2 Non-Mendelian Genetics Some traits don’t follow the simple dominant/recessive rules that Mendel first applied to genetics.Traits can be controlled by more than one gene.Some alleles are neither dominant nor recessive.
3 Incomplete DominanceOne allele is not completely dominant over another.The heterozygous phenotype is a blending of the two homozygous phenotypes.Example: four o’clock flowersrr=redww=whiterw=pink (blending of the two alleles)
4 Codominance Two alleles are both expressed as a dominant phenotype Coat color in cowsRR: RedWW: WhiteRW: Roan, white with red spots (NOT pink!)
5 Multiple-Allele Series CodominanceMore than two choices of alleles are present for a traitABO blood type has three allelesABO Blood types:If both A and B are present, type is ABNeither is recessiveIndividuals can be type A, B, AB, or O (recessive)
6 What is blood made up of? The red blood cells The white blood cells contain hemoglobin.Red blood cells transport O2 and CO2 to and from body tissues.The white blood cellsfight infection.The plateletshelp the blood to clotThe plasmaFluid which contains salts and various kinds of proteins.
7 Determining Blood Type (not actual shape or size of antigens)(not actual shape or size of antigens)(not actual shape or size of antigens)Determining Blood TypeProtein molecules found on the surface of RBC’s and in the blood plasma determine the blood type of an individual.Antigens are located on the surface of the red blood cellsAntibodies are in the blood plasma.
8 What are the different blood groups? Blood group A (IA, IA ), (IA, i) have A antigens on the surface of red blood cells and B antibodies in blood plasma.Blood group B (IB, IB ), (IB, i)have B antigens on the surface of red blood cells and A antibodies in blood plasma.
9 What are the different blood groups? Blood group AB (IA, IB ) have both A and B antigens on the surface of red blood cells and no A or B antibodies in blood plasma.Blood group O (i, i) have neither A or B antigens on the surface of red blood cells but have both A and B antibodies in blood plasma.
10 Blood transfusions – who can receive blood from whom? The transfusion will work if a person who is going to receive blood has a blood group that doesn't have any antibodies against the donor blood's antigens.
11 People with blood group 0 are called "universal donors" and people with blood group AB are called "universal receivers."
12 Rh Factor Refers to another antigen on red blood cells Dominant trait is to have the antigenRh+Recessive trait is not to have itRh-A person with Rh- blood will produce antibodies to Rh+ bloodCan be a problem in pregnancy
14 Review Males have an X and a Y chromosome Females have two X chromosomesThese chromosomes determine sex, so genes located on these chromosomes are known as sex-linked genes.
15 The X chromosome is much larger than the Y, so it carries more genes than the Y chromosome. Disorders that are sex-linked are much more common in males, because they would only need 1 recessive allele to have the trait; rather than the two recessive alleles the females need.
16 Hemophilia Recessive trait Disorder where individuals are missing the normal blood clotting protein.Uncontrolled bleeds from minor cuts or bruises.Female genotype:Male genotype:
17 Colorblindness Recessive Inability to see certain colors Female genotype:Male genotype:
18 Duchenne Muscular Dystrophy RecessiveProgressive weakening and loss of skeletal muscle.Defective version of gene that codes for muscle proteinFemale genotype:Male genotype:
19 EXAMPLES!!A woman who is heterozygous for normal vision marries a man who is colorblind. What are the chances of them having a son or daughter who is colorblind?**NOTE: You have to use X’s and Y’s, and read the punnett square separately for boys and girls!**
20 A woman who is homozygous for normal blood clotting marries a man who has hemophilia. What are the chances of them having a son or daughter with hemophilia?