Background: PraderWilli syndrome (PWS) is a genetic disorder caused by the absence of expression of maternally imprinted genes on the long arm of chromosome 15 (15q 11-13). There are two main genetic sub-types: (1) deletion, caused by the absence of paternally derived genetic material; and (2) uniparental disomy (UPD), where two copies of…

The transition from first-generation to second-generation studies of genetic and environmental influences on the development of reading is underway. The first generation of quantitative genetic studies yielded an extraordinary conclusion: Fifty percent or more of the variance in most constructs, including reading, is attributable to genetic…

Linkage studies of complex phenotypes such as reading ability/disability (developmental dyslexia or reading disorder) and related componential processes, where the effects attributable to individual genes appear to be modest, are critically dependent on the nature and composition of the samples and the phenotypes analyzed. Thus, it might be…

Background: It has been proposed that some of the variability in reporting of associations between attention deficit hyperactivity disorder (ADHD) and candidate genes may result from mixing of genetically heterogeneous forms of ADHD using DSM-IV criteria. The goal of the current study is to test whether population-based ADHD subtypes defined by…

The expansion of newborn screening programs to include multiplex testing by tandem mass spectrometry requires understanding and close monitoring of performance metrics. This is not done consistently because of lack of defined targets, and interlaboratory comparison is almost nonexistent. Between July 2004 and April 2006 (N = 176,185 cases), the…

Two science questions are answered: (1) How can someone have one brown eye and one blue eye?, and (2) Why are magnets attracted to some metals, but not all metals? It is very rare that a human will have two irises of different colors. This condition, heterochromia, can be a normal variant or the result of an ocular disease. Heterochromia can…

For 25 years now, there has been a serious attempt to get at the fundamental cause(s) of dyslexia in our laboratory. A great deal of research has been carried out on the psychological and brain underpinnings of the linguistic dysfunctions seen in dyslexia, but attempts to get at its cause have been limited. Initially, observations were made on the…

Contemporary evolution biology has recognized the role of development in evolution. Evolutionarily oriented psychologists have similarly recognized the role that behavioral plasticity, particularly early in development, may have had on the evolution of species, harking back to the ideas of Baldwin (the Baldwin effect). Epigenetic theories of…

Although most discussions today start from the assumption that the secular rise in IQ must be environmental in origin, three reasons warrant giving the genetic phenomenon heterosis a closer look as a potential cause. First, it easily accounts for both the high heritability and low shared environmental effects seen in IQ, findings that are…

Epidemiological and clinical studies have consistently reported associations between smoking and posttraumatic stress disorder (PTSD). This study analyzed diagnostic interview data on 6,744 members of the Vietnam Era Twin Registry to clarify the PTSD-smoking relation and to examine whether genetic liability for smoking moderated this relation.…

This article analyzes the power of ambiguous metaphors to present scientific novelty. Its focus is a series of papers by the prominent population biologist W. D. Hamilton in which he redefined the meaning of biological altruism. In particular, the article draws on Kenneth Burke's dramatistic pentad to examine why suggestions of motive are so…

The cGMP-dependent protein kinase (PKG) has many cellular functions in vertebrates and insects that affect complex behaviors such as locomotion and foraging. The "foraging" ("for") gene encodes a PKG in "Drosophila melanogaster." Here, we demonstrate a function for the "for" gene in sensory responsiveness and nonassociative learning. Larvae of the…

To investigate whether motor skill learning depends on de novo protein synthesis, adult rats were trained in an acrobatic locomotor task (accelerating rotarod) for 7 d. Animals were systemically injected with cycloheximide (CHX, 0.5 mg/kg, i.p.) 1 h before sessions 1 and 2 or sessions 2 and 3. Control rats received vehicle injections before…

We previously reported that five repeated pulses of 5-HT lead to down-regulation of the TM-apCAM isoform at the surface of "Aplysia" sensory neurons (SNs). We here examined whether apCAM down-regulation is required for 5-HT-induced long-term facilitation. We also analyzed the role of the cytoplasmic and extracellular domains by overexpressing…

We present and discuss three examples of misapplication of the notion of conditional probability. In each example, we present the problem along with a published and/or well-known incorrect--but seemingly plausible--solution. We then give a careful treatment of the correct solution, in large part to show how careful application of basic probability…