Human Behavior Part 2 Molecular Genetics Epigenetic movie will be on test LOOK IT UP BG behavioral genetics illustrates the three main points about phenotypes 1 Shared environment little influence 2 Nonshared influential 3 Heritability strong genetic component Which genetic components are influential for certain phenotypes Which certain genes are related for causing differences in people BG cannot give that answer but a different research design can Molecular Genetics Basic info about genes Approximately 25 000 genes in the human body When the Human Genome Project began we were expecting 100 000s of thousands of genes but no there are only 25 000 Genes are stretches of DNA that work together to perform specialized functions DNA A chemical code that allows us to form develop and function live Stored in the nucleus of every cell except red blood cells Info encoded into DNA partially determines every observable and unobservable characteristics People vary because their DNA varies Every person has their own unique sequence of DNA Exceptions Monozygotic twins Each person s arrangement of genes is known as s genotype The expression of a genotype is a phenotype but there are variances due to things like dominant and recessive genes Two fibers twisted around each other to form a double helix Each fiber is referred to as a polynucleotide Along the backbone of each polynucleotide is a sequence of nucleotides also Structure of DNA called bases DNA Four different types of bases A T C G Those letters make up the genetic alphabet and depending on how they arranged will make someone different Base pairs are held together with chemical bonds Chemical bonds hold the two strands of DNA together and there is a specific bonding pattern A T G C T A C G The ordering of the base pairs is very important You will get very different results in terms of phenotypes if the base pairs vary in ordering Differences in genotypes will cause significant differences in phenotypes Humans share about 99 9 of their DNA About 0 1 of DNA is responsible for many of the changes among the human population Distinguishing DNA We can use that phrase when we talk about any 2 people Base pairs working together are called genes In reality genes are made up of 1 000 or more base pairs What do genes do They code for the production of protein Proteins are essential to life 1 Structural Proteins Hair nails tendons ECT 2 Functional Protein Coordinate actions and activities of the body 2 18 13 Molecule Genetics Genes and the environment Nature and nurture Combined to create different behaviors and different personality traits It helps answer the question as to why people with the same genetic material turn out differenty Because of the combination of nurture and nature also referred to as gene environment interplay Two main types of gene environment interplay 1 Gene X environment interactions GxE 2 Gene X environment correlations rGE GxE Genetic effects are only visible or highly visible in certain environment Conversely environmental effects are most potent given the presences of certain phenotypes Two people in the same environment may interpret it and react to it differently because of their unique genotypes Can explain why children in the same family turn out differently Every sperm that fertilizes an egg carries a different genetic material except for monozygotic twins Can also explain why rehabilitation effort works for some people but not for others because of their genotypes interacting with that program Remember Caspi et al s article They found that the certain gene only had an effect in certain environment Classic example of GxE A growing body of empirical evidence has revealed the importance of GxEs in the etiology of crime and delinquency rGE We often see that an environment is related to a person s behaviors or their We think that the environment caused this association the environment was there personality traits before the child was born Ex An intelligent child who is always reading and engaging in stimulating cognitive stimulation The SSSM would say that if you place a child in a room of books or have your fetus listen to Mozart it would boost your child s IQ which is bullshit BUT IQ and cognitive ability are heritable traits and then just having the good environment for that isn t enough Intelligent parents are more likely to have intelligent children Assortative mating increases this possibility Intelligent parents also more likely to have books and other cognitive stimuli in the home The environment reflects their genetic propensities abilities Other examples are plentiful Musical ability mechanical abilities athletic abilities ECT Refers to the close association between the genes and the environment There are 3 types of rGE 1 Passive Things like IQ and sports gene Children receive 2 elements from parents genetic and environment It s received passably The child has no influence or say of the genetics that they get OR the environment that they grow up in The environment is largely a reflection of their parents genetic propensities Individuals play an active role in seeking out environment that are compatible with their genetic tendencies Engage in niche picking you go to areas or activities that you like where you can find other people who also like that stuff 2 Active 3 Evocative People elicit certain responses from their environment based in large part on their genotype Two people will elicit two different responses from the same environment For example if someone gets mad easily you would tweak your behavior to not make them mad If someone is a negative person you won t call them as much 2 20 13 Molecular Genetics Which genes may relate to ASB Genes responsible for the production transportation and breaking down of neurotransmitters are the most promising Neurotransmitters Chemical messengers that allow for communication between neurons Sends electric signals across a neuron Billions of neurons in the brain meaning that there are thousands of connections for each neuron They travel over the gap to send messages It beings with an action potential LOOK UP HOW NEUROTRANSMITTERS WORKS They send messages across the synaptic gap and then they need be mopped up taken away to allow effiency for future crossings Occurs in two ways 1 Some of them are recycled reuptake process called Transporter Proteins 2 Some of them are degraded by an enzyme such as MAOA If problems with either processes that could result with problems
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