Psychology 1100 Exam 2 Behavior Genetics 1 Why is this topic important for psychology a Genes only code for proteins not structures and functions i There is no fat ass gene ii Hoax Don t blame men for looking at other women its in iii Hoax parent child conflict is in the genes 2 Better understanding of misguided genetic deterministic notions a Gene for alcoholism not true i Provides genetic basis for development of bitter taste their genes receptors ii Alcohol tastes bitter so people with alcoholism in their genes shouldn t like it 3 Some basic genetic principles a Nucleus i Chromosomes are inside the nucleus ii The genetic material is stored inside the chromosomes iii 46 chromosomes per cell 23 from dad 23 from mom i Match up chromosomes into 23 pairs 1 from mom 1 from ii Match chromosomes by size centromere position band b Karyotype dad location c Human sex differences i 23rd position 1 Male XY 2 Female XX ii Most chromosomal abnormalities show up in pair 23 iii It is possible to be a genetic female and an anatomical male and vice versa d From chromosomes to the laws of inheritance i Alleles identical loci identical sites on a chromosome pair ii Gene pair 1 from dad 1 from mom iii Homozygous same proteins 1 2 dominant or 2 recessive 2 Dominant provides the basis for the normal trait 3 Recessive fails to provide a basis for the normal trait or may set up the basis for an abnormality iv Heterozygous different proteins 1 1 dominant and 1 recessive 2 Carrier of recessive gene and may pass it on to offspring v See page 45 of student manual e Laws of inheritance i Mendel ii Example PTC phenylthiocarbamide taste iii 70 of people taste the chemical as bitter iv 30 of people have not taste of PTC 1 Dominant 1 Recessive v See page 46 of student manual Chromosomal Abnormalities 1 Missing or extra chromosomes BAD 2 Amniocentesis a Week 15 20 b Diagnose chromosomal abnormalities c A needle is inserted into the amniotic fluid i Grow in tissue culture and do a karyotype 3 CVS Chronic Villus Sampling a Week 8 10 about a month earlier b Suck out tissue surrounding the amniotic sac and do a karyotype 4 23rd position except one 5 Down s Syndrome a Trisomy 21 i Occurs at 21st chromosome ii Extra chromosome at 21st position b Extra chromosome at 21st c Physical deficits d Severe retardation e New technique silence extra chromosome not yet available 6 Turner s Syndrome a Female 1 X chromosome at 23rd missing an X b Physical deficits i Webbed feet c Only specific intellectual deficits Intelligence not affected no retardation i ii The affected person is only bad at math and visual spatial organization 7 Females with Extra X chromosomes a 1 2 or 3 extra X s b 47 XXX 48 XXXX or 49 XXXXX i The more extra X s the more devastating the effects c Physical deficits d Severe retardation 8 Klinefelter s Syndrome a Male 2 X s and 1 Y at 23rd b Physical abnormalities c 75 have normal IQ 9 Fragile X Syndrome a Both sexes b Looks like the tip of the X chromosome will fall off c Leads to an overproduction of proteins d Asymptomatic carrier possibility i May pass on to offspring without showing symptoms ii Mental retardation and learning disorders iii Growth abnormalities 1 Large long head 2 Protruding ears 3 Large testicles iv Chimpanzees 1 Evolutionarily old a Found in chimpanzees unlike other syndromes The Nature Nurture Controversy 1 Genetics vs environment 2 Preformationism a Growth b Growth is important c Differentiation doesn t occur d Theory we are all preformed and only get bigger with time preformed fetus e Development of the microscope lead to observer bias people thought they were seeing preformed beings 3 Epigensis a Change b Differentiation c Change over time cell differentiation from conception The 2 Determinisms 1 Genetic Determinism a Genes code for developmental outcomes b Believe genes code for phenotypes they actually code for proteins c The Nominal Fallacy i Naming something doesn t explain it ii Labeling something genetic doesn t explain anything 1 Defies further explanation iii Example explain why all horses have a similar gait it s genetic 2 Environmental Determinism a Genes are not important b Example John Locke s tabula rasa c Believe genes aren t necessary they are provide a basis d Things that happen environmentally are significant e Calling something environmental is a nominal fallacy Interactionist View of Development 1 Problem 1 Alternativistic Thinking a Nature vs Nurture b Some behaviors are due to nature others are due to nurture i Depends on the behavior one or the other c Reality every behavior is a factor of both nature and nurture 2 Problem 2 Percentages a Some percentage of a behavior is due to genes the other percentage is due to environment not true b Reality a complex interaction of genes and environment can t be divided into percentages c Misapplication of population genetics Transactional View of Epigenesis 1 Complex view 2 Prenatal or postnatal 3 Something in the environment causes a gene to turn on causes neural development 4 What happens at one level affects all the other levels 5 See student manual A Metaphor for Behavioral Development 1 Pillsbury Doughboy Metaphor 2 Flour genes frying baking experience 3 Example 1 Flour salt water frying a Developmental outcome flour tortilla 4 Example 2 Flour salt water baking a Developmental outcome matzo 5 Example 3 Flour salt water yeast baking a Developmental outcome bread 6 Example 3 Flour salt water yeast cocoa baking a Developmental outcome brownie 7 Genes don t code for outcomes a Genes don t code for outcomes like flour doesn t 8 Developmental constraints a Can t take human genes and make a giraffe 9 Greater form is achieved as development proceeds a Epigenesis from undifferentiation to specificity 10 Cannot identify constituent elements by observing developmental outcome a Can t look at a flour tortilla and see flour b Can t look at an organism and identify everything that made it that way 11 Context dependency behavior a Changing where they develop grow up context causes a change in Domestication 1 Analogous Processes Darwin used to explain evolution a Natural Selection i Evolution nature acts on what will work ii Nature selects adaptive traits iii Slow changes b Artificial Selection i Domestication ii Humans select desired traits 1 Humans breed for desired trait organisms don t struggle to find successful traits 2 Desired traits usually have economic value iii Rapid changes 2 Definition of Domestication a Humans control