Review lecture 3 chapter 3
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Genes contain the instructions for making proteins and passing traits from parents to children. During reproduction, genes from the mother and father combine in embryos to form unique genotypes. As embryos develop into fetuses and babies, environmental factors also influence how genes are expressed as physical and behavioral phenotypes. Genetic counseling can help parents understand potential genetic conditions in their future children based on family histories.
Review lecture 3 chapter 3
- 2. 2 8. Closing Thoughts 1. Introduction 2. Fact or Fiction? 3. The Genetic Code 4. The Beginnings of Life 5. From Genotype to Phenotype 6. Nature and Nurture 7. Chromosomal and Genetic Problems
- 4. 4 Fact or Fiction? Fiction Fact 1. No two cells of the human body contain exactly the same material. 2. Not all individuals are born genetically unique. 3. All the genes a person has show up as observable traits. 4. Alcoholism is inherited.
- 5. What makes a child who he is? The Beginnings of Life 5 gamete: A reproductive cell (a sperm or ovum).
- 6. 6 The molecular beginnings of human development Deoxyribonucleic Acid (DNA): The chemical composition of the molecules that contain genes. chromosome: One of 46 molecules of DNA (in 23 pairs) that virtually each cell of the human body contains and that, together, contain all the genes. Other species have more or fewer chromosomes. gene: The basic unit for the transmission of heredity. Chromosome DNA
- 7. What Genes Are 7 How are proteins made? allele: A variation that makes a gene different in some ways from other genes for the same characteristics.
- 8. The chromosomes that make up the 23rd pair are the sex chromosomes. 8 Genotype: an organism’s entire genetic inheritance THE BEGINNINGS OF LIFE
- 9. 9 Monozygotic (MZ) twins: Twins who originate from one zygote that splits apart very early in development. Dizygotic (DZ) twins: Twins who are formed when two separate ova are fertilized by two separate sperm at roughly the same time. THE BEGINNINGS OF LIFE
- 10. New Cells New Functions How do genes work in combination to build a person? 10 genome: The full set of genes; instructions to make an individual member of a certain species. polygenic: A trait influenced by many genes. multifactorial: A trait affected by many factors, both genetic and environmental in expression. FROM GENOTYPE TO PHENOTYPE
- 11. What are the possible gene combinations in a zygote? Mother’stwogenes Father’s two genes F1M1 F1M2 F2M1 F2M2M2 M1 F1 F2 Gene-Gene Interactions 11 genotype: An organism’s entire genetic inheritance, or genetic potential. phenotype: The observable characteristics of a person. FROM GENOTYPE TO PHENOTYPE
- 12. 23rd Pair Phenotype Genotype Next Generation 1. XX Normal woman Not a carrier No color blindness from mother 2. XY Normal man Normal X from mother No color blindness from father 3. XX Normal woman Carrier from father Half her children will inherit her X. The girls with her X will be carriers; the boys with her X will be color-blind. 4. XX Normal woman Carrier from mother Half her children will inherit her X. The girls with her X will be carriers; the boys with her X will be color-blind. 5. XY Color-blind man Inherited from mother All his daughters will have his X. None of his sons will have his X. All his children will have normal vision, unless their mother also had an X for colorblindness. 6. XX Color-blind woman (rare) Inherited from both parents Every child will have one X from her. Therefore, every son will be color-blind. Daughters will be only carriers, unless they also inherit an X from the father, as their mother did. How do x-linked genes affect heredity? The 23rd Pair and X-Linked Color Blindness More Complications x-linked: Referring to a gene carried on the X chromosome. 12 The X indicates an X chromosome with the X-linked gene for color blindness FROM GENOTYPE TO PHENOTYPE
- 13. X-linked: Referring to a gene carried on the X chromosome. What happens to behavior as alcohol progresses from one brain part to another? Addiction 13 Binge Drinking Among 14,000 Students in 119 Four-Year Colleges 44% 56% Binge-drinking episode No binge-drinking episode 44% 56% NATURE AND NURTURE
- 14. What effect do college policies have on the drinking behavior of college students? Addiction 14 BAN NO BAN abstinence binge-drinking 39% 29% 48% 16% NATURE AND NURTURE
- 15. 15 Baby’s eyes reflexively follow the moving pattern Baby’s eyes do not follow the moving pattern Visual Acuity How are babies tested for nearsightedness? NATURE AND NURTURE
- 16. 16 Practical Applications 16 What do you know about your biochemistry? No thanks NATURE AND NURTURE
- 17. Not Exactly 46 Chromosomes What is Down syndrome? Down syndrome (Trisomy-21): A condition in which a person has 47 chromosomes instead of the usual 46, with 3 rather than 2 chromosomes on the 21st site, resulting in distinctive characteristics. 17 ©DenysKuvaiev/Alamy
- 18. 18 Genetic Counseling and Testing What do prospective parents learn from genetic counseling and testing? genetic counseling: Consultation and testing by trained experts that enable individuals to learn about their genetic heritage. Video: Prenatal Period: 3D ultrasound
- 19. Closing Thoughts 19 What are some examples of how genes and environment have interacted to influence your development or the development of someone you know well? FancyCollection/SuperStock