1. Chapter 2 Genetic and Environmental Foundations

2. Genotype and Phenotype
An individual’s genetic information
Phenotype
An individual’s directly observable characteristics
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3. Segment of DNA along the length of the chromosome
Genetic Foundations
Chromosomes
Rodlike structures within the cells that store and transmit genetic information
DNA
Deoxyribonucleic acid, the chemical substance that makes up chromosomes
Gene
Segment of DNA along the length of the chromosome

4. Mitosis and Meiosis Mitosis Process by which DNA duplicates itself
Produces new body cells containing the same genetic information
Meiosis
Process by which gametes (sex cells) are formed
Halves the number of chromosomes normally present
Leads to genetic variability

5. Autosomes, Sex Chromosomes, and Sex Cells
22 matching pairs of chromosomes
Sex
chromosomes
23rd pair of chromosomes
(XX = female, XY = male)
Gametes
Sex cells: sperm and ovum
Zygote
Formed when sperm and ovum unite

6. Twins Fraternal/Dizygotic
Result from release and fertilization of two ova
Identical/Monozygotic
Result when a single zygote separates to form two individuals
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7. Alleles Two forms of the same gene, one inherited from each parent
homozygous (both alleles are alike)
heterozygous (alleles differ)
Occur at the same place on both chromosomes in a pair

8. Dominant–Recessive Inheritance
Only the dominant allele affects children’s phenotypic characteristics
Carriers:
heterozygous (have one recessive allele)
can pass recessive trait to their children
Many serious diseases are product of recessive alleles

9. Incomplete Dominance Both alleles are expressed in the phenotype
Possible results:
combined trait
trait that is intermediate between the two
Example: sickle cell anemia

10. X-Linked Inheritance
Figure 2.4 X-linked inheritance
Figure 2.4

11. Genomic Imprinting, Mutation, and Polygenic Inheritance
chemical marker activates one allele in a pair
often temporary; may not occur in all individuals
Mutation:
sudden, permanent change in a segment of DNA
may affect one or two genes, or many
Polygenic inheritance:
characteristics influenced by many genes

12. Chromosomal Abnormalities
Down syndrome: caused by problems with 21st chromosome
Sex chromosome abnormalities:
caused by problems with X or Y chromosome
often not recognized until adolescence
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13. Reproductive Choices Genetic counseling
Prenatal diagnosis and fetal medicine
Reproductive technologies
Adoption
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14. Reproductive Technologies
Donor insemination
In vitro fertilization
Surrogate motherhood
New technologies
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15. Genetic Counseling Helps couples Recommended when
assess chances of hereditary disorders
choose best course of action in view of risks and family goals
Recommended when
couple has had difficulties bearing children
known genetic problems exist
woman is over 35

16. Prenatal Diagnostic Methods
Amniocentesis
Chorionic villus sampling
Fetoscopy
Ultrasound
Maternal blood analysis
Ultrafast magnetic resonance imaging
Preimplantation genetic diagnosis
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17. Adoption
Trends:
international adoption
adoption of older children
adoption of children with known developmental problems
Children typically exhibit some difficulties, but most fare well
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18. Environmental Contexts for Development
Family
Socioeconomic status and family functioning
Neighborhoods, towns, and cities
Cultural context
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19. Family Influences on Development
Direct influences
Indirect influences: effects of third parties
Adaptation to changes within and outside the family
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20. Socioeconomic Status (SES)
Social status:
years of education
prestige of one’s job and skill it requires
Economic status: income
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21. Socioeconomic Status and Family Functioning
SES is linked to:
timing of marriage and parenthood
family size
values and expectations for children
parents’ education and economic security
communication and discipline styles
investment in children’s cognitive development

22. Poverty Who Is Poor? 46 million Americans (15%) are poor
Those hit hardest are:
parents under age 25 with young children, especially single mothers
older adults who live alone, especially women
children, especially African- American, Native-American, and Hispanic children
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23. Homelessness
Most homeless families are women with children under age 5
Many homeless children suffer from:
developmental delays
chronic emotional stress
25% to 30% of school-age homeless children do not attend school

24. What Are the Risks of Affluence?
Alcohol and drug use
High levels of anxiety and depression
Unavailable parents:
lack of emotional closeness and supervision
excessive demands for achievement
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25. Importance of Regularly Eating Dinner as a Family
Figure 2.6 Relationship of regularly eating dinner with parents to affluent youths’ adjustment problems
Figure 2.6
(Adapted from Luthar & Latendresse, 2005.)

26. Benefits of Strong Community Ties
Beyond the Family
Benefits of Strong Community Ties
Neighborhoods: resources and social ties that promote development
Towns and cities: mold children’s and adults’ daily lives
Small towns: promote connection and participation
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27. Cultural Context
Cultural values and practices: shape daily life within and outside the family
Subcultures:
cooperative family structures help protect members from harmful effects of poverty
collectivism vs. individualism
Public policies: laws and programs designed to improve current conditions

28. Extended Families Three or more generations living together
More common in many minority cultures
Benefits:
reduce stress of poverty
provide assistance for all generations
create strong family bonds
transmit culture to next generation
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29. Individualistic and Collectivist Societies
People define themselves as separate entities
Independent self
Collectivist
People define themselves as part of a group
Interdependent self

30. Indicators of Children’s Health and Well-Being
Table 2.5 How Does the United States Compare to Other Nations on Indicators of Children’s Health and Well-Being?
Table 2.5
(Sources: Canada Campaign 2000, 2009; OECD 2010; U.S. Census Bureau, 2012; U.S. Department of Education, 2012.)

31. Percentage of Older Adults Living in Poverty
Figure 2.7 Percentage of older adults living in poverty in 20 industrialized nations
Figure 2.7
(Adapted from Luxembourg Income Study, 2011.)

32. How Much Does Heredity Contribute to Behavior? Heritability Estimates
Behavioral Genetics
How Much Does Heredity Contribute to Behavior?
Heritability Estimates
Obtained from kinship studies
Provide an estimate of proportion of individual differences in a trait attributable to heredity
Range from 0 to 1.00

33. Gene–Environment Interaction
Individuals respond differently to same environment because of genetic makeup
Similar responses can result from different gene–environment combinations
Figure 2.8 Gene–environment interaction, illustrated for intelligence by three children who differ in responsiveness to quality of the environment
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34. Canalization
Tendency of heredity to restrict development of some characteristics to just one or a few outcomes
Ensures development of species-typical skills under many rearing conditions
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35. Gene–Environment Correlation
Passive correlation
Evocative correlation
Active correlation: niche-picking
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36. Epigenesis
Development results from bidirectional exchanges between heredity and all levels of environment
Genes affect behavior and experiences
Experiences and behavior affect gene expression

37. The Epigenetic Framework
Figure The epigenetic framework
Figure 2.10
(Adapted from Gottlieb, 2007.)

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