Multiple Alleles, Polygenic Traits, and Pedigrees Wednesday, October 25, 2011

Multiple Alleles Sometimes, there are more than just two alleles that affect a trait.

Multiple Alleles Sometimes, there are more than just two alleles that affect a trait. What trait have we talked about in class that has more than two alleles?

Multiple Alleles Sometimes, there are more than just two alleles that affect a trait. What trait have we talked about in class that has more than two alleles? Blood types! IA IB i

Multiple Alleles Sometimes, there are more than just two alleles that affect a trait. What trait have we talked about in class that has more than two alleles? Blood types! IA IB i Can you think of two other traits in a human that might have more than one allele?

Polygenic Inheritance Sometimes, there is more than one gene that affects a trait.

Polygenic Inheritance Sometimes, there is more than one gene that affects a trait. For example, there are many genes that affect human HEIGHT.

Polygenic Inheritance Sometimes, there is more than one gene that affects a trait. For example, there are many genes that affect human HEIGHT. There is not just one “tall” gene or “short” gene. Your height is caused by a combination of different genes.

Polygenic Inheritance Sometimes, there is more than one gene that affects a trait. For example, there are many genes that affect human HEIGHT. There is not just one “tall” gene or “short” gene. Your height is caused by a combination of different genes. A sign that a certain trait is affected by more than one gene is when there is a RANGE OF PHENOTYPES.

Genetic Diseases ________________: Disease where hemoglobin (the protein in red blood cells that carries OXYGEN ) is distorted and causes RED BLOOD CELLS to have a sickle or crescent shape.

Genetic Diseases Sickle Cell Anemia: Disease where hemoglobin (the protein in red blood cells that carries OXYGEN ) is distorted and causes RED BLOOD CELLS to have a sickle or crescent shape.

Genetic Diseases Sickle Cell Anemia: Disease where hemoglobin (the protein in red blood cells that carries OXYGEN ) is distorted and causes RED BLOOD CELLS to have a sickle or crescent shape. Causes shortness of breath, fatigue, and joint pain, among other symptoms. Caused by an autosomal recessive mutation for beta-hemoglobin.

Genetic Diseases Sickle Cell Anemia

Genetic Diseases Sickle Cell Anemia Sickled red blood cell Normal red blood cells

Genetic Diseases _____________________: Disease in which someone cannot tell the difference between certain colors.

Genetic Diseases Colorblindness: Disease in which someone cannot tell the difference between certain colors.

Genetic Diseases Colorblindness: Disease in which someone cannot tell the difference between certain colors. Is caused by a mutation on the X chromosome, so it is sex-linked.

Genetic Diseases ______________________: Disease that affects muscle coordination and leads to gradual decreases in brain functioning.

Genetic Diseases Huntington’s Disease: Disease that affects muscle coordination and leads to gradual decreases in brain functioning.

Genetic Diseases Huntington’s Disease: Disease that affects muscle coordination and leads to gradual decreases in brain functioning. Is caused by a DOMINANT mutation on an autosomal (non-sex) chromosome.

Genetic Diseases ______________________: Disease in which a person’s blood does not clot properly; patients can easily bleed to death.

Genetic Diseases Hemophilia: Disease in which a person’s blood does not clot properly; patients can easily bleed to death.

Genetic Diseases Hemophilia: Disease in which a person’s blood does not clot properly; patients can easily bleed to death. Caused by a mutation on the X chromosome, so it is sex-linked.

Genetic Diseases (this one’s not genetic, though!) _____________________: Disease transmitted through blood carried by mosquitoes.

Genetic Diseases (this one’s not genetic, though!) Malaria: Disease transmitted through blood carried by mosquitoes.

Genetic Diseases (this one’s not genetic, though!) Malaria: Disease transmitted through blood carried by mosquitoes. Causes high fever, joint pain, and vomiting.

Genetic Diseases (this one’s not genetic, though!) Malaria: Disease transmitted through blood carried by mosquitoes. Causes high fever, joint pain, and vomiting. Patients heterozygous for the sickle cell mutation are resistant to malaria.

Genetic Diseases ______________________: Disease in which a person cannot metabolize (break down) the amino acid phenyalanine.

Genetic Diseases Phenylketonuria (aka PKU): Disease in which a person cannot metabolize (break down) the amino acid phenyalanine.

Genetic Diseases Phenylketonuria (aka PKU): Disease in which a person cannot metabolize (break down) the amino acid phenyalanine. If left untreated, it can cause brain damage, resulting in mental retardation and seizures.

Genetic Diseases Phenylketonuria (aka PKU): Disease in which a person cannot metabolize (break down) the amino acid phenyalanine. If left untreated, it can cause brain damage, resulting in mental retardation and seizures. Caused by an autosomal recessive mutation.

Genetic Diseases Phenylketonuria (aka PKU): Disease in which a person cannot metabolize (break down) the amino acid phenyalanine. If left untreated, it can cause brain damage, resulting in mental retardation and seizures. Caused by an autosomal recessive mutation. No cure, but can be managed by strict dietary guidelines.

Genetic Diseases Avoid high-protein foods, like: MilkEggs NutsCheese SoybeansFish BeansChocolate ChickenPeas Steak and beef

Genetic Diseases Good foods:

Pedigrees Who can come to the board and remind us what the symbols for a pedigree are?

Pedigrees Who can come to the board and remind us what the symbols for a pedigree are?