CHAPTER 3

Vocabulary flashcards related to biological factors influencing criminal behavior.

Behavior genetics

The study of how genetic and environmental factors influence individual differences in behavior. Aims to determine the extent to which our actions are due to inherited genes versus environmental influences.

Molecular genetics

A branch of biology focused on the structure and function of genes at the molecular level. In criminology, it identifies specific genes that may predispose individuals to certain behaviors, particularly antisocial behaviors, and how these genes are transmitted across generations.

Dizygotic (DZ) twins

Also known as fraternal twins, resulting from two separate eggs fertilized by two different sperm. They share about 50% of their genes, similar to non-twin siblings, and can be of different sexes.

Monozygotic (MZ) twins

Identical twins that originate from a single fertilized egg that divides into two, sharing 100% of their genes. Always of the same sex, they are genetically identical.

Shared environments

Environmental conditions and experiences shared by both twins, such as being raised by the same parents and living in the same home. These environments tend to promote similarity in traits and behaviors.

Nonshared environments

Distinct experiences and environmental factors unique to each twin, such as different friends or participation in different activities. These contribute to differences between twins.

Concordance

The degree to which related individuals (e.g., twins) both exhibit a specific trait or behavior.

Twins' Early Development Study (TEDS)

A large-scale UK-based longitudinal study examining behavioral problems and development in twins from early childhood through adolescence, aiming to disentangle genetic and environmental influences on development.

Environmental Risk (E-Risk) Longitudinal Twin Study

A study that examines the interplay between genetic predispositions and environmental risk factors in the development of antisocial behavior, using MZ and DZ twins. It investigates how genetic vulnerabilities interact with adverse environments.

Twin Study of Child and Adolescent Development (TCHAD)

A longitudinal study using the Swedish Twin Registry to investigate the development of aggression and delinquency in children and adolescents. It assesses parental reports of aggression and the children’s delinquent behavior to study genetic and environmental influences.

Index subjects

The primary individuals of interest in a research study, often those exhibiting a specific behavior or condition that is being studied.

Monoamine oxidase A (MAOA) gene

A gene that regulates the metabolism of several neurotransmitters, including serotonin, dopamine, and norepinephrine, all of which play a role in mood, behavior, and aggression regulation.

MAOA-L gene

A variant of the MAOA gene, characterized by lower enzymatic activity. This low-activity form is associated with increased aggression and violence, particularly in individuals who experienced maltreatment during childhood. It affects neurotransmitter metabolism, potentially leading to altered mood and increased aggressive tendencies.