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Chapter 3
The Start of Life: Genetics and Prenatal Development
Learning Objectives
Key Terms and Concepts
Chapter Outline
Lecture Suggestions
Inheritability of Personality
The New Genetic Code
Fertility
Infertility
Teratogens
Scarr’s Theory of Genotype-Environment Interaction
Class Activities
Supplemental Reading List
Prentice Hall PowerPoint Presentation available online
Multimedia Ideas
Handouts
LEARNING OBJECTIVES
After studying this chapter, you should be able to:
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Understand the basics of heredity and how characteristics are transmitted genetically from biological parents to
their children.
Explain the diversity of human beings and the special case of multiple births.
Identify how the sex of a child is determined.
Discuss the basic mechanisms involved in the way genes transmit information.
Understand the impact of the mapping of the human genome.
Explain how human development can go awry.
Understand prenatal assessment and genetic counseling.
Explain the role of the environment in determining genetic expression.
Describe the strategies researchers use to resolve the question of the degree to which traits, characteristics, and
behavior are produced by genetic or environmental factors.
Recognize which characteristics are significantly influenced by heredity and which are more influenced by
environment.
Describe how a culture’s philosophical outlook might be determined by genetics.
Understand the role of genetics and environment in psychological disorders.
Explain how one’s genetic endowment can actively influence their environment.
Describe the process of fertilization.
Identify alternative routes to pregnancy.
Understand the stages of the prenatal period.
Explain how a pregnancy can end prior to birth.
Understand the threats to development during the prenatal period.
Describe how to optimize the prenatal environment.
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KEY TERMS AND CONCEPTS
gametes
fertilization
zygote
genes
DNA (deoxyribonucleic acid)
chromosomes
monozygotic twins
dizygotic twins
dominant trait
recessive trait
genotype
phenotype
homozygous
heterozygous
polygenic inheritance
fragile X syndrome
behavioral genetics
Down syndrome
sickle cell anemia
Tay-Sachs disease
Klinefelter’s syndrome
fertilization
genetic counseling
amniocentesis
chorionic villus sampling
ultrasound sonography
temperament
multifactorial transmission
infertility
artificial insemination
in vitro fertilization (IVF)
surrogate mother
active genotype-environment effects
passive genotype-environment effects
evocative genotype-environment effects
germinal stage
placenta
embryonic stage
fetal stage
fetus
teratogen
fetal alcohol syndrome (FAS)
fetal alcohol effects (FAE)
CHAPTER OUTLINE
I.
Heredity
A. Genes are the basic unit of genetic information.
1. Genes are composed of sequences of DNA (deoxyribonucleic acid) which
determine the nature and function of every cell.
2. Humans have over 100,000 genes.
3. Genes are arranged in specific locations and in a specific order along
46 Chromosomes, rod-shaped portions of DNA that are organized in 23 pairs.
a. One pair of chromosomes is provided by the mother; one by the father.
b. At the moment of conception, or fertilization, the 23 maternal and
23 paternal chromosomes unite within a single new cell, called a
zygote.
c. Through the process of mitosis nearly all of the cells of the body will
contain the same 46 chromosomes of the zygote.
d. The potential for the vast diversity of human begins resides in the
nature of the process that underlies the division of the gametes.
e. Gametes are the human sex cells, the sperm and ova, which are formed
in the adult human body in a process called meiosis.
f. Through the processes of meiosis, in which each gamete receives one of
the two chromosomes that make up the 23 pairs, and random
transformations of particular genes, the ultimate outcome is trillions of
possible genetic combinations.
4. Less than 3 percent of all pregnancies produce twins, and the odds are even
slimmer for three or more children.
a. Monozygotic Twins, form when a cluster of cells splits off from the
ovum resulting in genetically identical zygotes.
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b.
Dizygotic Twins, are produced when two separate ova are fertilized by
two separate sperm and are no more genetically similar than two
siblings.
c. Other kinds of multiple births (triplets, quadruplets, etc.) can form from
either mechanism.
d. Using fertility drugs increases the chances of having a multiple birth.
e. Racial and ethnic differences affect the rate of multiple births.
(1) Caucasian - 1 out of 86 dizygotic
(2) African American - 1 out of 70 dizygotic
5. The 23rd chromosome determines the sex of the child.
a. Each gamete carries one chromosome from each of the parent’s
23 pairs of chromosomes.
b. If a female’s 23rd pair of chromosomes are both Xs, an ovum will
always carry an X chromosome.
c. If male’s 23rd pair is XY, each sperm could carry either an X or a Y
chromosome.
d. The father’s sperm determines the sex of the child.
B. The Basics of Genetics
1. Gregor Mendel (mid-1800s), working with peas, observed that when two
competing traits were present only one could be expressed.
a. The trait that is expressed is called the Dominant Trait, the trait
which is present but not expressed is the Recessive Trait. Recessive
traits can only be expressed if they are paired with a corresponding
recessive trait.
b. The underlying genetic make-up of an individual is referred to as their
Genotype.
c. The actual outward appearance of a trait, that which is observable, is
referred to as a person’s Phenotype.
d.
e.
f.
g.
h.
i.
j.
k.
When alleles, or traits that may take alternate forms, are the same from
both parents, the organism is said to be Homozygous for that trait.
If the offspring receives different forms of the gene from its parents, it
is said to be Heterozygous.
Phenylketonuria (PKU), a genetic disorder in which a child is unable
to make use of phenylalanine, an essential amino acid, is produced
by a single allele, or pair of genes. Both parents have to pass on
the recessive gene that produced PKU in order for the child to
express PKU.
Few traits are governed by a single pair of genes. Most traits are the
result of Polygenic Inheritance, in which a combination of multiple
gene pairs is responsible for the production of a particular trait.
