Chapter TwoHeredity and Environment

Learning Objectives

After reading Chapter 2, students will know:

where in our cells genetic instructions are located, and how these instructions are encoded in our DNA.

how we inherit traits from our parents, and how those traits are expressed.

how environmental forces modify genetic instructions.

the kinds of disorders that are caused by problems in how genes are inherited.

techniques available to help individuals deal with genetic disorders.

why the study of behavior genetics is important in helping us understand gene–environment interactions.

why adopted children and twins are of special interest to those who study behavior genetics.

how environmental events exert their influence on developmental processes.

how one’s family and culture help shape the way that development unfolds.

COPYRIGHT © 2013, 2010, 2007 BY PEARSON EDUCATION, INC., UPPER SADDLE RIVER, NJ 07458.  ALL RIGHTS RESERVED.

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COPYRIGHT © 2013, 2010, 2007 BY PEARSON EDUCATION, INC., UPPER SADDLE RIVER, NJ 07458.  ALL RIGHTS RESERVED.

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Key Terms and Concepts

Age cohortAllelesApplied Behavior Analysis (ABA)AutosomesBaseBase pairsBehavior geneticsCellsChromosomeCodominanceCongenital anomaliesDeoxyribonucleic acid (DNA)Developmental nicheDominantEpigeneticsEthnocentrismGametesGene imprintingGene therapyGenesGenetic counselingGenotypeHabituationHeritabilityHeterozygousHomozygousIncomplete dominanceKaryotypeMeiosisMitosisMutationNonnormative influencesNormative age graded influencesNormative history graded influencesNucleotidesPartial schedulesPhenotypePhobiaPolygenic inheritanceProteinsPunishmentRecessiveRecombinant DNA technologyReinforcer

Self conceptSelf efficacySex chromosomesSex linked traitsShaping

COPYRIGHT © 2013, 2010, 2007 BY PEARSON EDUCATION, INC., UPPER SADDLE RIVER, NJ 07458.  ALL RIGHTS RESERVED.

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Chapter Outline

I. Molecular Genetics

A. Human cells 1. CELLS – the smallest self contained structures in the human body

2. Cell membrane allows nutrients and other chemicals to enter and waste products to exit the cell

3. Cytoplasm is the fluid that plays host to specialized structures

4. Mitochondria are the powerhouses of the cell

5. Endoplasmic reticulum, golgi apparatus, and ribosomes are involved in the production of proteins

6. DEOXYRIBONUCLEIC ACID – a large, complex macromolecule composed of carbon, hydrogen, oxygen, nitrogen, and phosphorus that contains the genetic code that regulates the functioning and development of an organism

B. DNA

1. Shaped like a double helix or twisted ladder

2. NUCLEOTIDES – the building blocks of DNA

3. BASE – a nitrogen-carbon-hydrogen component of nucleotides

a. adenine

b. thymine

c. cytosine

d. guanine

4. BASE PAIRS – a rung in the DNA ladder; the base adenine pairs only with the base thymine, the base cytosine pairs only with the base guanine

5. Three things specify differences:

a. the overall number of base pairs in the DNA molecule is very large.

b. different species and different members within a species have different numbers of base pairs.

c. the order in which the base pairs occur is important.

6. Only 0.1% of human DNA varies from person to person

7. Race-based markers do not appear to exist in the human genome

C. Genes

1. GENES – the basic units of inheritance that are composed of sequences of base pairs within the DNA of an organism. Human are estimated to have between 20,000 and 25,000 genes

D. Protein Synthesis

1. PROTEINS – molecules that perform a diverse array of crucial functions in the human body

2. The process of protein synthesis consists of a complex series of reactions from which hundreds of thousands of different proteins can be constructed

II. Chromosomes, Genes, and Cell Division * CHROMOSOME – a chain of genes visible under a microscope; humans normally have 46 chromosomes

* AUTOSOMES – in humans, consists of 22 of the 23 pairs of chromosomes, except those that determine sex

*SEX CHROMOSOME – in humans, the 23rd chromosome pair, which determines sex. Exist in two forms: X and Y.

