Recently, Lenski et al \cite{Elena,Lenski,Travisano} have carried out several experiments on bacterial evolution. Their findings support the theory of punctuated equilibrium in biological evolution. They have further quantified the relative contributions of adaptation, chance and history to bacterial evolution. In this Brief Report, we show that a modified M-trait Bak-Sneppen model can explain ...

In the classic view introduced by R. A. Fisher, a quantitative trait is encoded by many loci with small, additive effects. Recent advances in quantitative trait loci mapping have begun to elucidate the genetic architectures underlying vast numbers of phenotypes across diverse taxa, producing observations that sometimes contrast with Fisher's blueprint. Despite these considerable empirical effor...

Eleven goat breeds of different origin (10 Spanish and 1 African) were considered for this study: Zambian Dwarf, Azpi-Gorri, Blanca-Andaluza, Blanca-Celtibérica, Blanca de Rasquera, Catalana, Malagueña, Moncaína, Murciano-Granadina, Negra Serrana and Pyrenean. Nine linear body measurements for females, as well as the body weight ratio between gender and body weight, were obtained from literatur...

A locus is a position on a chromosome occupied by genes that determine the state of a particular phenotypic character. When that phenotypic character is something that is measurable, such as mm of fat, or kg of body weight, rather than something that is qualitative, such as eye or coat colour, the locus will be referred to as a quantitative trait locus (QTL). The various occupants of the locus ...

SoyBase, the USDA-ARS soybean genetic database, is a comprehensive repository for professionally curated genetics, genomics and related data resources for soybean. SoyBase contains the most current genetic, physical and genomic sequence maps integrated with qualitative and quantitative traits. The quantitative trait loci (QTL) represent more than 18 years of QTL mapping of more than 90 unique t...

The linkages of achievement-related boredom with students’ appraisals and performance outcomes were examined in a series of 5 exploratory, cross-sectional, and predictive investigations. Studies 1 and 2 assessed students’ boredom in a single achievement episode (i.e., state achievement boredom); Studies 3, 4, and 5 focused on their habitual boredom (i.e., trait achievement boredom). Samples con...

Biologists have long strived to understand what causes phenotypic differences between two individuals. This includes differences in morphology, disease susceptibility, physiology as well as potential metabolic differences underlying these higher order phenotypes. The diversity between individuals is partitioned into both environmental and genetic variation. Most genetic variation studied to dat...

The concept of the mutation component of a genetic trait is discussed and its relation to heritability investigated. It is found that for qualitative traits held in the population by opposing directional selection and mutation, the mutation component equals the broad sense heritability. The mutational component of a quantitative trait with an intermediate optimum is found generally to be betwee...