Genes also vary in terms of their reaction range, the potential degree of
variability in the actual expression of a trait due to environmental
conditions.
Some traits, such a blood type AB, are expressed in terms of a
combination of two genes, neither of which can be classified as purely
dominant or purely recessive.
Some genes are X-linked, meaning they are considered recessive and
are located only on the X chromosome. Males have a higher risk for
X-Linked disorders because they lack a second X chromosome to
counteract the genetic information that produces the disorder.
(1) Hemophilia
(2) Red-green color blindness
Humans have about 25,000 genes, making them not much more
genetically complex than some primitive species.
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2.
3.
4.
5.
6.
The most recent approach to the study of the effects of heredity on behavior and
development is called Behavioral Genetics.
a. Researchers are learning how behavioral difficulties (such as
schizophrenia) may have a genetic basis.
b. Researchers also seek to identify how genetic defects may be remedied.
c. Some genetic disorders are inherited (e.g., PKU).
d. Some genetic disorders are the result of genes that become physically
damaged.
e. Sometimes genes spontaneously change their form, a process called
spontaneous mutation.
f. Certain environmental factors, such as exposure to X-rays, can produce
malformed genetic material.
g. Some genetic disorders include:
(1) Down Syndrome the most frequent cause of mental retardation
results from the presence of an extra chromosome on the
21st chromosome pair.
(2) Fragile X Syndrome occurs when a particular gene is injured on
the X chromosome, leading to moderate mental retardation.
(2) Sickle-cell Anemia is a blood disorder that gets its name from the
shape of the red blood cells in those who have it.
The lesson of sickle-cell anemia is that genetic factors are
intertwined with environmental considerations and cannot be
looked at in isolation.
(3) Tay-Sachs Disease is an untreatable disorder that produces
blindness and muscle degeneration prior to death, which usually
occurs prior to age 6.
(4) One male out of every 400 is born with Klinefelter’s Syndrome, a
disorder resulting from the presence of an extra X chromosome that
produces underdeveloped genitals, extreme height, and enlarged
breasts.
Genetic Counseling is the discipline that focuses on helping people deal with
issues related to inherited disorders.
Blood, skin, and urine may be used to isolate and examine specific
chromosomes.
Possible genetic defects can be identified by assembling a karyotype, a chart
containing enlarged photos of each of the chromosomes.
Prenatal: Fetal development monitoring techniques:
a. Amniocentesis, between the 15th and 18th week of pregnancy, this
procedure examines the fetal cells in the amniotic fluid surrounding the
unborn fetus.
(1) Recommended if either parent carries Tay-Sachs, spina bifida,
sickle-cell, Down syndrome, muscular dystrophy, or Rh disease.
b. Chorionic Villus Sampling (CVS), performed at 8 to 11 weeks, a
needle is inserted into the placenta but not into the amniotic sac.
c. Embryoscopy, examines embryo or fetus during first 12 weeks, allows
for diagnosis of malformations.
d. Fetal blood sampling (FBS), performed after 18 weeks, used to detect
Down syndrome and most other chromosome abnormalities in the
fetuses.
e. Sonembryology, used to detect abnormalities in the first trimester, can
detect more than 80% of all malformations during the second trimester.
f. Sonogram, uses ultrasound to produce a visual image of the uterus,
fetus, and placenta.
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g.
Ultrasound, very high frequency sound waves are used to detect
structural abnormalities or multiple pregnancies.
7. The newest role of genetic counselors involves testing people to identity if they,
rather than their children, are susceptible to future disorders because of genetic
abnormalities.
8. More than 450 disorders can be predicted on the basis of genetic testing.
Handout 3-6 shows a sampling of DNA-based tests for abnormalities
Handout 3-7 Gene Therapy?
II. The Interaction of Heredity and Environment
A. The Role of the Environment in Determining the Expression of Genes
1. An individual’s Temperament, the patterns of arousal and emotionality that
represent consistent and enduring characteristics, may represent Multifactorial
Transmission, traits that are determined by a combination of both genetic and
environmental factors in which a genotype provides a range within which a
phenotype may be expressed.
2. Some genotypes are not as sensitive to the environment as others. Ultimately, it
is the unique interaction of inherited and environmental factors that determines
people’s patterns of development.
B. The Interaction of Heredity and Environment
1. The correct question is not whether behavior is caused by nature or nurture but
how much by nature and how much by nurture.
2. Scientists put laboratory animals bred to share genetic backgrounds in different
environments to explore the effects of these environments. Conversely, they use
genetically different animals in similar environments to determine the role of
genetics.
3. Scientists use human twins to study the effects of genes and the environment.
a. Differences between monozygotic twins separated at birth are most
likely but not always due to different environments.
b. If monozygotic twins are more similar than dizygotic twins on a
particular trait than we can assume that genetics plays a role.
c. People who are unrelated but share the same environment also tell us
about environmental influences.
d. Researchers also study biological parents and their children versus
adoptive parents and their children to see the effects of heredity versus
environment.
4. Bottom line: Virtually all traits, characteristics, and behaviors are the joint result
of the combination and interaction of nature and nurture.
C. The more genetically similar two people are, the more likely they are to share physical
characteristics (e.g., height, weight).
D. Genetics plays a significant role in intelligence; however, the environment is also a
significant factor.
E. Increasing evidence supports the conclusion that at least some personality traits have at
least some genetic components. Some personality characteristics found to be linked to
genetic factors are:
1. Neuroticism refers to the degree of moodiness, touchiness, or sensitivity an
individual characteristically displays.
2. Extroversion is the degree to which a person seeks to be with others, to behave
in an outgoing manner, and generally to be sociable.
