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1. Introduction

2. Fact or Fiction?

3. The Genetic Code

4. From One Cell to Many

5. From Genotype to Phenotype

6. Chromosomal and Genetic Abnormalities

7. Closing Thoughts

Introduction

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[Video: Heredity and Environment Introduction]

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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.

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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

What Genes Are

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How are proteins made?

allele:A variation that makes a gene different in some ways from other genes for the same characteristics.

What makes a child who he is?

The Beginnings of Life

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gamete: A reproductive cell (a sperm or ovum).

New Cells New FunctionsHow do genes work in combination to build a person?

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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.

What are the possible gene combinations in a zygote?

Moth

er’

s t

wo

gen

es

Father’s two genes

F1M1

F1M2

F2M1

F2M2M2

M1

F1 F2

Gene-Gene Interactions

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genotype: An organism’s entire genetic inheritance, or genetic potential.

phenotype: The observable characteristics of a person.

23rd Pair

Phenotype Genotype Next Generation

1. XX Normal woman Not a carrier No color blindness from mother

2. XY Normal manNormal X from mother

No color blindness from father

3. XX Normal woman Carrier from fatherHalf 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 motherHalf her children will inherit her X. The girls with her X will be carriers; the boys with her X will be color-blind.

5. XYColor-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. XXColor-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 Complicationsx-linked: Referring to a gene carried on the X chromosome.

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The X indicates an X chromosome with the X-linked gene for color blindness

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

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Binge Drinking Among 14,000 Students in 119 Four-Year Colleges

44%56%

Binge-drinking episode

No binge-drinking episode

44%56%

What effect do college policies have on the drinking behavior of college students?

Addiction

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BAN

NO BAN

abstinence

binge-drinking

39%

29%

48% 16

%

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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?

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Practical Applications

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What do you know about your

biochemistry? No thanks

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.

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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: 3D ultrasound]

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Genetic Counseling and Testing

[Audio: Fetal Heartbeat]

Closing Thoughts

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What are some examples of how genes and environment have interacted to influence your development or the development of someone you know well?