*KARYOTYPE – a photograph of a cell’s chromosomes arranged in pairs according to size

A. Cell division and reproduction 1. MITOSIS – the process of ordinary cell division that results in two

cells identical to the parent cell

2. MEIOSIS – the process of cell division that yields sperm and ova, each including one half of a full set of chromosomes

3. GAMETES – reproductive cells that are formed by the process of meiosis

4. In males, meiosis occurs in the testes

5. In females, meiosis occurs in the ovaries

B. From genotype to phenotype

1. ALLELES – a pair of genes found on corresponding chromosomes that affect the same trait

2. GENOTYPES – the genetic code of a given individual

3. Simple dominance and recessiveness

a. DOMINANT – in genetics, one gene of a gene pair that will cause a particular trait to be expressed

b. RECESSIVE – in genetics, one of a gene pair that determines a trait in an individual only if the other member of that pair is also recessive

c. PHENOTYPE – in genetics, those traits that are expressed in the individual

d. HOMOZYGOUS – the arrangement in which the two alleles for a simple dominant recessive trait are the same

e. HETEROZYGOUS – the arrangement in which the two alleles for a simple dominant recessive trait differ

4. Combinations of genes

a. POLYGENIC INHERITANCE – the inheritance of a trait that is determined by multiple genes

b. INCOMPLETE DOMINANCE – the case in which a heterozygous genotype results in a phenotype that is intermediate between the phenotypes of dominant versus recessive homozygous genotypes (e.g., sickle cell anemia)

c. CODOMINANCE – the case in which both dominant and recessive alleles are expressed in the phenotype (e.g., AB blood type)

5. SEX LINKED TRAITS – traits that are determined by genes on the 23rd chromosome pair

C. The variation of traits among individuals

1. Meiosis and individual variation

a. Individual variations occurs in several ways

b. When chromosomes separate at the beginning of meiotic division, genetic material randomly crosses over resulting in new recombinant alleles

c. Chance determines which half of the chromosome pairs will go into which sperm or ovum. This is called independent assortment.

d. Which sperm and ovum unite is also determined by chance

2. Mutation

a. MUTATION – an alteration in the DNA that typically occurs during mitosis or meiosis and is therefore transmitted to subsequent cells through cell division

b. In mitosis, if a viable mutation occurs early in development, it will be passed along to all the cells replicated

c. In meiosis, a mutation is incorporated into the genetic code and passed along to offspring in the sperm or ova

D. Gene–Environment Interactions: The study of epigenetics

1. Genetics (nature) and environment (nurture) are in constant dynamic interaction with each other. These interactions occur at many levels.

2. EPIGENETICS: nongenetic factors that influence how genes are expressed

III. Genetic disorders *CONGENITAL ANOMOLIES – also called birth defects; abnormalities that result from genetic and chromosomal problems as well as from exposure to toxins, disease, and such during the prenatal period. Approximately 3% of babies born each year have one.

A. Sex linked disorders

1. Occur via dominant-recessive genetic patterns. Such conditions will be seen more commonly in men (e.g., hemophilia, pattern baldness)

2. Sex linked disorders also occur when the gametes do not replicate correctly

3. Chromosomal breakage can also occur; this breakage produces brain deficiencies. Seen in both males and females

4. Fragile X syndrome leads to a form of mental retardation that has become the most common hereditary disorder associated with intellectual disability

B. Autosomal disorders

1. Occur when the other 22 pairs of chromosomes have defects

2. Down syndrome (trisomy 21) is the most common autosomal disorder, and the second leading inherited cause of intellectual disability

3. GENE IMPRINTING – a phenomenon in which gene expression and phenotype depend on which parent the genes come from

4. Gene imprinting can cause problems if one parent’s genes are defective

C. Mitochondrial disorders

1. Mitochondria are small structures in cells that convert food to energy. If they have defective DNA, it can cause a genetic disorder

2. Most often due to mutations, not inheritance, so only one family member will be affected.

D. Genetic counseling

1. GENETIC COUNSELING – a widely available resource that can help potential parents evaluate genetic risk factors in childbearing

Activity 2a

Activity 2b

Article 2a, 2b, 2c

Lecture 2b, 2d

and enable them to make choices that reflect their values and circumstances

2. Often includes the analysis of parental medical records and family histories to construct a genetic pedigree which identifies previous instances of congenital anomalies

3. If it reveals the presence of a heritable genetic disorder, the counselor evaluates the couple’s risk of having a baby with the disorder

E. Advances in genetic research and treatment 1. RECOMBINANT DNA TECHNOLOGY – an assortment of highly

sophisticated procedures in which DNA is extracted from cell nuclei and cut into segments; the resulting fragments are then joined to self replicating elements, in essence forming functional gene clones, these are then placed in host bacterial cells to be maintained and cultured

