Human Genetic Disorders How many chromosomes do you see in this picture?

p. 88Human Genetic Disorders

(text p. 150)

Genetic Disorder: an abnormal condition that a person inherits through genes or chromosomes. Some are caused by mutations in the DNA of genes Some by the structure or number of chromosomes

Human Genetic Disorders Types of Genetic Disorders:

1) Cystic Fibrosis: a genetic disorder where the body produces abnormally thick mucus in the lungs and intestines-caused by a recessive allele with mutations

2) Sickle Cell Disease: affects hemoglobin so the sickle red blood cells cannot carry as much oxygen as normal cells-caused by having two sickle cell co-dominant alleles

Human Genetic Disorders Types of Genetic Disorders:

3) Hemophilia: a genetic disorder in which a person’s blood clots very slowly or not at all-caused by a recessive allele on the X chromosome, more

common in males

4) Down Syndrome: a person’s cells have an extra copy of chromosome 21 (three chromosomes instead of two)-caused during meiosis when chromosomes fail to separate

correctly

Human Genetic Disorders Pedigree: a chart or family tree that tracks which

members of a family have a particular trait

Human Genetic Disorders p. 88-89Managing Genetic Disorders:

1) Karyotype: a picture of all the chromosomes in a cell2)Genetic Counseling: counselors that use tools such as karyotypes, pedigree charts and punnett squares to help them in their work; give advice on chances of passing on disorders3) Medical Treatment is available: physical therapy, medicine, education and job training

Review Questions Identify two major causes of genetic disorders in

humans. Which one is responsible for Down syndrome?

What is a pedigree? What is a karyotype? What is the purpose of a genetic counselor? Explain one genetic disorder and the cause of it.