Presents insights into the endosymbiotic theory based on a re-examination of evidence from investigations into the archaebacteria and other strange organisms inhabiting the hindguts of wood-eating insects. Examines the mechanism of evolutionary change and the speed with which it occurs. (RT)

Described is a simple technique for isolating DNA from halophilic bacteria. Materials, procedure, and additional experiments are outlined. It is stated that the DNA obtained will be somewhat contaminated with cellular proteins and RNA. Offers a procedure for greater purification. (RT)

Described is an activity in which students are able to determine that DNA can be transferred between bacteria and should be able to predict the type of DNA transferred. Methods, materials, and results are discussed. (CW)

Contends that the natural science curriculum does not prepare biology students for understanding the process of evolution. Proposes improved teaching approaches related to geological time, the natural transition of earth environments, the variability and alteration of genetic makeup, and the biological potential of species as being necessary for…

Research for biological-genetic markers of alcoholism is discussed in context of a multifactorial, heterogeneous, developmental model. Suggested that strategies used in linkage and association studies will require modification. Also suggested several extant associations of genetic markers represent true secondary interactive phenomena that alter…

Presents activities that use the learning cycle to engage students in meaningful inquiries in the study of Mendelian genetics. Includes content-related background and teaching tips for each phase of the learning cycle. (JRH)

Presents an activity that aims at enabling students to recognize that DNA and RNA are information molecules whose function is to store, copy, and make available the information in biological systems, without feeling overwhelmed by the specialized vocabulary and the minutia of the central dogma. (JRH)

Caregivers of 55 boys with fragile X syndrome (ages 3-12) and 57 matched controls completed five behavioral questionnaires. Principal components analysis yielded 5 behavioral clusters: abnormal language, tactile defensiveness, poor self-control, poor eye contact/shyness, and hand flapping. Boys with fragile X were four times more likely to have…

Clinical features, pathogenetic hypotheses, and symptoms of the cardio-auditory or surdo-cardiac disorder first reported by Jervell and Lange-Nielsen are described, and methods of diagnosis and treatment are presented, to alert teachers and other professionals to potentially life-threatening symptoms they may observe when working with deaf and…

This paper considers key properties of behavioral phenotypes of mental retardation syndromes, including within-syndrome variability and between-syndrome similarities and qualitative differences. The "new genetics" research requires combining data from three strategies: (1) a psychiatric approach, (2) psychometric methods, and (3) syndrome-specific…

Estimates the extent to which heredity influences perceptions of childhood family environment in a sample of 58 monozygotic and 46 dizygotic pairs of adult twins who were reared apart. The data confirm the importance of genetic factors in some, but not all, measures of family environment. Environmental influences were more important than genetic…

The mother, father, and adolescent siblings from 675 families were observed interacting in problem-solving sessions. Siblings were monozygotic twins, dyzygotic twins, or full siblings in nondivorced families and full, half, and unrelated siblings in stepfamilies. Results suggested a greater genetic component to adolescent behavior than to parent…

Pedigree analysis of 12 young adults (9 of whom had learning disabilities) indicated that learning disability (LD) was strongly familial but that the type of disability (reading or math) was not directly inherited. Autoimmune disorders were significantly correlated with LD. In seven of the LD families, adults failed to overcome earlier reading and…

Suggests that experiential canalization is appropriately applied to constraints caused by the behavior of an organism or members of its species. When other aspects of the environment propel the organism to develop in certain ways, this process reflects adaptation to the environment. Conditions for evolution of experience as a guide to development…

This study provides support for a potential subclinical marker in the executive function domain of siblings (n=18, ages 8-18) of autistic individuals, compared to learning-disabled controls. No group differences in theory-of-mind abilities were found. The need to develop more sensitive measures is discussed. (Author/JDD)