2. GENE THERAPY – an approach to establishing cures for genetic disorders that can be applied at any point from altering the molecular structure of DNA to altering the process of protein synthesis. Involves reinserting genetically altered cells into the person from whom they were harvested

3. Retroviruses are viruses capable of penetrating cells but they do not have adverse effects

IV. Behavior genetics *BEHAVIOR GENETICS – the study of the relationship between behavior and genetic makeup

*HERITABILITY – the extent to which a trait is inherited verses acquired, thus presuming a genetic basis; note that heritability estimates are influenced by the environments in which they are considered

A. Adoption and twin studies

1. Studies how individuals who are more-or-less genetically related develop

2. This allows us to understand the relative importance of genetic and environmental determinants of behavior

3. Both twin and adoption studies suggest that genetics and environment both play important roles

4. A large meta-analysis concludes that 41% of human behavior is genetically influenced.

5. Special care has to be taken when interpreting results because the degree of environmental effects needs to be considered

Activity 2c, 2d

WebVid 2a, 2b

Lecture 2c

Article 2d, 2e

V. Environmental influences and contexts

A. Basic processes that affect behavior

1. HABITUATION – ceasing to attend or respond to repetitive stimulation; occurs at several levels, from sensation to perception to higher cognition

2. Classical conditioning

a. The kind of learning that occurs when one stimulus is associated with another through repeated trials

b. PHOBIA – the unreasonable fear of an object or a situation 3. Operant conditioning

a. REINFORCER – a stimulus that increases the likelihood that the behavior the reinforcer follows will recur

b. PUNISHMENT – a stimulus that decreases the likelihood that the behavior the punishment follows will recur

c. PARTIAL SCHEDULES – a procedure in which only some responses are reinforced or punished; produces much stronger habits that continuous reinforcement

d. SHAPING – systematically reinforcing successive approximations to a desired behavior

B. Applied Behavior Analysis (ABA)

1. Simple learning processes underlie many basic habits

2. APPLIED BEHAVIOR ANALYSIS – also called behavior modification; a method that uses conditioning procedures to change behavior

C. Social learning and the evolving self concept 1. SELF CONCEPT – one’s beliefs and feelings about oneself;

defines who an individual is

2. SELF EFFICACY – what a person believes he or she is capable of doing in a given situation

VI. Environment in a broader context: family and culture *DEVELOPMENTAL NICHE – the interaction of components that determines the unique world of each individual. Includes physical & social settings, child rearing customs, and the overall psychology of the caregiver.

A. Family systems

1. The way family interacts with each other, especially when children are young, has an intricate and dynamic impact on development

2. Members of the same family do not necessarily experience the same environment. There is also a set of nonshared experiences and relationships

3. The birth of a second child complicates things

a. The mother spends less time with the first child

b. For the first born, an affectionate relationship with the father tends to become closer

c. Conflict with the mother increases for the first born

B. The family as transmitter of culture

1. In complex multiethnic societies, the embedding of culture in children is more difficult

2. The cultural traditions of an ethnic minority family may be in conflict with the majority

3. ETHNOCENTRISM – the tendency to assume that our own beliefs, perceptions, customs, and values are correct or normal and that those of others are inferior or abnormal

4. Socialization is a lifelong process through which individuals are taught to function as members of a social group

C. Sociocultural influences on development across the lifespan

1. AGE COHORT – group of individuals of similar ages

2. NORMATIVE AGE GRADED INFLUENCES - the biological and social changes that normally happen at predictable ages (e.g., puberty, starting school)

3. NORMATIVE HISTORY GRADED INFLUENCES – the historical events that affect large numbers of individuals at the same time(e.g., wars, epidemics)

4. NONNORMATIVE INFLUENCES – the individual environmental factors that do not occur at any predictable time in a person’s life (e.g., divorce, illnesses)

5. Mediating factors – the impact of normative & nonnormative influences often varies according to:

a. Age

b. Gender

c. Ethnicity

6. Human development: an interactive process

a. Different backgrounds, different motivations, and different interests need to be considered when thinking about development

Lecture 2a

b. It is important to consider the ways in which hereditary and environmental factors that interact to produce the uniqueness of each individual

Lecture Suggestions

Lecture 2a. History and its Influence

When discussing the difficulties of developmental research in the context of history-graded and age-graded, many of the students in an undergraduate class have difficulty understanding how much the world has changed in the last 100 years. I find it useful to present a series of findings about how health care, life expectancy, etc. have changed over time and how these changes make it difficult to study many seemingly straightforward development issues (e.g., does memory get worse as we age, how do the schools of today compare to those of 30 years ago). The American History website sponsored by Kingwood College (http://kclibrary.lonestar.edu/decades.html) provides a very nice list of cultural events by decade for the United States. The CDC website with the Center for Statistics (http://www.cdc.gov/nchs/fastats/) provides very useful statistical information about a number of important health issues. For example, the average life expectancy in 1900 in the US was 47.3 years while in 2007 it was 77.9 years.

