Human Heredity

Human Chromosomes

Pedigree Chart

• How does this chart relate to colorblindness and other sex-linked genetic disorders?

• Blood Group Genes:

• What is the importance of the “O” blood type?

• What is the importance of the “AB” blood type?

• What are the differences between disorders caused by recessive, dominant, and co-dominant alleles?

Cystic Fibrosis

• Why is the CFTR gene important?

• For what reason might this mutation have been advantageous, or at least more bearable in the past?

Sickle Cell Disease

• What effect does hemoglobin have?

• Why might sickle cell disease cause damage to the brain, heart, and spleen?

• How might Malaria play a role in sickle cell disease?

How does the relationship between CF and Cholera, and the relationship between Sickle Cell Disease and Malaria relate to evolution?

Sex-Linked Genes

X Chromosome Inactivation

• What is this and how does it work in males and females?

Why are males at a higher risk for sex-linked genetic disorders?

Chromosomal Disorders

• What is nondisjunction?

• Why is Down syndrome also referred to as “trisomy 21”?

Sex Chromosome Disorders

• What is Turner’s syndrome?

• What is Klinefelter’s syndrome?

• How are these two conditions similar and different?

Genetic Disorder: Genetic Cause? Which gene/chromosome is affected?

Effects and Symptoms?

Life Expectancy and lifestyle changes?

Likelihood of passing on this disorder?

Current treatment?

Gene therapy?

Cystic Fibrosis Mutation of CFTR gene by deletion of 3 bases

Deformation of CFTR gene which makes chloride transfer impossible

Thick mucus makes breathing difficult, digestive problems

Most people die in their 20’s and 30’s, difficulty breathing and multiple treatments

Same as Sickle Cell Disease (Autosomal Recessive Pattern)

Inhalant to thin mucus

Currently being researched, ineffective using current methods

Sickle Cell Disease Change of one DNA base to form glutamic acid in place of valine, an amino acid

Hemoglobin gene – less soluble hemoglobin makes the red blood cell sickle shaped

Sickle shaped red blood cells cause damage to major organs, especially the heart, brain, and spleen

Between 42-48 years, treatment needed, vaso-occlusive crisis due to oxygen loss causing tissue damage

If one parent has sickle

cell anaemia (SS) and

the other has sickle-cell

trait (AS), there is a 50%

chance of a child's

having sickle-cell

disease (SS) and a 50%

chance of a child's

having sickle-cell trait

(AS).

When both parents have

sickle-cell trait (AS), a

child has a 25% chance

(1 of 4) of sickle-cell

disease (SS),

Bone marrow transplant, pain medication, vasodilation therapy and drugs

Currently being researched

Hemophilia One of two genes on the x chromosome control blood clotting. One of them is a recessive allele

X chromosome (sex chromosome) – recessive allele fails to form protein necessary for clotting

Blood cannot clot, simple cuts can kill.

Injections of clotting proteins is needed but life expectancy is not significantly altered

X-linked recessive, mother is a carrier even if she does not show symptoms, similar to Autosomal Recessive Pattern

Recombinant DNA forms protein

Recombinant DNA can be used to produce missing clotting protein, but not within the body

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