Explores longitudinal data on sex, height and weight differences among pubescent monozygotic and dizygotic twins for theoretical implications related to heredity-environment interaction effects. (RH)

Three models of behavioral effects of genetic disorders characterized by mental retardation were compared: (1) no-specific effect model (all genetic disorders have identical behavioral outcomes); (2) totally specific model (each genetic disorder has unique outcomes); and (3) partially specific model (two or more genetic disorders share outcomes…

ApoE gene polymorphism was examined in 100 adults with Down syndrome with and without dementia (Alzheimer's disease) and 346 control subjects. Additionally, a meta analysis of studies (total N=480 subjects) was performed. Results indicated a similar incidence of the gene across groups but subjects with the allele tended to an earlier onset of…

Describes how to use various types of licorice ropes to illustrate the similarities between RNA and DNA. Specifically addresses illustrations of replication, transcription, protein synthesis, mitosis, meiosis, mutations, and anomalies. (DDR)

Selective abortion of fetuses with Down syndrome is discussed in terms of abortion perspectives, genetic testing, legislation, and ethical principles. The ethical principles of autonomy, beneficence, nonmaleficence, fidelity, and justice are offered as guidelines for the examination of legal standards imposed by legislation. (Author/PB)

Evidence for the genetic basis of autism is offered, as is evidence that environmental determinants also play a role. Research involving the Human Genome Project, using linkage analysis with affected autistic sibling pairs to identify polymorphic marker genes, is described and proposed. (DB)

Suggests that computer science analogies can aid the understanding of gene expression, including the storage of genetic information on chromosomes. Presents a matrix of biology and computer science concepts. (DDR)

Explains the use of genetic algorithms to combine results from multiple query evaluations to improve relevance in information retrieval. Discusses niching techniques, relevance feedback techniques, and evolution heuristics, and compares retrieval results obtained by both genetic multiple query evaluation and classical single query evaluation…

Examines the influence of apolipoprotein E gene states on three cognitive outcomes in 173 people at age 11 and in the same people at age 77 and examined the change in IQ between these ages. There was no significant main effect of gene status on IQ in youth or old age, nor in cognitive change across the lifespan. (SLD)

Describes a sophisticated version of the fruit fly experiment for teaching concepts about genetics to biology students. Provides students with the opportunity to work with live animals over an extended period. (JRH)

For pairs of full siblings, half-siblings, and cousins, analyzed maternal ratings of children's behavior problems at three times between ages 4 and 10. Found that nonshared environmental influences were substantial at each age but did not contribute to continuities in children's problem behaviors. Results favor a liability model that relates…

Discusses strategies to duplicate current research protocols using biochemical methods of analysis. Describes the use of the Silver Sequence kit that provides a technically simple and relatively inexpensive DNA sequencing exercise. (JRH)

Used a genetic design to investigate association between physical aggression and language development in 19-month-old twins. Found a modest but significant correlation between aggression and expressive vocabulary. Substantial heritability was found for physical aggression. Quantitative genetic modeling suggested that the correlation could not be…

Presents three biographical sketches of scientists including John Wesley Powell (first to explore the geology of the Grand Canyon), Joseph von Fraunhofer (his work in optics led to the science of spectroscopy), and Gregor Mendel (of Mendelian genetics fame). Other scientists are mentioned along with sources for additional biographical information.…

Findings from a study in which twins were given tests of onward repetition and auditory processing are discussed. Children with specific language impairments were impaired on both measures, but deficits had different origins. Auditory processing problems showed no evidence of genetic influence, whereas the nonword repetition deficit was highly…