CRISPR-cas technology is being incorporated into undergraduate biology curriculum through lab experiences to immerse students in modern technology that is rapidly changing the landscape of science, medicine and agriculture. We developed and implemented an educational module that introduces students to CRISPR-cas technology in a Genetic course and…

School genetics is changing. Nowadays, students are more likely to be introduced to the idea that many characteristics of organisms, including those of humans, are not determined by the actions of just one or two genes but result from interactions between the products of many genes and the environments of each organism. This article asks whether…

Genetic and epigenetic differences exist within monozygote twin-pairs and might be especially important in the expression of autism. Assuming phenotypic differences between monozygotic twins are due to environmental influences may lead to mistaken conclusions regarding the relative genetic and environmental contribution to autism risk.

Epigenetics is emerging as one of the most dynamic and vibrant biomedical areas. Multiple lines of evidence confirm that inherited genetic changes alone cannot fully explain all phenotypic characteristics of live organisms, and additional factors, which are not encoded in the DNA sequence, are involved. The contribution of non-genetic factors is…

In the development of genetic theories of Autistic Spectrum Disorder (ASD) various characteristics of monozygotic (MZ) and dizygotic (DZ) twins are often considered. This paper sets forth a possible refinement in the interpretation of the MZ twin concordance percentages for ASD underlying such genetic theories, and, drawing the consequences from…

The phenotypic and etiologic relation between internalizing and autistic-like traits is studied using a community-based twin sample. Internalizing and autistic-like traits showed moderate phenotypic overlap but have specific genetic influences.

Burt (2009) recently published a meta-analysis of twin studies on behaviors associated with childhood psychopathologies, concluding that the finding that traits associated with attention-deficit/hyperactivity disorder (ADHD) were the only behaviors that did not show a significant influence of shared environment (C) was surprising. We agree,…

Using a genetic design of 234 six-year-old twins, this study examined (a) the contribution of genes and environment to social versus physical aggression, and (b) whether the correlation between social and physical aggression can be explained by similar genetic or environmental factors or by a directional link between the phenotypes. For social…

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…

To test the hypothesis that the etiology of reading difficulties may differ for males and females in more severely impaired samples, reading performance data from monozygotic (MZ), same-sex dizygotic (DZ[subscript ss]), and opposite-sex dizygotic (DZ[subscript os]) twin pairs were analyzed using a model-fitting implementation of the DeFries-Fulker…

Attention-Deficit/Hyperactivity Disorder (ADHD) is a neurobiological disorder that is characterized by developmentally inappropriate levels of inattention, impulsivity, and hyperactivity. Between 3% and 7% of school-aged children are affected by ADHD. ADHD is a lifespan condition that affects children, adolescents and adults of all ages. It…

Insecure mental representations of attachment, a nearly invariant feature of cluster B personality disorders, have never previously been studied in twins. We conducted the Adult Attachment Interview (AAI) on 33 pairs of monozygotic (MZ) female twins reared together as an initial exploration of causal influences on mental representations of…

Genetic and environmental influences on prereading skills in preschool and on early reading and spelling development at the end of kindergarten were compared among samples of identical and fraternal twins from the U.S. (Colorado), Australia, and Scandinavia. Mean comparisons revealed significantly lower preschool print knowledge in Scandinavia,…

Prereading and early reading skills of preschool twin children in Australia, Scandinavia and the United States were explored in a genetically sensitive design (max. N=627 preschool pairs and 422 kindergarten pairs). Analyses indicated a strong genetic influence on preschool phonological awareness, rapid naming and verbal memory. Print awareness,…

The first case study of identical male twins concordant for DSM-IV Asperger's disorder (ASD) was presented. Their monozygocity was confirmed by short tandem repeat analyses with a probability of 99.999963%. Despite sharing the same DNA and environment, the twins are different in comorbidity (i.e., major depressive disorder in the elder and absence…