3. Political attitudes, religious interests and values, even attitudes toward human
sexuality (albeit indirectly).
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F.
III.
Several psychological disorders have been shown to be related, at least in part, to genetic
factors:
1. Schizophrenia
2. Major depression
3. Alcoholism
4. Autism
5. Attention-deficit hyperactivity disorder
G. According to Sandra Scarr, the genetic endowment provided by parents to children can
determine genetic characteristics and influence their environment.
1. With Active Genotype-environment Effects, children focus on those aspects of
the environment that are most congruent with their genetically determined
abilities.
2. With Passive Genotype-environment Effects, a parent’s genes can produce an
environment that influences the child.
3. With Evocative Genotype-environment Effects, the child’s genes elicit a
particular type of response from the environment.
Prenatal Growth and Change
A. Fertilization, or conception, is the joining of sperm and ovum to create the
single-celled zygote from which human life begins.
B. Alternate Routes to Pregnancy
1. Fifteen percent of couples suffer from Infertility, the inability to conceive after
12 to 18 months of trying.
2. Infertility is produced by several causes:
a. the age of the parents
b. previous use of birth control pills, illicit drugs or cigarettes, STDs
c. men who have an abnormally low sperm count
d. women who have blocked fallopian tubes
e. the woman’s mother taking certain drugs during pregnancy
3. There are several alternative paths to conception.
a. Artificial Insemination is a process of fertilization in which a man’s
sperm is placed directly into a woman’s vagina by a physician.
b. In Vitro Fertilization (IVF) is a procedure in which a woman’s ova
are removed from her ovaries, and a man’s sperm are used to fertilize
the ova in a laboratory. The zygote is then implanted into the mother.
c. A Surrogate Mother, a woman who agrees to carry another person’s
child to term.
4. Evidence suggests that children conceived using reproductive technologies do
quite well in life.
5. The psychological adjustment of children conceived artificially is no different
than that of children conceived using natural techniques.
C. Developmentalists divide the prenatal period into three phases: the germinal, embryonic,
and fetal stages.
1. The Germinal Stage is the first and shortest stage of prenatal development,
which takes place during the first two weeks following conception.
a. It is characterized by methodical cell division and the attachment of the
organism to the wall of the uterus.
b. The baby is called a zygote at this stage.
c. The cells become specialized with some forming a protective layer
around the zygote, while others create the Placenta, which nourishes
the baby, and umbilical cord.
2. The second stage is called the Embryonic Stage, the period from two to eight
weeks following fertilization during which significant growth occurs in the major
organs and body systems.
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a.
b.
At this point the child is called an embryo.
The developing child is now composed of three layers:
(1) The ectoderm is the outer layer forming the skin, hair, teeth, sense
organs, the brain and spinal cord.
(2) The endoderm is the inner layer producing the digestive system,
liver, pancreas, and respiratory system.
(3) The mesoderm is sandwiched between the inner and outer layers,
and forms the muscles, bones, blood, and circulatory system.
3. The Fetal Stage begins about eight weeks after conception and continues
until birth.
a. The developing child is called a Fetus.
b. The fetus dramatically increases in size and weight, and organs become
more differentiated and operational.
c. By three months the fetus swallows and urinates.
d. By four months the mother will be able to feel her fetus move.
e. The fetus develops a wide repertoire of different activities.
(1) Can do somersaults
(2) Cry
(3) Hiccup
(4) Clench fist
(5) Open and close eyes
(6) Suck its thumb
(7) Respond to sound
f. Just as in all individuals, there are significant differences in the specific
nature of individual fetus’ behavior.
D. A miscarriage—known as a spontaneous abortion—occurs when pregnancy ends before
the developing child is able to survive outside the mother’s womb.
1. The embryo detaches from the wall of the uterus and is expelled.
2. Fifteen to 20 percent of all pregnancies end in miscarriage.
3. Abortion is the voluntary termination of pregnancy.
a. Some 1.2 million abortions occur annually in the United States.
b. Abortion involves a complex set of physical, psychological, legal, and
ethical issues.
E. Threats to Prenatal Development:
1. Certain aspects of mothers’ and fathers’ behavior, both before and after
conception, can produce lifelong consequences for the child.
a. Some of the most profound consequences are brought about by
Teratogens, environmental agents that produce birth defects.
b. At some phases of prenatal development, a teratogen may have minimal
impact; at other periods, consequences can be severe.
(1) A mother’s diet clearly plays an important role in bolstering the
development of the fetus.
(2) Research shows that mothers over 30 and adolescent mothers are at
greater risk for a variety of pregnancy and birth complications:
(a) Premature birth
(b) Low birth weight
(c) Down syndrome
(d) Higher infant mortality rates
(3) Adverse social and economic factors and lack of maternal prenatal
support may contribute to infant mortality.
(4) Illness in a pregnant woman can have devastating consequences:
(a) Rubella (German measles) prior to the 11th week can cause
blindness, deafness, heart defects, or brain damage.
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(b) Chicken pox and mumps may cause birth defects and
miscarriage, respectively.
(c) Syphilis and gonorrhea can be transmitted to the child.
(d) Babies born with AIDS (acquired immune deficiency
syndrome) can have birth abnormalities including small,
misshapen faces, protruding lips, and brain deterioration;
90 percent have neurological delays and deficits in motor
coordination, speech, and facial expression. In addition, they
are susceptible to infection. Survival past infancy is rare.
(5) Mother’s use of legal and illegal drugs poses serious risks to the
unborn child:
(a) Aspirin can lead to bleeding.
(b) Thalidomide caused missing limbs.
(c) DES (diethylstilbestrol) later caused cervical and vaginal
cancer in daughters.
