I.
Multifactorial Traits
Chapter 7 (pp. 137-154)
Genes and the Environment Mold most Traits
a. Polygenic Trait-activities of more than one gene not necessarily equal
b. Multifactorial Trait-influence by the environment as well as genetics
Can a polygenic trait also be multifactorial?__YES______
c. A multifactorial trait is is continuously varying only if it is also __polygenic______________
d. 3 Examples of Multifactorial Traits
i. Fingerprints_______________________
1. Genes
2. Prenatal Development Weeks 6-13
ii. _Height___________________________
1. Genes
2. Diet
iii. __Eye Color________________________
1. Explain in your own words Figure 7.4-5 Eye colors in Humans come from 2 genes with 2
alleles each, creates a bell curve because midrange colors have more combns. of alleles
e. _Skin Color-____
i. Explain in your own words Figure 7.5-_A model of 3 genes with 2 alleles each contribute to skin
color. Midrange colors have more possible combinations leading to a bell curve.___
II.
5 Methods of Investigating Multifactorial Traits
a. __Empiric Risk_____i. How? predictions of recurrence based on the trait’s incidence in a specific population
b. __Heritability___i. How?___ The percentage of the phenotypic variation for a particular trait that is due to genes in a
certain population at a certain time._
c. ___Adopted Individuals_i. How? Used to study the environmental influence due to similar environments but not similar genes
d. ___Twins___i. How? Identical genes and Concordance- the percentage of twins in which both express a trait_
ii. MZ Twins- Monozygotic (Identical)
iii. DZ Twins- Dizygotic (Fraternal)
e. __Association Studies______i. How? Looks for traits that may be linked_____________________
ii. SNP Mapping-_Single Nucleotide polymorphism- single base sites that differ among individuals.
…track large populations for SNPs
III.
Some Multifactorial Traits
a. _Heart Health____
b. _Body Weight____
i. Leptin-A protein hormone that fat cells secrete when eating that suppresses appetite and increases
metabolism
c. Fingerprint Patterns
d. Height
e. Eye Color
f.
Skin Color
g. Hair Color
I.
Genetics of Behavior
Chapter 8 (pp155-170)
Genes contribute to most Behavioral Traits
a. 1 in _1,000______individuals is affected by behavior disorders.
b. Behavioral disorders are commonly affected by__Genes___and __Environment_______.
c. In your own words, explain how behavior is connected with genetics. __Genes control the distribution of
neurotransmitters which are the chemical messengers that connect nerve cells __
II.
Eating Disorders
a. _15___-__21__% of individuals with anorexia die from the disorder. Highest of any psychiatric disorder
III.
Sleep
a. Narcolepsy-_daytime sleepiness and a tendency to fall asleep very rapidly, several times a day_____
b. Cataplexy-_short episodes of muscle weakness leading to collapse ___
IV.
Intelligence
a. (Environment or Genetics) have a greater influence on IQ
b. Why do genetic contributions to intelligence become more prominent with age?
____People become more able to control their environment so genes become more apparent_________
V.
Drug Addiction
a. Tolerance-_the need to take more drugs to achieve the same effects__________________
b. Dependance-__the onset of withdrawal symptoms what a person ceases taking the drug___
VI.
Mood Disorders
a. MDD-__major depressive disorder –lethargic, sad, no longer enjoys certain activities_______
b. Bipolar Disorder-___depression alternates with mania (hyperactive, restless and excited)___
VII.
Schizophrenia- (blue box pg.166) _a debilitating loss of the ability to organize thoughts and perceptions which
leads to withdrawal from reality___
a. Environmental or Genetic (Explain)-_both environmental factors can increase the risk of developing the
condition (the flu during second trimester of pregnancy)_________
b. Environmental risk factors- 1.___Maternal malnutrition__________2._Borna virus__________ 3._oxygen
deprivation____________4._Obsteric or birth complication_5.___Psycoactive drug use (PCP)__
6.__Traumatic brain injury_7.__Herpes infection at time of birth____