Lecture 2b. Genetic Counseling

Develop a lecture on the pros and cons of genetic counseling. Genetic counseling is a widely available resource according to the text that can aid potential parents in evaluating the genetic risk factors in childbearing and provide information that can help them make informed decisions. It is important to provide the students with information regarding the information that can be gleaned from this process. This involves providing information about the analysis of family histories as well as the use of prenatal testing. The options available to the potential parents, such as deciding to adopt if the risk of genetic problems is high given family history, should be discussed. The options available to parents if genetic problems are identified through the use of prenatal tests can challenge the parent’s value systems.

Questions to be discussed can include: What prenatal tests should be routine? What are the justifiable factors for terminating a pregnancy? What role should insurance companies play in the decision process and in determining the factors that may be considered for terminating a pregnancy? In a broader scope, who should have a say in determining whether parents can terminate a pregnancy?

It may be useful to tell the class some examples of reproductive rights manipulations in the U.S. For example, eugenics programs that resulted in the sterilization of the

mentally retarded were legal up through the 1960’s. See information available at http://en.wikipedia.org/wiki/Compulsory_sterilization.

Lecture 2c. Genetic Treatments, Genetic Engineering, and Cloning

The potential for the availability of genetic treatments has raised a number of interesting ethical and practical questions. Although genetic treatments and cloning are still primarily in the development stages, they hold great promise if certain technical obstacles can be overcome. There is a good section in the Craig textbook on these procedures. The use of genetic engineering, primarily in the form of selective breeding, to modify the characteristics of organisms in agriculture has been practiced for decades. The use of these procedures in humans has sparked much debate and the passage of some laws, even though the technology remains limited. The use of cloning technology to produce organs for transplants or to treat diseases such as Parkinson’s could potentially alleviate the suffering of large numbers of people. Recent movies (e.g., The Island and The 6th Day) have examined the issues of cloning. See these websites for more information.

http://www.bionetonline.org/English/Content/sc_leg1.htmhttp://www.cbc.ca/news/background/genetics_reproduction/cloning.html

Lecture 2d. Fertility: When and How to Make it Happen

There are many misconceptions about fertility. Develop a lecture examining the biology underlying successfully getting pregnant and reproduction or the myths associated with sex and pregnancy (Richmond et al., 2001). Topics can include: 1) how easy is it to get pregnant; 2) can you increase your odds of having a boy or a girl; and 3) infertility. For example, most students know that fertility rates decrease with age. However, recent research suggests that the decrease may begin earlier than previously thought. This is interesting because more and more women are delaying child rearing until later ages. The combination is resulting in a higher rate of infertility as couples try to build a family.

See these websites and articles:http://www.babyplan.org/uk/fertWindow.asphttp://www.chem-tox.com/infertility/

Richmond, D.M., Sabatini, M.M., Krueger, H.L., & Rudy, S.J. (2001). Contraception: Myths, facts, and methods. Dermatology Nursing, 13, 19-26.

Class Activities

Activity 2a. Magazine/Newspaper Survey

Ask students to search through recent issues of magazines and newspapers for articles on genetic research. Students can locate the original research report in order to

determine how accurately the magazine or newspaper reported the story. Students can present their results either in a written paper and/or a presentation to the class.

Activity 2b. Living with Down Syndrome & other Developmental Disorders

Ask students to investigate how individuals and families are affected by developmental disorders, such as Fragile X syndrome, Down syndrome, Williams syndrome, etc. Students can make presentations to the class about what life is like for a child born with one of the syndromes described in the chapter. It is likely that some of your students will know individuals with some of these syndromes. The students may be able to share anecdotes about these individuals.

Activity 2c. Genetic Counseling

Arrange for a professional genetic counselor to visit the class and to explain how couples planning a family are provided with information about genetics and assessed for potential disorders occurring in their offspring. Alternatively, students can consider whether information gained through genetic counseling should be made available to the government and health insurance companies using Handout 2-1. Students can be instructed to interview 3 other people outside of class using this handout and can discuss the various responses in small groups in the next class.