(d) Marijuana restricts oxygen to the fetus.
(e) Cocaine restricts blood flow and oxygen, and babies are born
addicted and go through withdrawal. Babies are are also
shorter and weigh less, have serious respiratory problems
and birth defects or seizures, and it is often impossible to
soothe them.
(6) Alcohol, tobacco, and caffeine can disrupt the development of the
fetus:
(a) Just two drinks a day has been associated with lower
intelligence.
(b) Fetal Alcohol Syndrome (FAS) is a disorder caused by the
pregnant woman consuming substantial quantities of alcohol
during pregnancy potentially resulting in mental retardation,
delayed growth, and facial deformities.
(c) Fetal Alcohol Effects (FAE) results from alcohol
consumption during pregnancy and is a condition in which
children display some, but not all of the characteristics
of FAS.
(d) Smoking reduces the oxygen content and increases carbon
monoxide. Mothers can miscarry or babies are born with
abnormally low birth weight, and babies born to smokers are
shorter and may be intellectually delayed.
(e) Some studies show that large quantities of caffeine can hurt a
fetus.
(7) Fathers behavior may influence the prenatal environment:
(a) Second hand smoke may affect health of mother and fetus.
(b) Use of alcohol and illegal drugs may lead to chromosomal
damage that may affect fetus at conception and also create
stress in the mother.
LECTURE SUGGESTIONS
BRAIN DEVELOPMENT FROM CONCEPTION
The Secret Life of the Brain, PBS (2004)
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THE NEW GENETIC CODE
Begley’s article discusses the newly discovered exceptions to Mendel’s rules (and textbook’s claims). For
example, it is genetic dogma that children inherit 23 chromosomes from Mom and 23 from Dad. However,
new research shows that individuals can inherit both chromosomes from a pair from the same parent (that’s
how diseases like cystic fibrosis are inherited).
Source:
Begley, 5. (11-2-92). A new genetic code. Newsweek. pp. 77–78.
FERTILITY
Traditionally, women’s fertility ranged anywhere from two days to ten days a month. However, a study by
the National Institute of Environmental Health Sciences in Research Park, NC, published in the New
England Journal of Medicine (12-7-95) found that women are fertile for five days before ovulation as well
as on the day of ovulation. Researchers were surprised to find that having sex just one day after ovulation
will not result in a pregnancy. Kits are available which tell when a woman is ovulating. (For couples
wanting to avoid pregnancy, these researchers suggest either abstaining from sex, or using birth control
during this six-day period.)
According to the study, the probability of conception ranges from 10 percent when intercourse occurs five
days before ovulation to 33 percent when it happens on the day of ovulation. Daily intercourse results in the
highest chance of pregnancy, 37 percent. The study had some other findings: there is no evidence that the
timing of intercourse influences whether the baby will be a boy or a girl. Also, there is no sign that aging
sperm is more likely to produce babies with defects, although the study was too small to provide conclusive
evidence.
On average, couples have a 20 percent chance of getting a viable pregnancy each month. However,
according to Dr. Allen Wilcox, who conducted the study, “even couples who are very fertile are not fertile
in every cycle. We don’t understand why that is.” Results from another study show that women who drink
three or more cups of coffee a day reduce their chances of conception by 26 percent. It is believed that
caffeine disrupts the menstrual cycle and may lead to early pregnancy loss.
Source:
Fertility window placed at 6 days. Arizona Republic (12-7 -95).
INFERTILITY
“Infertility is defined as the inability to get pregnant after 1 year or more of regular sexual activity without
the use of contraception, or the inability to carry a pregnancy to a live birth. . . . Some specialists use
2 years as the cutoff point” (Jewelewicz, 1989, p. 170). Contrary to popular opinion, infertility rates are not
on the rise. In 1965, the U.S. infertility rate was 13.3 percent; in 1988 it was 13.7 percent. However,
estimates are that one sixth of all couples who try to conceive are sterile or infertile. Jewelewicz (1989)
cites several reasons for this:
1.
2.
There are more couples trying to conceive because the post WWII baby boomers are reaching the end
of their reproductive years.
The rise in sexually transmitted diseases, women entering the workforce and being exposed to
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3.
4.
5.
6.
occupational hazards that affect their fertility, and the possibility of being exposed to more
environmental toxins are all reasons hypothesized for increased infertility.
Women are delaying childbirth and increased age is related to decreased fertility.
Oral contraceptives and use of an IUD may account for some cases of infertility.
Because of second marriages, some couples seek to reverse previous surgical sterilizations.
More techniques are available and written about in the media so couples are more aware of help for
infertility.
It is estimated that over 3 million couples will seek reproductive help each year. The top five procedures
include:
in vitro fertilization (1W).
gamete intrafallopian transfers (GIFT).
intrauterine insemination (JUT).
zygote intrafallopian transfer (ZIFT).
intracytoplasmic sperm injection (ICSI).
There are some pros and cons about the new reproductive technologies. For example, before the 1970s,
only donor insemination—injection of sperm from an anonymous man into a woman—was available for
infertile women. Today, in vitro fertilization is a common choice where hormones are used to stimulate the
production of several ova, which are removed. The eggs are placed in a dish of nutrients, sperm are added,
and then the fertilized eggs are injected into the mother. Ova can be screened for genetic defects and
fertilized ova can also be frozen for use in the future. Sperm can also be frozen. Few states have legal
guidelines for these procedures. Consequently, problems that might arise include
genetic defects.
sexually transmitted diseases.
poor records of donor characteristics.
possibility that children from same donor may grow up together and marry.
use of genetic selection for the “perfect child.”
use of “surrogate mothers.”
Use Handout 33 to review some reasons for infertility and various solutions.
