Life-Span Human Development, Ch. 2 Lecture PDF

Life-Span Human Development, 10e Chapter 2: Genes, Environment, and Development ©2022 Cengage Learning. All Rights Reserved. May no...

Life-Span Human Development, 10e Chapter 2: Genes, Environment, and Development ©2022 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 1  Individual Heredity ©2022 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 2  The Genetic Code Genetic coding stored on Chromosomes found in the nucleus − Chromosomes – threadlike structures made up of DNA (deoxyribonucleic acid) − 23 pairs of chromosomes in the nucleus of most human cells = 46  Cell division through mitosis  Genes, Chromosomes, and DNA − Exception – the sex cells - sperm, ovum – gametes – 23 unpaired chromosomes  Cell division through meiosis – from 1 to 4 cells  Fertilizition – 23 chromosomes from each parent combine to procreate  The 23rd pair of chromosomes determines biological sex, male determines sex of the baby XX = female; XY = male ©2022 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 3  And so it begins… Conception—when an egg is fertilized by a sperm Excellent Video on Fertilization ©2022 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 4  Table 2.2 Mitosis and Meiosis Compared Mitosis Meiosis in Males Meiosis in Females Begins Conception Puberty Early in prenatal period when unripened ova form Continues Throughout life span Throughout Throughout reproductive years; an adolescence and ovum ripens each month of the adulthood (can be menstrual cycle 16,40,70) Produces Two identical daughter Four sperm, each with One ovum (egg) and three cells, each with 46 23 chromosomes nonfunctional polar bodies, each chromosomes like its with 23 chromosomes parent Accomplishments Growth of human from Formation of male Formation of female reproductive fertilized egg, renewal reproductive cells cells of the body’s cells ©2022 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 5  Decoding the Genome Human Genome Project (2003): − Researchers mapped sequence of chemical units that make up the strands of DNA in a full set of 46 human chromosomes (23 from father and 23 from mothers). − Only about 2% of the human genome consists of what was defined as genes. − Other 98% play critical roles in regulating activity of the protein-producing genes – “on” and “off” precursors (some people have certain environments that trigger these, while others don’t, can explain differences between identical twins) ©2022 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 6  Variability through Reproduction Genes - segments of the chromosome code for specific protein production – 2 alleles (1 from mom; 1 from dad) Genotype to Phenotype − Genotype – actual genetic material So there are 3 possible combinations: Homozygous Dominant – CC  An allele can be dominant – C Heterozygous – Cc (doesn’t express)  An allele can be recessive – c Homozygous Recessive - cc − Phenotype – outward expression of the genotype  In Single Gene transmission these genotypes are associated with specific expression  Dominant transmission – Only need one dominant allele for expression  Recessive transmission – Need both alleles to be recessive for expression Heterozygous is considered a carrier but does not express  Partial expression – Sometimes both alleles express − Sex-Linked Characteristics ©2022 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 7  Let’s Do a Few Dominant Transmission (only need 1 dominant to express it in the phenotype) − Familial Hypercholesterolemia= HH (Homozygous dom) (pheno: have it) Hh (heterozygous)(have it) hh(Homozygous recessive) (Normal) Dad: hh x Mom Hh = Hh or hh (50% chance each) Dad:hh x Mom:HH = Hh or 100% chance Recessive Transmission (need both recessive alleles to express it in phenotype) − Cystic Fibrosis = CC (Homo dom.)(normal) Cc (normal/Carrier) (Heterozy) cc(cystic fibrosis) (homo recessive) − Mom: Cc x Dad: Cc = CC(25%), Cc(50%)= 75% normal , or cc (25% of having it) Partial Expression (Both alleles sometimes can express) − Sickle-cell Anemia SS (normal) , Ss (Partial/some sickle some normal) , ss (sickle cell) (U.S. National Library of Medicine) Sex Linked (much more common in males vs females) − Color-blindness ©2022 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 8  Polygenic Inheritance Polygenically Determined − Many – Most attributes are the result of multiple genes − These often show up as being normally distributed in the population − E.g. - Height, weight, and even IQ Gene-gene interaction – focus on the interdependence of two or more genes influencing characteristics, behavior, diseases, and development − Recent research – immune system functioning, cancer, and obesity ©2022 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 9  Mutations and Copy Number Variations Mutations - A change in the structure or arrangement of one or more genes that produces a new phenotype Odds that mutations will occur are increased by environmental hazards (age and higher risk of pregnancy) Most are just spontaneous errors during cell division. Fathers contribute about four times the number of new mutations as mothers. Copy Number Variations (CNVs) - Instances in which part of the genome is either deleted or duplicated More extensive than a mutation Can extend over a large stretch of DNA Can either be inherited or arise spontaneously Significantly increase the risks of a number of polygenic disorders involving the nervous system Another issue with expression of diseases and disorders ©2022 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 10  Other Issues in Genetics Wrong Number or Shape of Chromosomes − For example - Down’s Syndrome (extra chromosome) – Trisomy 21 − Sex-Linked Movie Trailer - Down's  XXY – Klinefelters  XO(1 x chromosome) – Turners  XYY  Fragile X syndrome (smaller x’s) ©2022 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 11  Genetic Diseases and Their Diagnosis Genetic counseling: − Provides information about nature, likelihood, effects, and treatment of genetically based diseases and disorders Carriers: − Do not have the disease but can transmit the gene for it to their children ©2022 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 12  Prenatal Diagnosis Prenatal detection of abnormalities (good to do if one or even both spouses are carriers): − Ultrasound − Amniocentesis (drawing out of amniotic fluid) − Chorionic villus