Activity 2d. Critical Thinking Journals

Imagine you and your partner received information from a genetic counselor that a certain type of birth defect was possible for your children. For example, the counselor estimates that odds are your child has a 10% chance of having a mild birth defect (i.e., one that would cause little hindrance to the child in their quality of life). What would you do? What preparations or decisions would you make? What options would you want available to you? Now do the same thing with a moderate (i.e., one that would cause an impairment in the child’s quality of life that could be handled with additional resources and time) and severe birth defect (i.e., one that would cause a major decrease in the child’s quality of life).

Internet Video Clips

WebVid 2a. Time: 3:31

Description of different types of genetic testing:http://www.youtube.com/watch?v=dJuo937gz44 (Genetic Counseling)

WebVid 2b. Time: 9:02

BBC documentary on Designer Babies with commentary by Princeton professor Lee Silver:

http://www.youtube.com/watch?v=TN9ep4B9Hw0&feature=PlayList&p=C7E239A945F4C4BA&playnext=1&playnext_from=PL&index=56 (Designer Babies)

Supplemental Readings: Current Research

Article 2a. Amso, D., Casey, B. J. (2006). Beyond What Develops When. Current Directions in

Psychological Science, 15, 24–29.

One major contribution of neuroscience to understanding cognitive development has been in demonstrating that biology is not destiny that is, demonstrating the remarkable role of experience in shaping the mind, brain, and body. Only rarely has neuroscience provided wholly new insights into cognitive development, but often it has provided evidence of mechanisms by which observations of developmental psychologists could be explained. Behavioral findings have often remained controversial until an underlying biological mechanism for them was offered. Neuroscience has demonstrated promise for detecting cognitive problems before they are behaviorally observable and, hence, promise for early intervention. In this article, we discuss examples drawn from imitation and mirror neurons, phenylketonuria (PKU) and prefrontal dopamine, maternal touch and stress reactivity, and nongenetic (behavioral) intergenerational transmission of biological characteristic.

Article 2b. Bellugi, U., Doyle, T. F., Järvinen-Pasley, A., Korenberg, J. R., Reilly, J., Reiss, A. L.

(2007). Affect, Social Behavior, and the Brain in Williams Syndrome. Current Directions in Psychological Science, 16, 99–104.

Williams syndrome (WS) is a rare genetic disorder characterized by intellectual impairment and a distinctive physical and neuropsychological profile. Relative to their level of intellectual functioning, individuals with WS exhibit strengths in language and face recognition, with deficits in visual-spatial cognition. A heightened appetitive drive toward social interaction is a strong behavioral feature. Relative to other neurodevelopmental disorders, WS has a clearly defined genetic basis, together with a consistent neurocognitive profile of strengths and deficits. Thus, this disorder offers unique opportunities for elucidating gene-brain-behavior relationships. We focus on manifestations of the unusual social profile in WS, by examining data within and across levels of cognition, brain, and molecular genetics.

Article 2c. Widaman, K. F. (2009). Phenylketonuria in Children and Mothers: Genes,

Environments, Behavior. Current Directions in Psychological Science, 18, 48–52.

Phenylketonuria (PKU) is an inborn metabolic error in which metabolism of phenylalanine into tyrosine is disrupted. If the diet of an infant with PKU is not restricted, blood phenylalanine levels are elevated, leading to irremediable brain damage and severe mental retardation. Children with PKU who are placed early and continuously on a low-phenylalanine diet develop normal levels of intelligence, and brain damage is largely prevented. However, if the diet of a mother with PKU is unrestricted during her pregnancy, high phenylalanine levels in her blood can cross the placental barrier and damage the developing fetus in multiple ways. These results demonstrate how genes and environmental factors combine to create prenatal environments that can have profound effects on the growth and development of offspring during infancy and childhood.

Article 2d .

Johnson, W. (2010). Understanding the genetics of intelligence: Can height help? Can corn oil? Current Directions in Psychological Science, 19, 177–182.

Although the subject is controversial, identifying the specific genes that contribute to general cognitive ability (GCA) has seemed to have good prospects, at least among psychological traits. GCA is reliably and validly measured and strongly heritable, and it shows genetically mediated physiological associations and developmental stability. To date, however, results have been disappointing. Human height shows these measurement characteristics even more strongly than GCA, yet data have indicated that no individual gene has more than trivial effects and this is also true for corn oil. The potential for environmental trigger of genetic expression, long recognized in evolutionary and developmental genetics, as applied to these seemingly disparate traits, can help us to understand the apparent contradiction between the heritability of intelligence and other psychological traits and the difficulty of identifying specific genetic effects.

