Genetic Disorders

Ch. 5 section 2

Causes

• Genetic Disorder: an abnormal condition that a person inherits through genes or chromosomes.

• Some are caused by mutations in DNA. • Others by the changes in structure or

Number of chromosomes.

Cystic Fibrosis

• The body produces abnormally thick mucus in the lungs and the intestines.

• Mucus makes it hard to breath. • The recessive allele is a result of a

mutation in which 3 bases are removed.

Sickle Cell Disease

• Affects the hemoglobin in red blood cells that carry oxygen.

• When oxygen levels are low the red blood cell has a sickle shape.

• Blot clots are common with this disease.

Hemophilia

• Disorder where a person’s blood clots very slowly.

• Occurs more in males than females. • People bleed a lot just from a small cut.

Downs Syndrome

• A person’s cells carry an extra copy of chromosome 21.

• Instead of a pair of chromosomes they have 3 in the 21st set.

• People with DS have a degree of mental retardation and heart defect are also common.

Pedigrees

• An important tool that geneticists use to trace inheritance of traits in humans.

• Chart or “family tree” that track which family member has a particular trait.

Karyotypes

• Picture of all the chromosomes in a cell. • Can help reveal if a person has the

correct number of chromosomes in his or her cells.

Dealing with genetic disorders

• People with disorders face serious challenges.

• Medical care and treatments can help people with some of these disorders.

• Most genetic disorders do not prevent people from living active and productive lives.

CH. 5 section 3

• Selective Breeding: selecting organisms with desired traits to be parents of the next generation.

• Inbreeding: crossing 2 individuals that have similar characteristics. (usually very similar)

• Hybridization: cross 2 genetically different individuals.

Cloning

• Can be used to produce offspring with desired traits.

• Clone: organism that has the exact same genes as the organism in which it was produced by.

• Researchers have cloned sheep and pigs.

Genetic Engineering

• Genes from one organism are transferred into the DNA of another.

• One type of Bacteria is genetically engineered to produce insulin that is used for people with Diabetes.

Gene Therapy

• Involves inserting copies of a gene directly into a person’s cells.

Concerns

• Long term effects are still in question. • could cause health problems or

environmental problems.

Human Genome project

• Genome: all the DNA in one cell of an organism.

• Goal is to identify the DNA sequence of every gene in the human genome.

• Humans contain at least 30,000 genes. • Average gene has about 3,000 bases.