2. Earliest Development The Interaction of Heredity and Environment

3. Beginning of Life Gametes from male and female join –Ovum and sperm Fused gametes create zygote

4. At the moment of conception (a), humans receive 23 pairs of chromosomes (b), half from the mother and half from the father. These chromosomes contain thousands of genes, shown in the computer-generated map (c).

5. The Contents of a Single Human Cell Genes –DNA Chromosomes –Rod-shaped DNA portions in 23 pairs –Contain genetic blueprint for individuals –Replicate through mitosis

6. And baby makes two or three or more!

7. Rising Multiples Multiple births have increased significantly over the last 25 years. What are some of the reasons for this phenomenon? Source: Martin et al. 2010.

8. What causes multiple births? Fertility drugs Age of mother Inherited differences Racial, ethnic, and national differences

9. Determining Sex 23 rd chromosome determines sex of child. Female: Two matching X Male: XY New techniques help to identify DNA in sperm; unwanted sex chromosomes can be discarded.

10. Mixing and Matching of Genes

11. Just the right type Genotype –Homozygous –Heterozygous Phenotype

12. Genetic Information Transmission

13. Uniquely Human? Humans have about 25,000 genes, making them not much more genetically complex than some primitive species. Source: Celera Genomics: International Human Genome Sequencing Consortium, 2001.

14. The Human Genome and Behavioral Genetics: Cracking the Genetic Code. In 2001, molecular geneticists mapped the sequence of genes on each chromosome. Number of human genes revised downward to 25,000. 99.9 percent of gene sequence shared by all humans. Human gene sequence supports field of behavioral genetics.

15. In what ways can information from the Human Genome Project affect your life?

16. When Development Deviates Causes –Genetics –Spontaneous mutation –Environmental insult

18. When Development Deviates Consequences Down SyndromeFragile X SyndromeSickle-cell AnemiaTay-Sachs DiseaseKlinefelter’s Syndrome

19. Genetic Counseling: Predicting the Future From the Genes of the Present Genetic counseling Focuses on helping people deal with inherited disorders issues Uses variety of data: Physical examination, karyotype Germ line therapy In amniocentesis, a sample of fetal cells is withdrawn from the amniotic sac and used to identify a number of genetic defects.

20. Prenatal Testing AmniocentesisCVSEmbryoscopyFBS SonoembryologySonogram Ultrasound sonography

21. In humans, the male sex cell (sperm) and the female sex cell (the ovum) provide the developing baby with 23 chromosomes each. A recessive gene responsible for a disorder may be passed on silently, revealing itself only when it is paired with another recessive gene. The field of behavioral genetics, a combination of psychology and genetics, studies the effects of genetics on behavior.

22. Sex cells (the ova and the sperm) are different from other cells because they: a. have twice the 46 chromosomes necessary so that when the cells combine and material is “spilled,” the appropriate number of chromosomes will still be there. b. each has half of the 46 chromosomes so that when they combine, the new zygote will have all the genetic information necessary. c. are younger than all other cells in the developing human body. d. are the only cells with chromosomal information.

23. According to Mendel, when competing traits are both present, only one trait, also known as the ______________ trait, can be expressed. a. homozygous b. recessive c. polygenic d. dominant

24. Just because a disorder has genetic roots does not mean that environmental factors do not also play a role. True False

25. How can the study of identical twins who were separated at birth help researchers determine the effects of genetic and environmental factors on human development?

26. The Interaction of Heredity and Environment

27. What do you think? A given behavior is not caused just by genetic factors, nor is it caused solely by environmental factors.

28. Studying Development: How Much Is Nature? How Much Is Nurture? Nonhuman animal studies –Controls genetics and environment –Offers substantial opportunities, but cannot guarantee generalization to humans Human studies –Includes adoption studies; twin studies; family studies; non-related people of similar background studies –Cannot control genetic background or human environments

29. When nurture becomes nature Transgenerational epigenetic inheritance: Individual’s life experiences can be passed down to children, grandchildren, and subsequent generations Why would the poor life choices we make in our youth, rather than those we might make later in life, have possible consequences for our children?

30. Do you have your mother’s eyes? Physical traits: Family resemblances More genetic similarity  more likely to share physical characteristics

31. Nature, Nurture, and Intelligence Relative contributions of nature and nurture highly researched Closer genetic link = greater correspondence of overall IQ scores

32. Genetics and IQ

33. Do we inherit our personality?

34. A link look Two of the “Big Five” personality traits linked to genetic factors –Neuroticism –Extroversion Less basic personality traits also linked –Political attitudes –Religious interests and values –Attitudes toward human sexuality Are some children born to be outgoing and extroverted? The answer seems o be “yes.”

35. What evidence supports this claim?

36. What about environmental influences? Culture Parental encouragement

37. Cultural Dimensions Can a culture’s philosophical outlook be determined by genetics? Religion may help mold temperament; temperament may make certain religious ideals more attractive.

38. Psychological Disorders: The Role of Genetics and Environment Several psychological disorders are related, at least in part, to genetic factors. Schizophrenia Major depression Alcoholism Autism ADHD

39. Genetics of Schizophrenia

40. Psychological Disorders: The Role of Genetics and Environment Genetics often produces a tendency toward a future course of development, but when and whether the characteristic will be displayed depends on the environment.

41. Gene-environmental Influence Sandra Scarr suggests three ways a child’s genetic predisposition may influence his or her environment. –Active –Passive –Evocative

42. Fundamental Principle Within debate about relative influence of nature and nurture –Role of genetics is often to produce tendency toward future course of development –Role of environment affects when and whether a certain behavioral characteristic will actually be displayed

43. Using a variety of approaches, developmental researchers have come to the general conclusion that virtually all traits, characteristics, and behaviors result from a combination and interaction of nature and nurture. Genetic influences have been identified in physical characteristics, intelligence, personality traits and behaviors, and psychological disorders.

44. There is some speculation that entire cultures may be predisposed genetically toward certain types of philosophical viewpoints and attitudes.

45. Most behavioral traits are a product of genetic influence and environmental factors. This is also known as ______________. a. systematic desensitization b. creative orientation c. genetic predetermination d. multifactorial transmission

46. Instead of asking if behavior is caused by genetic or environmental influence, we should be asking how much of the behavior is caused by genetic factors and how much is caused by environmental factors. True False

47. According to psychologist Jerome Kagan, differences in temperament between Chinese and American children suggest a culture’s philosophical outlook may be related to ______________ factors. a. environmental b. genetic c. cultural d. social

48. Are there personality characteristics that you believe you inherited from one or both or your parents? How might they have been affected by an environment different from the one you have experienced?