Article 2e .

Johnson, W., Turkheimer, E., Gottesman, I. I., & Bouchard, T. J., Jr. (2009). Beyond heritability: Twin studies in behavioral research. Current Directions in Psychological Science,18, 217–220.

The heritability of human behavioral traits is now well established, due in large measure to classical twin studies. We see little need for further studies of the heritability of individual traits in behavioral science, but the twin study is far from having outlived its usefulness. The existence of pervasive familial influences on behavior means that selection bias is always a concern in any study of the causal effects of environmental circumstances. Twin samples continue to provide new opportunities to identify causal effects with appropriate genetic and shared environmental controls. We discuss environmental studies of discordant twin pairs and twin studies of genetic and environmental transactions in this context.

Handout 2-1Interview on Genetic Counseling

Select 3 people you know and ask them the following questions. Be sure to describe each person interviewed as follows:

Sex ____ Age ____ Education (highest level completed) _____________

Occupation ______________________

______________________________________________________________________

1. Do you think everyone should be required to have genetic counseling before having a baby? Why or why not?

2. If genetic counseling indicates that a couple has a chance of having a baby with a genetic disorder, should be the couple be allowed to have a baby? Why or why not?

3. If a couple has a baby after being warned that they have a 25% or greater chance of having a child with a serious genetic disorder, should they be able to use public health services for the child? Why or why not?

4. Do you think that health insurance companies and life insurance companies should be allowed to treat individuals with high probability of developing a genetic disorder differently than those without such a chance, such as charging them more for coverage or dropping them altogether as clients? Why or why not?

5. Do you believe that an individual’s genetic profile should be off-limits to companies? Should it be off-limits to the government? Why or why not?

Multimedia Resources

MyDevelopmentLab – MULTIMEDIA RESOURCESThese web-based expansions on topics allow instructors and students to watch a video clip, explore a topic, or simulate an experiment. The in-text multimedia is not exhaustive—there are many more resources available to instructors and students on-line at www.MyDevelopmentLab.com.

Molecular GeneticsCategory Title Description Duration PageAnimation DNA Molecules N/A 37

Chromosomes, Genes, and Cell DivisionCategory Title Description Duration Page

Watch Twins Separated at Birth, Reunited

Good Morning America 2007 interviews identical twins who were separated at birth. The twins were given up for adoption by their mother, who suffered from mental illness, and were placed in separate homes as part of a twin study to determine the relative influence of nature versus nurture. Neither twin knew she had a twin sister until they were reunited as adults. The interview provides an opportunity to raise ethical concerns associated with some types of psychological research. 42

WatchGenetic Predisposition to Alcoholism

Psychiatrist Dr. Marc Schuckit of the San Diego Veterans Affairs Medical Center reports on his research findings that a low response to alcohol as a young adult is a powerful predictor of alcoholism. 43

WatchThe Big Picture: Genes, Evolution, and Human Behavior

In this video, the history of the nature versus nurture debate is introduced and explained in a way that helps viewers understand why there is cause for disagreement and what scientists are currently trying to determine about nature versus nurture. 43

Watch Special Topics: Epigenetics: A Revolutionary Science

In this video, we learned about epigenetics and how strong an influence the environment can be on our genetic development, gene

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expression, and behavior.

Genetic DisordersCategory Title Description Duration Page

Watch Down Syndrome

This vignette focuses on an interview with a young adult with Down Syndrome (Tim) and his mother (Pam). The clip notes the genetic cause of Down Syndrome and focuses on the common problems associated with Down Syndrome. In particular, this clip emphasizes the learning capabilities of someone with Down Syndrome, and also highlights speech problems that sometimes accompany this disorder. 47

Watch Human Cloning - The Ethics N/A 50

Watch Genetic Counseling

A genetic counselor is interviewed. She talks about the purposes of genetic counseling, when genetic counseling is appropriate, and how a genetic counselor works with family members. 50

Behavior GeneticsCategory Title Description Duration Page

WatchThe Basics: Genetic Mechanisms and Behavioral Genetics

In this video, we learn about the types of things that behavioral geneticists study; we are given a review of basic genetics and inheritance, what correlation of traits means, and what family studies, adoption studies, and twin studies can determine. 51

Environmental Influences and ContextsCategory Title Description Duration Page

Watch Classic Footage of Little Albert Classic footage demonstrating conditioned fear in a baby 54