Sources:
Jewelewicz, R. (1989). Sexual and reproductive health. In Tapley, D. F., Morris, T. Q., Rowland, L. P.,
Weiss, R. J, Subak-Sharpe, G. J., & Goetz, D. M. (Eds.), The Columbia University College of
Physicians and Surgeons Complete Home Medical Guide (rev. ed.). New York: Crown.
Rutter, V. (March/April, 1996). Who stole fertility? Psychology Today. 46–47, 65–70.
You can call RESOLVE, a group that puts out information on infertility at 617-623-0744 (9–4 EST).
TERATOGENS
Teratogens (from the Greek tera meaning “monsters”) are any agents that may pass from the mother
through the placental barrier and affect the fetus. Teratogens are a major cause of birth defects. Use
Handout 3-4 to go with this lecture.
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Source:
Norwood, C. (1985, January). Terata. Mother Jones. pp. 15–21.
SCARR’S THEORY OF GENOTYPE-ENVIRONMENT INTERACTION
You may want to devise a lecture elaborating on Sandra Scarr’s theory of genotype-environment
interaction. In her chapter in the book The Emergence of Personality, Scan tells us about her background,
her training in behavioral genetics, and how her own four children taught her the most about individuality.
Scarr credits Plomin, DeFries and Loehlin (1977) for originally proposing three types of interaction:
passive genotype-environment interaction, where a parent’s genotype influences the kind of learning
environment provided for his or her children; an evocative genotype-environment interaction, where a
child’s genotype influences how others react to him or her; and an active genotype-environment
interaction, where a child’s genotype influences his or her reaction to and selection of environmental
experiences. Scarr makes the following points:
 a genotype and an environment are required for development;
 development is a result of nature and nurture;
 genes drive experience;
 experience is guided by genotypes that both push and restrain experiences;
 the genotype determines the responsiveness of the person to those environmental opportunities.
Scarr gives the following examples of each type of interaction:
An example of a positive passive kind of genotype-environment correlation can be found
in social skills. Parents who are very sociable, who enjoy and need social activity, will
expose their child to more social situations than parents who are socially inept and
isolated. The child of sociable parents is likely to become more socially-skilled, for both
genetic and environmental reasons. . . . An example of a negative passive genotypeenvironment correlation can also be found in sociability. Parents who are socially skilled,
faced with a child who is a social isolate, may exert more pressure and do more training
than they would with a socially more adept offspring. . . .The second kind of genotype
environment effect is called evocative because it represents the different responses that
different genotypes evoke from the social and physical environments. Smiley, active
babies receive more social stimulation than fussy, difficult infants. . . . Cooperative,
attentive preschoolers receive more pleasant and instructional interactions from the adults
around them than uncooperative, distractible children. . . . [P]eople who are considered
attractive by others receive more positive attention, are thought to be more pleasant,
desirable companions, and so forth. . . . The third kind of genotype environment effect is
the active, niche-picking or niche-building sort. People seek out environments they find
compatible and stimulating. . . . Our selections are correlated with motivational,
personality, and intellectual aspects of our genotypes. . . . Examples of active genotype
environment effect can be found in the selective efforts of individuals in sports,
scholarship, relationships in life (pp. 67–68).
Scarr argues that passive genotype-environment interactions are strongest when children are young and
under the strong influences of their parents. However, as they get older and move out into the world on their
own, active genotype-environment effects take precedence.
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Sources:
Plomin, R., DeFries, J. C., & Loehlin, J. C. (1977). Genotype-environment interaction and correlation in the
analysis of human behavior. Psychological Bulletin, 84, 309–322.
Scarr, S. (1987). Personality and experience: Individual encounters with the world. In J. Aronoff, A. I.
Rabin, & R. A. Zucker (Eds.), The emergence of personality. New York: Springer.
CLASS ACTIVITIES
THE NATURE-NURTURE ISSUE: LESSONS FROM THE PILLSBURY DOUGHBOY
David B. Miller uses a cooking metaphor to describe the intricate interactions between genetics/biology
(nature) and the environment/learning (nurture). In his metaphor, flour represents genes. He takes four
different food items, which represent four different developmental outcomes that all use flour as a base but
that have other ingredients that interact with the flour in unique ways.
1.
2.
3.
4.
Flour + salt + water + fried in shortening = flour tortilla
Flour + salt + water + baked without shortening = matzo
Flour + salt + water + yeast + baking = bread
Flour + salt + butter + cocoa + sugar + baking = brownie
Depending on how adventuresome you feel you can demonstrate this lesson in a variety of ways. You can
bring in an example of each ingredient (e.g., a bag of flour, a box of salt, some water, a can of shortening, a
packet of yeast, some butter, a can of cocoa, a bag of sugar, and perhaps a toy oven) and use them as props
to create the “developed” results (e.g., tortilla, matzo, bread, and brownie). You could actually mix some of
the ingredients and assign students to go home and finish them. Finally, you could assign small groups
ahead of time to make the various products and bring them to class, each group must explain how their
ingredients relate to real world human development (i.e., flour = genes, salt = culture, water = health,
baking/frying = home environment). Each group must explain their results. Miller suggests that the
metaphor of tortilla versus matzo show how similar ingredients (i.e., shared genes of identical twins) can
yield different developmental outcomes (i.e., different personalities, intelligence, etc.) due to different
environments (i.e., baking versus frying).
Gallagher’s book represents a journalist’s effort to compile the latest data from geneticists, psychoanalysts,
neuroscientists, and primatologists on the role of heredity versus environment. We add it here as a resource
for the above discussion.
