This article reports the findings of a study conducted to examine the types of information used by graduate students in the fields of biological and agricultural sciences at Iowa State University (ISU). The citations of doctoral dissertations submitted in nine agriculture and biological science subject fields (crop production and physiology;…

Several forms of eye movement dysfunction (EMD) are regarded as promising candidate endophenotypes of schizophrenia. Discrepancies in individual study results have led to inconsistent conclusions regarding particular aspects of EMD in relatives of schizophrenia patients. To quantitatively evaluate and compare the candidacy of smooth pursuit,…

In his 1979 "Human Development" article reprinted in this anniversary issue, James Wertsch presented an approach to genetic analysis of the shifting regulation of problem-solving behavior in early childhood. In my reflections on Wertsch's seminal contribution, I discuss ways that subsequent inquiry built upon ideas he elaborated in the…

What causes dyslexia, and how does it manifest across languages? As bilingualism becomes increasingly important globally, these questions have never been more critical--and this comprehensive volume from The Dyslexia Foundation explores them in unprecedented depth. Bringing together the best brain-based, genetics, and behavioral research in the…

Discusses the applicability and advantages of using yeasts as popular and ideal model systems for studying and understanding eukaryotic biology at the cellular and molecular levels. Cites experimental tractability and the cooperative tradition of the research community of yeast biologists as reasons for this success. (RT)

Various typs of DNA are discussed. Areas considered include highly repetitive and satellite sequences, genes encoding, ribosomal RNA, histone protein genes, and dispersed repeated genes that jump. Regulated genetic misbehavior, structure and use of unique genes, and higher order complexities of chromosomes are also discussed. (JN)

This module, for high school teachers, is the second of two modules about the Human Genome Project (HGP) produced by the Biological Sciences Curriculum Study (BSCS). The first section of this module provides background information for teachers about the structure and objectives of the HGP, aspects of the science and technology that underlie the…

Current research in plant genetics is described. Benefits of this research (which includes genetic engineering applications) will include reduction/elimination of crop diseases, assurance of genetic stability, and the creation of new crop varieties. (JN)

Carriers of fragile X mental retardation 1 ("FMR1") premutation alleles (55 to 200 CGG repeats) are generally spared the more serious neurodevelopmental problems associated with the full-mutation carriers (greater than 200 repeats) of fragile X syndrome. However, some adult male premutation carriers (55-200 repeats) develop a neurological syndrome…

Fragile X syndrome (FXS) is characterized by a pattern of morphological, functional, and molecular characteristics with, in at least some cases, apparent relationships among phenotypic features at different levels. Gross morphology differences in the sizes of some human brain regions are accompanied by fine structural alterations in the shapes and…

Near the end of his illustrious career, Gottlieb lamented the continued dominance of heritability analysis in human psychology and the difficulties in winning support for the developmental point of view. Recent, spectacular progress in molecular genetic neuroscience and the genetic study of behavior, however, is rendering heritability analysis…

In this contribution it is shown that Gilbert Gottlieb's theoretical contributions to developmental science, in particular his focus on individual development and his discussion of the limitations of developmental behavior genetics in this respect, are vindicated by recent theoretical developments in mathematical biology and psychometrics.

Basic quantitative genetic models of human behavioral variation have made clear that individual differences in behavior cannot be understood without acknowledging the importance of genetic influences. Yet these basic models estimate average, population-level genetic and environmental influences, obscuring differences that might exist within the…

A sample of Swahili-speaking probands with reading difficulties was identified from a large representative sample of 1,500 school children in the rural areas of Tanzania. Families of these probands (n = 88) were invited to participate in the study. The proband and his/her siblings received a battery of reading-related tasks and performance on…

Current neurocognitive theories of number processing [Dehaene, S., Piazza, M., Pinel, P., & Cohen, L. (2003). Three parietal circuits for number processing. "Cognitive Neuropsychology," 20, 487-506] state that mathematical performance is made possible by two functionally and anatomically distinct subsystems of number processing: a verbal system…