Chapter 2 Summary Notes
* Notes for educational purposes only-use with course textbook

 Bases for Genetic make-up
 Choices in
Reproduction
 Development and the
Family
 The Relationship
Between Heredity and
Environment

 Heredity and environment are foundations of development
 Genotype- genetic make-up
 Phenotype- observable characteristics

 Body composed of over a trillion cells
 Center of cell is nucleus which contains chromosomes
 Chromosomes- store and transmit genetic information
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DNA- double strain molecules that makeup chromosomes and contain genetic code
Gene- segment of
DNA molecule
Mitosis- cell duplication (each cell receives exact copy of genetic code)

 Gametes-sex cells (sperm 23 chromosomes and ovum 23 chromosomes)
 Meiosis- cell division that forms gametes
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No two gametes will ever be the same
Zygote- sperm and ovum unite at conception 46
Chromosomes
 Sperm are produced continuously; all ova are present at birth
 22 autosomes; 1 sex chromosome; xy- male; xxfemale

 Twins
– Fraternal (dizygotic) most common type
• Two ova are fertilized; genetic makeup similar to ordinary siblings
– Identical (monozygotic) one zygote separates into two clusters of cells that become two individuals; same genetic makeup
 Triplets (3); Quadurplets (4); Quintuplets (5);
Sextuplets (6), Septuplets (7)

 1978-1988- 17% single births; 33% twin births; 101% triplets and higher
 Trends in family planning and advances in reproductive technology assist in increase

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2 forms of genes occur at the same place on the autosome- father & mother
Homozygous- alike genes from both parents (inherited trait)
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Heterozygousdifferent genes from both parentsrelationship of genes determine trait that will appear.
Dominant- recessive inheritance- a pattern one gene’s influence is exhibited
(heterozygous)

 Dominant- expressed gene
 Recessive- not expressed
 Carrier- heterzygous; pass recessive gene to his/her children

 PKU
 Cystic Fibrosis
 Sickle Cell Anemia
 Tay-Sachs disease
 Hemophilia
(Page 50 in text)

 Older women
 Women with more children
 Fertility drug clients
 African American Women (fraternal twins)
 Tall, normal, or overweight (fraternal twins)

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2 forms of each gene occur at the same place on the autosomes- 1 mother;
1 father
Homozygous- both genes are alike
Heterozygousrelationship between genes determine trait that will appear

 A pattern in a heterozygous relationship only one gene’s influence is exhibited
 Carrierheterozygous relationship passes recessive gene
 Dominantexpressed
 Recessive- not expressed

 PKU
 Sickle Cell Anemia
 Tay-Sachs Disease
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Cystic Fibrosis
Cooley’s Anemia
(Pages 50-51 in text)
 Genetically linked illnesses

 Codominance
– Both genes influence the person’s charateristics
– Sickle Cell Anemia

 Change in DNA segment
 Harmful genes
 By chance
 Or by hazardous substances in the environment

 X-linked inheritance- recessive gene is carried on the X-Chromosome
– Males more likely to be affected (sex chromosomes don’t match)
– Hemophilia
 Males may be at a disadvantage in other areas not necessary linked to X-linked inheritance- miscarriage and infant deaths
 Learning disability, behavior disorders mental retardation (Halpern, 1997)

 Pattern of inheritance where some genes are chemically marked in such a way that one pair is activated regardless of its makeup
– Diabetes in the father
– Asthma in the mother
– Fragile X syndrome (MR, autism) mother

 Defect occurs during meiosis (DNA)
 Down Syndrome
– 21 st chromosome contains extra genetic material
– Physical features- short, stocky build, flatten face, protruding tongue, almond shape eyes, possible heart and intestinal defects, speech problems, delayed motor and cognitive defects
– Increase chances of having a baby with Down
Syndrome with age of mother

 Either the presence of extra chromosome or the lack of one of the X chromosomes
 Triple X syndrome (XXX)- girl- verbal difficulties
 Turner syndrome- (XO) missing X-spatial relationships
 Klinefelter syndrome (XXY)- verbal difficulties

 Genetic Counseling- communication about chances of couples having a baby with hereditary disorders
 Prenatal diagnostic methods
– Page 55 in text

 Adoption
 In vitro fertilization
 Fertility drugs

 Family
 Friends
 School
 Experiences
 Society
 Culture

 Family as complex system
– Behavior of family affects those of other family members
 Influence is directed or indirect- third party can support or undermine other family relationships
 Family dynamic ever- changing system
 Can be modified by important life events
 Development status of each family member and historical time period effects families

 3 variables
– Years of education
– Job prestige and skills required
– Income
– SES may affect differences in child-rearing practices
– Lower- SES family may focus on external characteristics (obedience, neatness, cleanliness)
– Higher SES focus on psychological traits-curiosity
• Happiness, and self- direction
• As early as 2 nd year of life SES affects with cognitive and language development

 36 million people
 14% of the population
 Hardest hit
– Parents under 25 with young children
– Elderly who live alone
– Ethnic minorities
– Women
– 20% children; 32% Hispanic; 40% African
American; 32% Native American

 Parents in poverty
– Experience hassles and crises affecting childrearing ability
– Poor housing and dangerous neighborhoods increase stress levels of poor families
– Homeless children suffer from developmental delays, emotional stress, health problems, school absenteeism, poor academic performance

 Community impact on family
– Child abuse and neglect are greatest
• With weak family and community ties
• Family stress and child adjustment problems are reduced with strong family ties
• Safe neighborhoods and communities with physical and social support
• Influence well-being in adulthood
• Smaller towns- fewer culture experiences than citiesgreater community involvement and safer environments

 Cultures shape family interactions and community settings beyond the home
 American cultural values- independence
– Self-reliance, privacy
– Subcultures- groups of people with beliefs and customs that differ from those of the larger culture

 Extended family- 3 or more generations live together
 Survival poverty, prejudice and economic deprivation (McAdoo)
 More kin visits
 Reduce stress
 Grandmothers are significant
 Elderly have higher life satisfaction
 Strong Family bonds, child development
 Survival for future generations

 Individualism societies- people think of themselves as separate entities; concerned with their own goals (US)
 Collectivism societies- people define themselves as part of a group and stress group over individual goals