Child Development Chapter 4 How Children Develop Nature

Child Development: Chapter 4 How Children Develop Nature through Nurture Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

Chapter Outline l l l The Study of Genetics and Behavior The Interaction of Genes and Environment The Study of Culture and Behavior Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

The Study of Genetics and Behavior l l l How We Study Genes and Behavior How Do Genes Work? Genetic Disorders Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

Nature versus Nurture? Nature through Nurture! l l l Throughout history the idea of whether our lives are determined by our genes or by the environment has shifted from one extreme to the other. D. O. Hebb: asking whether behavior is due to nature or to nurture is similar to asking whether the area of a rectangle is due to its length or its width (Meaney, 2004). Genetic and environmental influences are entangled in complex ways. Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

How We Study Genes and Behavior l l Molecular genetics: Identification of particular genes to discover how these genes work within the cell. Behavioral genetics: Determining the degree of genetic basis for a behavior, a trait, or an ability through studies of twins and adopted children Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

Behavioral genomics: Research that links behaviors, traits or abilities with specific genes. Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

The Human Genome Project l l The Human Genome Project mapped all the genes that make up the human body http: //www. youtube. com/watch? v=ub. Qsao. HB xs. U&feature=fvw 25, 000 -30, 000 genes determine everything about our genetic inheritance. We know what only about half of these genes actually do. Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

Results of the Human Genome Project: Chromosome 12 Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

Our Genetic Beginnings l l l Egg and sperm unite to form a zygote. 23 chromosomes from each pair up to form 23 pairs of chromosomes. 22 are autosomes The 23 rd is the pair that determines the sex: XX or XY. The father’s sperm determines the sex of the child by contributing either an X or a Y chromosome Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

Female and Male Chromosomes Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

Chromosomes, Genes, DNA, and Bases (GATC) l l Chromosomes are made up of Genes, which are made up of DNA, which is made up of 4 nitrogenous bases: l l Guanine (G), adenine (A), thymine (T), cytosine (C) The order of the bases determines which proteins are produced which make the body develop and perform all its activities. Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

l l Which combination produces a protein? How to divide the series: ATCATCTTTGGTGTT How would you divide the following series of letters? Gotothegrocerystorepickupmilkcomehome Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

l NOT: Got oth egro ceryst orepick upm ilk comeho me BUT RATHER Go to the grocery store. Pick up milk. Come home. Scientists must find the combinations in the sequences that make sense. l Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

Mendelian Inheritance: Dominant and Recessive Genes l l Most genes are paired with a gene on the matching chromosome. One of these 2 paired genes may be dominant and one recessive. Your genotype contains all the genes in your body. Your phenotype is which genes are expressed in your body. Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

l l Dominant genes will be expressed in your phenotype. Recessive genes will only be expressed if they are paired with another recessive gene. Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

Eye color and genes Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

Recessive gene disorders l l Tay-Sachs disease Sickle-cell anemia Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

One gene: one outcome? l l l The field vole and the mountain vole: One gene determines whether they mate for life or “play the field”. Can this be true for human beings? What else would be involved besides (or in addition) to a particular gene? Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

Many genes: one outcome One gene: many outcomes l l Polygenic inheritance: many genes interact together to produce a particular trait or behavior Pleiotropic effects; Any single gene can have many very different effects. Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

Genetic disorders l Single gene disorders l l Tay Sachs disease PKU Sickle cell anemia Cystic fibrosis Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

The problem with the Ychromosome l l l The Y-chromosome is small and carries few genes. It pairs with an X-chromosome with lots of genes. Any recessive genes on the X-chromosome that do not have a partner on the Ychromosome will be expressed in the phenotype. Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

l l l Therefore, boys are more prone to genetic disorders than girls. For example Color-blindness Hemophilia Duchenne muscular dsytrophy Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

Genetic disorders l Chromosomal disorders: l l Down syndrome: one extra chromsome #21 Klinefelter syndrome: XXY Turner syndrome: XO Fragile X syndrome: One gene segment (CGG) on the X chromosome is repeated 200 times, rather than 5– 40 times. Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

Genetic counseling and testing l l l In each pregnancy, any couple statistically has a 3% chance of having a child with a genetically based disorder. Those at higher risk may have genetic counseling and/or testing: Family history of genetic disorders Blood tests for certain genes before pregnancy Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

l During pregnancy: l l l blood tests – alpha-feta protein test Amniocentesis Chorionic villus sampling (CVS) Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

Interaction of Genes and Environment l l How the environment shapes gene expression How genes shape the environmental influences Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

How the environment shapes gene expression l l Canalization: The degree to which the expression of a gene is influenced by the environment Epigenetics: A system by which genes are activated or silenced in response to events or circumstances in the individual’s environment Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

Interaction of genes and the experience of child abuse Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

How genes shape the environmental influences l l Passive gene-environment interaction: When a child’s family shares his own genetically determined abilities and interests. Active gene-environment interaction: When one’s genetic endowment becomes a driving force for children to seek out experiences that fit their genetic endowments. Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

l Evocative gene-environment interaction: When children’s genetic endowment causes them to act in a way that draws out or “evokes” certain responses from those around them. Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

Study of the role of genes in behavior: Behavioral genetics l Studies of adopted children l l l Concordance rate with biological parents and adoptive parents Studies of identical (MZ) twins compared with non-identical (DZ) twins Studies of identical twins reared apart http: //www. youtube. com/watch? v=REh. Ka 3_o HL 8 Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

The study of culture and behavior: Environment effects l Culture: behaviors, norms, beliefs, and traditions that promote the survival of a group in a particular environmental niche. l It is a way of describing similarities within one group of people and differences between groups of people. Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

Difference versus deficit l l Deficit model: other cultures do not live up to one’s own standards Difference model: other cultures must be understood in their own context Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

Cultural values: Individualism and collectivism l l l Individualism The cultural value that emphasizes the importance of the individual with emphasis on independence and reliance on one’s own abilities Collectivism: The cultural value that emphasizes obligations to others within your group http: //www. youtube. com/watch? v=4 u. Fa 0 h. BP q. OY Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

What are your cultural values? Agree or disagree: l l l l 1. I tend to do my own thing, and others in my family do the same. 2. To understand who I am, you must see me with members of my group. 3. I take great pride in accomplishing what no one else can accomplish. 4. To me, pleasure is spending time with others. 5. It is important to me that I perform better than others on a task. 6. I would help, within my means, if a relative were in financial difficulty. 7. I am unique—different from others in many respects. 8. I make an effort to avoid disagreements with my group members. 9. I like my privacy. 10. How I behave depends on whom I am with, where I am, or both. 11. I know my weaknesses and strengths. 12. I have respect for the authority figures with whom I interact. 13. I always state my opinions very clearly. 14. I would rather do a group paper or lab than do one alone. Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

Transmitting culture to children l American mothers promote independence in feeding: l Puerto Rican mothers promote interdependence in feeding: Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications

Conclusion l l l Genes influence the environment The environment influences gene expression The interaction is complex and research is ongoing on this important topic. BUT We now know that we are not formed entirely by our genes and we are not formed entirely by our environment. Child Development: An Active Learning Approach by Laura E. Levine and Joyce Munsch © 2011 SAGE Publications