Twin StudiesYou don’t know what the prenatal environment is likeMZ twins share chorion and blood supply (ie, more similar prenatal environment compared to DZ twins) so could be geneticsAdoption studiesA bad prenatal environment could reflect on poor childrenBiological children of low IQ or mentally ill parents tend to have similar problems even if raised by “great” adoptive parents could be genesAnother problem could be the multiplier effectGenes predispose you to behaviors and to different treatment by othersMultiplier effect (genes or prenatal influences)Increase tendency -> environment facilitates itWhat started out as potentially small effect of genes ends up having a high behavioral result… leading to an overestimation of heritabilityBlocks reuptake of dopamine, serotonin and norephinephrineBind to DAT blocking the reuptake of dopamineDopamine transporter (DAT): maintains proper dopamine levels by removing excess dopamine from synapseWhen there is a DRAMATIC INCREASE IN DOPAMINE in the synapse this is considered a “high”RitalineAlso blocks dopamine reuptake (same as cocaine)Different from cocaine becauseDoseOral admisinistration (longer to get to brain and blood plasma)Slow-release formulasMore gradual effect; no sudden “high”, withdrawal effects, or cravings, no crashTries to stimulate particular part of dopamine pathway to allow them to focusEctasyStimulant at low doses (increases in dopamine release and norepinephrine)At higher doses (recreational), also stimulates serotonin transporter) (Reverses serotonin transporterHallucinogenic effects, decrease in depression and anxietyHuman users; more depression, anxiety, sleep problems, memory deficits, attention problems, and impulsiveness, even 1-2 years after quitting.Ecstasy increases releases of posterior pituitary hormonesIncrease in Oxytocin releaseSocial attachment stuff (lovey dovey affect)Increase in Vasopressin releaseMore dangerous affect of ectasy – antidiuretic (stimulates you to drink water) can lead to water intoxication which can be fatal (because decreases sodium concentration in blood)Study Guide 2Lecture 1 - GeneticsWhat is heritability, how do we study it (what are twin and adoption studies…what do their results tell us?), and what are the problems with studying it?Estimate of how much of the variance in a characteristic (within a population) is due to differences in heredity (genes). Things like TV Watching, neuroticism, loneliness, and social attitudes are all heritable. Religion is the only thing that does not show heritability. Twin Studies- Identical twins are Monozygotic- Fraternal twins are dizygotic- The more DNA the twins share the more it’s high heritability - If there are less similar DNA there is low heritability- Resemblance: MZ > DZ à high heritability- Resemblance: MZ = DZ à low heritabilityAdoption Studies- IF adopted kids resemble biological parents more than adoptive parents, we assume high heritability - Virtual twinso Same environment, Different DNAProblems of heritability- Twin Studieso You don’t know what the prenatal environment is like o MZ twins share chorion and blood supply (ie, more similar prenatal environment compared to DZ twins) so could be genetics- Adoption studies o A bad prenatal environment could reflect on poor childreno Biological children of low IQ or mentally ill parents tend to have similar problems even if raised by “great” adoptive parents could be genesAnother problem could be the multiplier effect- Genes predispose you to behaviors and to different treatment by otherso Multiplier effect (genes or prenatal influences) Increase tendency -> environment facilitates it- What started out as potentially small effect of genes ends up having a highbehavioral result… leading to an overestimation of heritabilityWhat are examples of environmental influences on traits with otherwise high heritability?o Ex. Mice in elevated plus mazeo Ex. PKU - mental impairment due to genetic inability to metabolize a certain amino acid (phenylaenine)What is a sex-linked gene? Understand the heritability of sex-linked genes. The genes on the sex chromosomes (X and Y) it is mainly on the X, b/c it has lots more genes on it than the Y.- Consider a gene on the X chromosomeo If a male gets this gene, he will display the traito A female must get it on both of her X chromosomes to display the traito If a female has it on 1 X chromosome and not the other, she is a carrierWhat is a sex-limited gene? What are examples of each (sex-linked and sex-limited)?Sex-limited Genes are present in both sexes but has an effect only mainly in one sex. High levels of certain hormones affect certain genesAn example of a sex-linked gene is Fragile X Syndrome, red-green color blindness, Duchenne muscular dystrophy, and hemophilia.An example of a sex-limited gene is chest hair on men or breast on females.What is the multiplier effect? Another problem with estimating heritability: The multiplier effect- Genes predispose you to behaviors and to different treatment by otherso Multiplier effect (genes or prenatal influences) Increase tendency -> environment facilitates it- What started out as potentially small effect of genes ends up having a highbehavioral result… leading to an overestimation of heritabilityTerms to know and understand: DNA, RNA, gene, chromosome, transcription, translation, homozygous, heterozygous, dominant, recessive,- Transcription-from DNA to RNA- Translation-from RNA to proteins- Chromosome-contains DNA; we have 46 (22 paired and 2 sex chromosomes)o DNA (deoxyribonucleic acid)- in the nucleuso RNA (ribonucleic acid)-- Gene-sequence of DNA that contains information on hereditary characteristicso Homozygous-person with identical sets of genes on the 2 chromosomes (AA or aa)o Heterozygous-person with unmatched pair of genes on the 2 chromosomes (Aa)o Dominant-a gene that shows strong effect in heterozygous or homozygous condition (A)o Recessive-a gene that shows strong effect only in the homozygous condition (a)o Sex-linked genes-the genes on the sex chromosomes (X and Y) More commonly on the X chromosome because it is much larger Disorders more often occur in males because they only need the trait to display it while females require the trait onboth X chromosomes Examples : fragile X syndrome, red-green color blindness, hemophilia, muscular dystrophy- Sex-limited genes-present in both sexes but has an effect only (mostly) in one sexo Genes are
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