PRE 305 1st Edition Lecture 4 Outline of Last Lecture I Research Methods A What is research B The scientific method C Elements of research D Methods of data collection E Types of research designs F Research Ethics Outline of Current Lecture I Nature and nurture A Gene environment interactions B Genetic disorders C Behavioral genetics Current Lecture Gene environment interactions Parent Child Genotype biological parents pass genes onto children 1 Genetic inheritance one copy of chromosomes from mother and one from father Father determines the sex chromosome 2 Genotype 23 pairs of chromosomes that a person has 3 Phenotype physical expression of genes hair color height etc Dominant genes trait that will be evident if one or more copies is inherited Brown eyes brown hair etc Recessive trait will be evident only if two copies of the recessive gene are inherited Blue eyes red hair etc Parents will have a recessive trait that they don t know of Parents have brown hair child has red hair Genetic disorders Single gene disorders can be caused by mutations or by inheriting two copies of a recessive gene Tay Sachs PKU cystic fibrosis Chromosome disorders too may or two few of a specific chromosome or breakage of a chromosome Down syndrome Fragile X syndrome Disorders with an unidentified genetic basis genes play a role but no single gene or chromosome determines Autism schizophrenia depression alcoholism Genetic disorders and the X chromosome males are more susceptible to genetic disorders arising from genes on the X chromosome because they only have one X chromosome hemophilia red green colorblindness Behavioral genetics Examining the role of genetics and environment in producing behavior Adoption studies look at biological siblings raised in different environments Twin studies look at behavioral similarities to see the influence of genetic inheritance 1 Monozygotic identical and dizygotic fraternal twins