Sources:
Miller, D. B. (1996). The Nature-Nurture Issue: Lessons from the Pillsbury Doughboy. In Ware, M. E. and
Johnson, D. E. (Eds.), Handbook of demonstrations and activities in the teaching of psychology,
volume II: Physiological-comparative, perception, learning, cognitive, and developmental.
Lawrence Erlbaum Associates: Mahwah, NJ. pp. 20 1-203.
Gallagher, W. (1996). I.D.: How heredity and experience make you who you are. Random House:
New York.
50
CRITICAL THINKING ACTIVITIES
Using the “rethink” questions in Chapter 3 assign your class to small groups. Each group should attempt to
answer one or two of the questions. Have a representative from each group share their groups’ answers with
the class.
Another way to use the “rethink” questions in the chapter is to assign either individual students or groups to
answer a predetermined number of questions in class or outside of class. As a motivator, announce that at
least two of the questions will be on the next test. Students may refer to their answers when taking the test,
as in an open book format.
CONCEPTION AND PREGNANCY
Use Handout 3–1 for this assignment. Pass out the handout before you discuss conception and pregnancy.
Tell students that some of the answers are in Chapter 2 and some they will have to find on their own using
other sources. This handout is also useful to use with a video about conception and pregnancy (e.g., The
Miracle of Life).
SUPPLEMENTAL READING LIST
Hall, G. C. N. & Barongan, C. (2002). Multicultural psychology. Upper Saddle River, NJ: Pearson
Education, Inc.
Healy, J. M. (1994). Your child’s growing mind: A practical guide to brain development and learning from
birth to adolescence. New York: Bantam Doubleday.
Heim, C. & Nemeroff, C. B. (2001). The role of childhood trauma in the neurobiology of mood and anxiety
disorders: Preclinical and clinical studies. Biological Psychiatry,49, pp. 1023-1039.
Miller, J. B. (1986). Toward a new psychology of women. Boston: Beacon Press.
Phillips, J. L. (1981). Piaget’s theory: A primer. San Francisco: W. H. Freeman and Company.
Pinel, P. J. P. (2003). Biopsychology (5th ed.). Boston: Pearson Education, Inc.
Reis, H. T., Collins, W. A., & Berscheid, E. (2000). The relationship context of human behavior and
development. Psychological Bulletin, 126 (6), pp. 844-872.
Schore, A. N. (2002). Dysregulation of the right brain: A fundamental mechanism of traumatic Attachment
and the psychopathogenesis of posttraumatic stress disorder. Australian and New Zealand Journal
of Psychiatry, 36, pp. 9-30.
Shin, L. M., Whalen, P. J, Pitman, R. K., Bush, G., Macklin, M. L., Lasko, N. B., Orr, S. P., McInerney, S.
C. & Rauch, S. L. (2001). An fMRI study of anterior ingulate function in posttraumatic stress
disorder. Biological Psychiatry, 50, pp. 932-942.
Siegel, D. J. (1999). The developing mind: How relationships and the brain interact to shape who we are.
New York: The Guilford Press.
51
Prentice Hall PowerPoint Presentation available online
MULTIMEDIA IDEAS
Biological Growth: Nature’s Child (Insight Media, 1991, 60 minutes)
Explores the nature-nurture controversy. Examines the influences of genetics on behavior,
concentrating on hereditary contributions to intelligence, temperament, personality, sex
differences, and mental illness. It also investigates the influence of environment on prenatal
development.
Brain: The Secret Life of the Brain, PBS DVD prenatal through old age.
Developmental Phases Before and After Birth (Films for the Humanities and Sciences, 28 minutes)
This program examines the development of the fetus in utero and the child during the first year.
Heredity and Environment (Insight Media, 1988, 30 minutes)
Describes the basic mechanisms of heredity and discusses the joint role of heredity and
environment in determining human characteristics and development.
High Tech Babies (Coronet/MTI Film and Video, 1987, 58 minutes)
Useful as a way of increasing students’ awareness of the issues surrounding the new reproductive
technology: in vitro fertilization.
Fetal Alcohol Syndrome and Other Drug Use During Pregnancy (CD with this book)
The Miracle of Life (NOVA)
Shows development from conception to birth using Nilsson’s microphotography techniques.
Actually presents footage of the fetus moving in utero.
Motherhood on Hold (Films for the Humanities and Sciences, 23 minutes)
In this program, a reproductive endocrinologist explains why a woman’s chances of conceiving
drop dramatically after the 20s, and four women discuss their own very different experiences in
trying to have children and the factors that shaped their choices in determining when to conceive.
Pregnancy and Substance Abuse (Films for the Humanities and Sciences, 28 minutes)
This program follows several couples through pregnancy and prenatal care. Former U. S. Surgeon
General C. Everett Koop talks about the risks of smoking, and Michael Dorris, author of The
Broken Cord, discusses his life raising an adopted son with fetal alcohol syndrome. Highly
recommended.
Psychological Development Before Birth (Films for the Humanities and Sciences, 22 minutes)
The development of the individual can be followed in utero. This program shows how it is possible
to determine the well-being of the fetus; when the fetus begins to react to sound; and how mothersto-be deal with pregnancy and prepare themselves for the birth.
52
HANDOUT 3–1
This handout can be used as an assignment to be completed before your lectures on conception and pregnancy or as a
review. The answers are:
CONCEPTION
1.
ovary—fallopian tube—uterus—uterine wall (fertilized) or vagina (unfertilized)
2.
penis—vagina—uterus—fallopian tube—egg (ovum)
3.
possible answers include blocked/damaged fallopian tubes, abnormal ovulation, pelvic inflammatory disease
(PD), endometriosis, damaged ovaries, hostile cervical mucus, fibroid tumor
4.
possible answers include low sperm count, dilated veins around testicle, damaged sperm ducts, hormone
deficiency, sperm antibodies
5.
possible answers include surgery, in vitro fertilization, hormone therapy, antibiotics, artificial insemination
PREGNANCY
1.
possible answers include cessation of menses, breast tenderness, nausea
2.