sampling (sample of the chorian tissue to detect markers) − Maternal blood sampling − Preimplantation genetic diagnosis ©2022 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 13  Is Biology Destiny? No! Consider the case of PKU – Phenylketonuria − A single gene recessively transmitted metabolic disorder − Inability to metabolize phenylalanine − Build up results in seizures, cognitive impairment, mental disorders, early mortality − Test early – change diet, restrict phenylalanine – normal development But Genetics do play a role in helping to determine or shape development… ©2022 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 14  Studying Genetic and Environmental Influences ©2022 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 15  Studying Genetic and Environmental Influences Behavioral genetics: − Scientific study of the extent to which genetic and environmental differences among people are responsible for differences in personality or diseases − No longer nature vs nurture, it’s a mix of both; height is genetic, yet nutrition can also influence it Heritability: − Proportion of all the variability in the trait within a large sample of people that can be linked to genetic differences among those individuals ©2022 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 16 Behavioral genetics – field that examines influence of heredity and environment on individual differences Heritability - Proportion of all the variability in the trait within a large sample of people that can be linked to genetic differences among those individuals − Twin Studies  Compare similarity of identical (monozygotic) twins with fraternal (dizygotic) twins − Adoption Studies  Similarity of child with biological parents vs. adoptive parents  Compare adoptive siblings and biological siblings  Environment raised in vs genetic coding Concordance Rates – the % of cases where both in a pair has the Twins Segment attribute ©2022 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 17  Estimating Influences Contributions of three factors to individual differences: − Genes − Shared environmental experiences  Common experiences that work to make them similar; you vs brother: same parents, similar values − Nonshared environmental experiences  Experiences unique to the individual, not shared by others in family, different sports, clubs, friends ©2022 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 18  Correlations from a Twin Study of the Heritability of Angry Emotionality Raised Apart Identical twin pairs 0.37 0.33 Fraternal twin pairs 0.17 0.09 Pointing to specific correlations in this table, can you find evidence that genes, shared environment, and nonshared environment all contribute to individual differences in angry emotionality? ©2022 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 19  Molecular Genetics Molecular genetics: − Analysis of particular genes and their effects − Involves identification of specific variants of genes that influence particular traits − Can help identify the multiple genes that contribute to polygenic traits ©2022 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 20 Gene–Environment Interplay ©2022 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 21  Gene–Environment Interactions Possible Explanations Gene X Environment Interaction - effects of genes depend on what kind of Diathesis–stress model: environment we experience − Psychological disorder results from − How we respond to the environment an interaction of a person’s depends on what genes we have. predisposition or vulnerability to problems and the experience of Often is a combination of high-risk genes stressful events. and a high-risk environment to trigger psychological problems Differential susceptibility hypothesis: − Some people’s genes make them more reactive than other people to environmental influences, whether good or bad ones. ©2023 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 22  Gene–Environment Correlations Gene–Environment Correlations - Ways that a person’s genes and his or her environment are systematically interrelated Three types of gene–environment correlations: - Passive (same environment that was created by family member) - - Active (we get to choose/create our environment) Evocative (evoking things from environment based on genes) Behavioral geneticists are discovering that measures of environment are heritable. Genes influence how parents, peers, and others treat children. Environmental influences then contribute to the individual’s development. ©2022 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 23  Epigenetic Effects on Gene Expression Epigenetic Effects - Environmental factors affect whether or not particular genes in particular cells are expressed. − Might explain differences in identical twins ©2022 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 24  Table 2.7 Types of Gene-Environment Interplay Type Meaning Example Significance Gene–environment People with different genes Stress triggers depression Nature and nurture combine. Diathesis interaction are affected differently by only if a person has high- stress model of psychopathology. environmental influences. risk genes. Gene–environment People with different genes Children who have genes Nature affects nurture. Genetic correlation experience different associated with sociability predispositions influence experiences, environments— have sociable parents, which often strengthen genetically environments correlated with evoke sociable responses based tendencies. Measures of their genes. from others, and actively environment are not purely seek social interaction. environmental; they are genetically Influenced. Epigenetic effects Environment affects gene Early abuse/neglect results Nurture affects nature. Environmental expression through chemical in an overly reactive stress influences alter the functioning of codings on genes. response system and later genes; some epigenetic marks are psychological disorders. passed on to offspring. ©2022 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 25  Controversies Surrounding Genetic Research Gene therapy: − Involves substituting normal genes for the genes associated with a disease or disorder Developmentalists question the idea of trying to separate the influences of genes and environment on differences between individuals. ©2022 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 26