Biological bases of behavior and prenatal development Flashcards
genes
A group of nucleotide bases that provides a specific set of biochemical instructions.
chromosomes
Threadlike structures in the nucleus of the cell that contain genetic material.
alleles
A variation of a specific gene.
recessive traits
An allele whose instructions are ignored when it is combined with a dominant allele.
Dominant traits
The form of an allele whose chemical instructions are followed.
inherited disorders
-most carried by recessive alleles
genotype
A person’s hereditary makeup.
phenotype
The physical, behavioral, and psychological features that are the result of the interaction between one’s genes and the environment.
homozygous
When the alleles for a trait are the same.
heterozygous
When the alleles for a trait differ from each other
polygenic inheritance
When phenotypes are the result of the combined activity of many separate genes.
What is Down Syndrome’s genetic basis?
Extra genetic material on chromosome 21. It is not inherited, rather it occurs as a random event during cell division early in fetal development.
What is meant by incomplete dominance?
The situation in which one allele does not dominate another completely.
How does this relate to sickle-cell anemia?*
A disorder in which individuals show signs of mild anemia only when they are seriously deprived of oxygen; occurs in individuals who have one dominant allele for normal blood cells and one recessive sickle-cell allele
What is Phenylketonuria (PKU) and what is its cause?
- genetic disorder
- missing enzyme that converts amino acids into proteins…leading to accumulation in the body
- damages the nervous system
- causes mental retardation
How does changing the environment offset the negative consequences of PKU?
-diets that avoid amino-acids help prevent PKU and detect it early
Describe the findings of Caspi et al. (2003)’s study on the effects of polymorphism of the 5-HTT serotonin transporter and environmental variation on depressive symptoms
People that had the 5-HTT gene and were exposed to stressful life events had an increased chance of developing depression
Describe the findings of Caspi et al. (2002)’s study on the effects of child maltreatment and polymorphism on the MAOA gene on antisocial behavior.
Children low in MAOA gene had severe antisocial behaviors if they experienced maltreatment
What is the differential susceptibility model and what is the stress diathesis model?
Individuals vary in the degree they are affected by experiences or qualities of the environment they are exposed to. Some individuals are more susceptible to environmental influences than others ‐ not only to negative but also to positive ones
in what way do the predictions from these models differ and in what way they are the same?
- differential susceptibly model: fixed individual; plastic/malleable individual
- stress diathesis model: resilient individual, vulnerable individual
epigenetics
Study of heritable changes in gene expression that does not involve changes to DNA sequences
epigenetics examples of how it might affect behavior
-estrogen receptor expression promotes parental behavior
What is methylation and what do studies on cross-fostering tell us about its effects?
A process by which experience changes the expression of DNA—the genetic code is preserved but a gene is silenced by a methyl molecule
- Pups born to low maternal care mothers, and raised by high maternal care mothers: 1. have high estrogen receptor expression 2. Have high level of maternal care
- environment determines whether methylation is high or low, and if high then children are more prone to behavioral problems
What does heritability measure?
A measure of the extent to which heredity contributes to individual differences in a trait for a group of people
how is environment defined?
broadly
How are “twin” and “adoption” studies used to research the impact of genes and environment?
These studies indicate substantial influence of heredity in many areas, including intelligence, psychological disorders, and personality
