1. Your Family Health History
Chapter Two
Your Family Health History
© 2011 McGraw-Hill Higher Education. All rights reserved.

2. Creating a Family Health Tree
Also called a genogram or genetic pedigree
Visual representation of your family’s genetic history
Illustrates the patterns of health and illness within a family
Pinpoints areas of special concern or risk for you

3. Sample Family Health Tree

4. What can you learn from your family health tree?
An early onset of disease is more likely to have a genetic component
The appearance of a disease in multiple individuals on the same side of the family is more likely to have a genetic correlation
© BannanaStock/PictureQuest

5. What else can you learn from your family health tree?
A family member with multiple cancers represents a greater likelihood of a genetic association
The presence of disease in family members who have good health habits is more suggestive of a genetic cause than is disease in members with poor health habits

6. You and Your Genes: The Basics of Heredity
The nucleus of every human cell contains an entire set of genetic instructions stored in our DNA (deoxyribonucleic acid)
DNA has four building blocks that can be arranged to form a distinct message (gene) that acts as the body’s instruction booklet
Within the cell’s nucleus, DNA is divided into 23 pairs of chromosomes (one set of each pair comes from each parent)
© Alamy Images

7. Chromosomes, Genes, and DNA

8. The Human Genome Project
Launched in 1990
An international collaboration between 20 groups in 6 countries
In April 2003, it was announced that the sequencing of the human genome was complete

9. The Human Genome Project Discoveries
Humans have only 20,000 to 25,000 genes (same as a mouse)
Found many potential applications in medicine and pharmaceuticals
Helped confirm that race has more to do with social and cultural interactions and has no biological basis
© Getty Images

10. The Role of Mutations A change in a gene is called a mutation
Alternate forms of the same gene are called alleles
Some mutations are harmful, other mutations can be beneficial, and some have no effect
Mutations allow for human diversity

11. Genetic Inheritance
Alternate forms of genes, called alleles, are responsible for traits such as eye color
Alleles can be dominant or recessive
Most characteristics (such as height or skin color) are determined by the interaction of multiple genes at multiple sites of different chromosomes
© Ned Frisk Photography/Brand X Pictures/Jupiterimages

12. Single-Gene Disorders
Some diseases are caused by the alteration (mutation) of a single gene
Autosomal dominant disorder: Mutated gene is on a dominant autosome
Autosomal recessive disorder: Two copies of a mutated gene on an autosome
Sex-linked disorder: Mutated gene is on the sex chromosome

13. Multifactorial Disorders
Many diseases and traits can result from interactions between genes and the external environment
Account for the majority of illnesses and death in the developed world
Heart disease is one example of a multifactorial disease

14. Multifactorial Inheritance in Personality and Behavior
Genes appear to play a role in personality and everyday behavior
Differing personality traits, sexual orientations, and inclination towards addiction may be caused by genetic differences

15. Chromosomal Disorders
An inherited disorder caused by the addition, loss, or alteration of an entire chromosome
May lead to fetal death or death within the first year of life
Individuals may exhibit a broad range of symptoms, called a syndrome, ranging from characteristic physical traits to developmental delays to growth abnormalities
Down Syndrome is an example of such a disorder

16. Genetic Counseling and Testing
Genetic counseling helps individuals and families understand genetics, evaluate risks, learn about diagnostic tests, and discuss treatment options
Popular tests include:
Diagnostic
Predictive
Carrier
Prenatal Screening
Newborn Screening
© Blend Images

17. Management and Treatment of Genetic Conditions
Treatments may include:
Dietary Modification
Medication
Environmental Adaptation
Gene Therapy

18. Implications of Genetic Research
Controversial issues in genetic screening and testing
Issues of privacy and discrimination
Workplace discrimination
Health insurance discrimination
Eugenics (selective breeding)