Stage 1: The Germinal lasts two weeks (from conception fill week 2); the cells divide and attach to the uterine
wall, and the baby is called a “zygote.”
Stage 2: The Embryonic stage lasts 6 weeks (from week 2 until week 8), and the cell layers (endoderm,
ectoderm, mesoderm) form; the baby is called an “embryo.”
Stage 3: The Fetal stage lasts 7 months (from week 8 until birth); all the child’s systems are developing
rapidly, and the child is called an “embryo.”
3.
possible answers are to see an obstetrician/midwife, eat healthy diet including calcium and multivitamin and
mineral supplements, abstain from caffeine, alcohol, nicotine, and unnecessary drugs, get plenty of rest, avoid
X-rays, and exercise moderately
4.
amniocentesis—fetal cells are taken via a needle from amniotic fluid
chorionic villus sampling (CVS)—samples of hairlike material taken from embryo
ultrasound sonography—high frequency sound waves produce an image of baby
5.
possible answers include alcohol, nicotine, X-rays, prescription drugs such as Thalidomide, illicit drugs such
as cocaine and marijuana, illnesses of the mother such as rubella, influenza, and AIDS
Adapted from Strong, B. (1994). The Resource Book: A Teacher’s Toolkit for Human Sexuality,
Chapter 13, Mayfield Publishing Company. Reprinted by permission of the publisher.
53
HANDOUT 3–2
Use this handout with your lecture on fertility and infertility.
HANDOUT 3–3
This handout shows various dominant and recessive traits and can be used when discussing heritability of traits.
Source:
McKusick, V. A. (1990). Mendelian inheritance in Man: Catalogues of Autosomal Dominant, Autosomal
Recessive, and X-linked Phenotypes (9th ed.). Baltimore, MD: Hopkins University Press.
HANDOUT 3–4
Use this handout to discuss possible teratogens. Straub suggests an activity where students decide which teratogens
they are exposed to every day as an interesting way for students to see that it is difficult to avoid all teratogens in our
present society. Have students notice if there is a gender difference. Is it important for expectant fathers to avoid
teratogens also?
HANDOUT 3–5
Use this handout to guide your students in their reflections on prenatal development.
54
HANDOUT 3–1
Facts About Conception and Pregnancy
Review your knowledge of conception and pregnancy by answering the questions below.
Conception
1.
Trace the journey of the egg in a woman’s body:
fertilized
ovary
—
—
unfertilized
2. Trace the journey of sperm cells from ejaculation to conception:
penis
—
—
—
—
3. List three possible reasons for infertility in women.
a.
b.
c.
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
4. List two possible reasons for infertility in men.
a.
b.
___________________________________________________________________________
___________________________________________________________________________
5. List and define three treatments for infertility.
a.
b.
c.
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
Pregnancy
1. List three early signs and symptoms of pregnancy.
a.
b.
c.
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
55
HANDOUT 3–1, page 2 – Conception and Pregnancy, continued
2. Name the three stages of prenatal development. How long does each stage last? What systems have developed?
What is the developing child called?
Stage 1:
Stage 2:
Stage 3:
3. List six important components of good prenatal care.
a.
b.
c.
d.
e.
f.
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
4. Name and describe three prenatal tests.
a.
b.
c.
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
5. Name six teratogens.
a.
b.
c.
________________________________
________________________________
________________________________
d.
e.
f.
_________________________________
_________________________________
_________________________________
Adapted from Strong, B. (1994). The Resource Book: A Teacher’s Toolkit for Human Sexuality,
Chapter 13. Mayfield Publishing Company. Reprinted by permission of the publisher.
56
HANDOUT 3–2
Fertility Problems and Solutions
Females
Problem
Damaged fallopian tubes
Abnormal ovulation
Pelvic Inflammatory Disease
(PID)
endometriosis
Damaged ovaries
Hostile cervical mucus
Fibroid tumor
Stress
Tipped uterus, fibroid tumors
Solution
Surgery, in vitro fertilization
Hormone therapy, antibiotics, in vitro fertilization
Antibiotics, surgery, change in birth control methods
Antibiotics, hormone therapy, surgery, artificial insemination
Surgery, antibiotics, hormone therapy
Antibiotics, artificial insemination, hormone therapy
Surgery, antibiotics
Relaxation techniques
Surgery
Males
Problem
Solution
Low sperm count
Antibiotics, hormone therapy, artificial insemination, lowered
testicular temperature
Surgery, lowered testicular temperature, antibiotics
Dilated veins around
testicle
Damaged sperm ducts
Hormone deficiency
Sperm antibodies
Chronic illness,
alcoholism, drug, abuse,
long-term use of marijuana
Pollutants
Stress
Surgery, antibiotics
Hormone therapy
Antibiotics, in vitro fertilization
Artificial insemination
Artificial insemination
Relaxation
Adapted from Jewelewicz, R. (1989). Sexual and Reproductive Health. In Tapley, D. F., Morris, T. Q.,
Rowland, L. P., Weiss, R. J., Subak-Sharpe, G. J., & Goetz, D. M. (Eds.). The Columbia
University College of Physicians and Surgeons Complete Home Medical Guide (Rev. ed.). New
York: Crow.
57
HANDOUT 3–3
Dominant and Recessive Characteristics
Characteristics in the left-hand column dominate over those characteristics listed in the right-hand column.
