FINAL EXAM CHAP 18 Flashcards
What is a behavior?
a reaction to internal or external stimuli that alerts an organism’s response to its environment
- can be innate or learned
What must be defined to study behavior?
Behavioral phenotypes
what is single gene trait?
with a dominant or recessive pattern of inheritance
How does the nervous system help with the focus of behavior genetics?
The nervous system receives and processes stimuli like simple reflex reaction, senses, memory, and innate/learned behaviors
T or F: many disorders with a behavioral component are associated with alterations in the structure and/or function of the nervous system
True
What are nerve cells (neurons)?
One of the cell types in the CNS
What are dendrites?
they receive nerve impulses
What are axons?
sends nerve impulse to other neurons
How do synapses interconnect cells in the nervous system?
Synapses are the functional connection between neurons. Nerve impulses travel from the pre synaptic neuron to the post synaptic neuron. Neurotransmitters in the pre synaptic neuron transmit the impulse across the synaptic cleft
How can neurotransmitters affect our behavior?
It can affect our mood, memory, and our sense of well-being. Variations in the timing of neurotransmitter activity can affect behavior.
T or F: Normal brain function depends on normal synaptic behavior
True
How does single gene mutations cause behavioral disorders?
Mutations in the MAOA gene cause disruption to normal synaptic function.
What is Huntington’s disease?
It is an adult-onset neurodegenerative disorder, autosomal dominant.
What causes Huntington’s disease?
Caused by the accumulation of misfolded proteins in the brain. The more trinucleotide repeats, the more severe the symptoms are. Less than 34 (doesn’t have HD)
How does HD affect brain degeneration?
It damages the striatum and cerebral cortex in HD brains
How are animal models used to search for behavior genes?
Transgenic mouse models have been used to investigate the biological/genetic mechanisms that underlie
- alcoholism
- schizophrenia
- bipolar disorder
- Alzheimer’s disease
- Parkinson’s disease
- ALS
How do mice develop symptoms similar to the conditions of humans?
SOD1 mutations cause ALS symptoms in mice so they’re put into the mice.
Mouse models of HD
Transgenic mice carried various numbers of trinucleotide repeats . Brains of HD mice show cell death in the striatum and cerebrum.
What are the genetics of complex behavioral disorders?
Caused by a combination of diff factors. Genes and environmental factors affect behavioral phenotypes.
How is schizophrenia a complex behavioral disorder?
Caused by many genes along with environmental triggers
How is genetic component of human traits studied in twins?
Differences between MZ (identical) twins due to environment only. Differences between DZ (fraternal) twins due to genetic and environment factors.
T or f: the increased risk associated with increased genetic relatedness suggests a genetic component to schizophrenia
True
What are the genetic links shared among psychiatric disorders?
Many psychiatric disorders share alleles, SNPs, and other variant
How does schizophrenia and autism disorders have similar variant on chromosome 16?
Duplications are associated with schizophrenia and deletion is associate with ASD.
ZNF652 gene
Increased methylation in individuals with schizophrenia
Decreased methylation in individuals with BPD
How does social behavior affect genetics?
AD and addiction
What is Alzheimer’s disease?
A progressive, fatal, neurodegenerative disorder. It begins with memory loss, dementia, disturbances in motor activity, and recognition. Brain lesions form because of accumulation of amyloid beta-protein
What are the two forms of AD?
Familial (early onset) and sporadic (late onset)
What environmental factors affect AD?
Exposure to pollution, exercise, diet, smoking, infections, location
How is there a genetic component to alcoholism?
Allele variants of genes involved in alcohol metabolism are associated with alcoholism (ADH & ALDH)
behavioral trait is caused by 2 genes, one that has a large affect and one that has a small affect. This is a ____ trait.
polygenic
T/F: Huntington’s disease is caused by an amino acid substitution
False
T/F: most behavioral traits are controlled by a single gene
False
which of the following is a single gene disorder?
Huntington’s disease
What are some multi gene disorder?
Schizophrenia, Alzheimer’s disease, alcoholism
alleles at the HTT gene, with more than ___ CAG repeat will cause Huntington’s disease
more than 34 (40)
A concordance of less than 100% the greater than 0% indicates that:
there is an environmental component to a treat/disease
T/F: GWAS can identify genetic variants, like SNPs, that may be affecting a trait
True
A mutant Huntington’s proteins in conjunction with the ____ protein causes neuron degeneration in the stratum and cerebral cortex of the brain.
Rhes
which kind of twins share 50% of their alleles?
Dizygotic
Alzheimer’s disease is associated with ______ the protein amyloid beta
an accumulation of
if stimulant addiction has a heritability of 0.4 and alcohol addiction has a heritability of 0.55, which disorder is more controlled by genetics
alcohol addiction
if opiate addiction has a heritability of 0.6, what proportion of the trait is controlled by the environment?
0.4
Poly genetic trait:
multiple genes control trait
Complex trait:
many genes all have small effects and the environment affects the trait
