilized by the plant or animal breeder for genetic improvement? Experimental data relevant ...

Life history traits of wild animals can be strongly influenced, both phenotypically and evolutionarily, by hunting and fishing. However, few studies have quantified fishery selection over long time periods. We used 57 years of catch and escapement data to document the magnitude of and trends in gillnet selection on age and size at maturity of a commercially and biologically important sockeye sa...

Despite the widespread assumption that paternal investment is substantial in our species, previous studies have shown mixed results in relation to the impact of fathers on both offspring survival and reproductive outcomes. Using data from a large representative sample of British men, we tested whether father absence is associated with the timing of reproduction-related events among boys, while ...

The timing of early life-history events, such as sexual maturation and first reproduction, can greatly influence variation in individual fitness. In this study, we analysed possible sources of variation underlying different measures of age at social and physical maturation in wild baboons in the Amboseli basin, Kenya. The Amboseli baboons are a natural population primarily comprised of yellow b...

Variation in mean food availability, and in the variance around the mean, affects the growth rate during development. Previous theoretical work on the influence of environmental quality or growth rates on the phenotypic traits age and size at maturation assumed that there is no variation in growth rate or food availability within a generation. We develop a stochastic dynamic programming (SDP) m...

GERMANO, D.J. 1994. Growth and age at maturity of North American tortoises in relation to regional climates. Can. J. Zool. 72: 918-931. North American tortoises (Gopherus spp.) are long-lived species that occur in a variety of habitats. I described growth of tortoises using Richards' growth model based on measures of scute annuli. Gopherus flavomarginatus is the largest species and grows the fa...

The testicular growth of guinea-fowls in relation to age was compared under 3 constant photoperiods (7L: 17D; 14L: 10D; 20L: 4D) from 3 weeks of age. Although long daylength (14L or 20L) caused precocious development of the gonads, it also limited total adult gonadal weight to around 1 800 +/- 200 mg. Short daylengths (7L) delayed the development of the gonads but their adult weight was enhance...