title: Analysis of inheritance of growth trajectories in laboratory populations of guppy-fish.
abstract: We analysed the variation of growth trajectories for body length from 40 to 90 days of age in three laboratory populations of Poecilia reticulata. The populations used were two lines of guppy-fish obtained by artificial selection for increased and decreased body length at 70 days and one line maintained under free-breeding condition. The factor analysis performed on the phenotypic correlation matrices among age-specific values of body length showed that a very large portion of the phenotypic variation is confined to a single factor. This factor corresponds to a simultaneous increase/decrease at all ages, hence representing the variation in the height of the growth trajectories. A smaller portion of the variation describes an increase/decrease at early ages followed by the reverse in the later ages, which corresponds to the variation in the shape of the trajectories. The genetic analysis performed on the height and shape of the growth curves showed a additive genetic component for the height in the free-breeding population and for the shape in the selected lines.
authors.affiliation: Dipartimento di Biologia Evoluzionistica e Sperimentale, Università di Bologna, Italia.
authors.forename: G
authors.initials: G
authors.lastname: Rocchetta
authors.forename: M L
authors.initials: ML
authors.lastname: Vanelli
authors.forename: C
authors.initials: C
authors.lastname: Pancaldi
mesh_terms: D000818:Animals; D001824:Body Constitution / Q000235:genetics; D001947:Breeding; D005260:Female; D008297:Male; D010641:Phenotype; D011036:Poecilia / Q000235:genetics* / Q000254:growth & development*