Dominant Traits
Recessive Traits
eye coloring
brown eyes
grey, green, hazel, blue eyes
vision
farsightedness
normal vision
normal vision
normal vision
normal vision
nearsightedness
night blindness
color blindness*
hair
dark hair
non-red hair
curly hair
full head of hair
widow’s peak
blonde, light, red hair
red hair
straight hair
baldness*
normal headline
facial features
dimples
unattached earlobes
freckles
broad lips
no dimples
attached earlobes
no freckles
thin lips
appendages
extra digits
fused digits
short digits
fingers lack 1 joint
limb dwarfing
clubbed thumb
double-jointedness
normal number
normal digits
normal digits
normal joints
normal proportion
normal thumb
normal joints
other
immunity to poison ivy
normal pigmented skin
normal blood clotting
normal hearing
normal hearing and speaking
normal-no PKU
susceptibility to poison ivy
albinism
hemophilia*
congenital deafness
deaf mutism
phenylketonuria (PKU)
* sex-linked characteristic
58
HANDOUT 3–4
Possible Teratogens
This list of suspected teratogens contains many common items. Most babies are born without defects, so the placenta
may be an effective barrier. Additionally, the timing of the exposure to a teratogen is critical to its impact on prenatal
development. Overall, more damage is likely early in the pregnancy when organ systems are developing.
Diseases
Chlamydia
Rubella (German Measles)
HIV
Toxoplasmosis
Pneumonia
Herpes
Syphilis
Tuberculosis
Gonorrhea
Scarlet Fever
Mumps
Influenza
Hexachlorophene
Amphetamines
LSD
Anticoagulant drugs
Sedatives
Caffeine
Tranquilizers
Diethylstilbestrol (DES)
Alcohol
Lithium
Anti-cancer drugs
Quinine
Barbiturates
Thalidomide
Cocaine
Marijuana
Mercury
Fumes from paints, solvents,
glues, dry-cleaning fluids
Radiation (X-rays, Video Display
Terminals)
Polychlorinated Biphenyls (PCBs)
Cat feces
Pesticides
Herbicides
Chemical dependency
Anemia
Young/older mother
Phenylketonuria
Stress
Drugs
Accutane
lodides
Antibiotics
Opiates
Aspirin
Smallpox vaccination
Nicotine
Vitamins in excess
Environmental Factors
Cadmium
Nickel
Insecticides
Manganese
Hair dyes
Lead
Noninfectious Maternal Conditions
Alcoholism
Rh + factor
Diabetes Mellitus
Source:
Norwood, C. (1985, January). Terata. Mother Jones. pp. 15–21.
59
HANDOUT 3–5
Journal Exercise 3
If possible, interview your mother and father (if this is not possible, try an aunt or uncle or a grandparent) about your
own prenatal development. Use the following questions to get you started.
Was this a planned pregnancy?
Was this your first baby?
How did you find out you were pregnant?
How did you feel?
Were you working?
When did you see a doctor?
Did you take vitamins?
When did you start feeling the baby?
When did you begin wearing maternity clothes?
What changes did your body go through?
What are some of the strongest memories you have of this pregnancy?
Did you have any prenatal tests?
How did your lifestyle change?
Did you smoke? Drink alcohol? Drink coffee or tea? Take any drugs?
Did you know the sex of the baby before the birth? Did you have a preference for a boy or a girl?
How did you feel when you found out the sex of your baby?
When did you decide on a name for the baby?
Did you attend any special classes or workshops about childbirth, nursing, etc.?
Did you know of any preexisting conditions?
Where were you living?
Were there any features/characteristics you were hoping the baby would have?
Were there any you were hoping the baby would not have?
How much of your spouse’s medical history did you know? In retrospect, how important would that have been?
What role/expectations did you have for this child?
What influenced your decision to have a child at this time?
Did you have any trouble conceiving? Did you expect to have any trouble getting pregnant?
Now, reflect on what you learned. How do you think your own pregnancy (or your wife’s) will be (was) the same or
different than your mother’s?
60
HANDOUT 3–6
Sampling of DNA Gene Tests
Adult polycystic kidney disease: Kidney failure and liver disease
Alzheimer’s disease: Late-onset variety of senile dementia
Amyotrophic lateral sclerosis (Lou Gehrig’s disease): Progressive motor function loss leading to paralysis
and death
Ataxia telangiectasia: Progressive brain disorder resulting in loss of muscle control and cancers
Breast and ovarian cancer (inherited): Early-onset tumors of breasts and ovaries
Congenital adrenal hyperplasia hormone deficiency: ambiguous genitalia and male pseudohermaphroditism
Cystic fibrosis: Thick mucus accumulations in lungs and chronic infections in lungs and pancreas
Duchenne muscular dystrophy (Becker muscular dystrophy): Severe-to-mild muscle wasting, deterioration,
weakness
Dystonia: Muscle rigidity, repetitive twisting movements
Fragile X: syndrome Mental retardation
Gaucher: disease enlarged liver and spleen, bone degeneration
Hemophilia A and B: Bleeding disorders
Hereditary nonpolyposis colon cancera: Early-onset tumors of colon and sometimes other organs
Huntington’s disease: Progressive neurological degeneration, usually beginning in midlife
Phenylketonuria: Progressive mental retardation due to missing enzyme; correctable by diet
Sickle-cell disease: Blood cell disorder; chronic pain and infections
Spinal muscular atrophy: Severe, usually lethal progressive muscle-wasting disorder in children
Tay-Sachs disease: Seizures, paralysis; fatal neurological disease of early childhood
61
HANDOUT 3–7
Gene Therapy?
Would you support the complete cloning of a human?
In what circumstances would you find it acceptable?
What are the ethical issues involved in using gene therapy to “improve” human beings, such as enhancing someone’s
eyesight or athletic abilities?
62