Multiple Alleles Genetics Unit Biology 30 Mrs. S. Pipke-Painchaud

Multiple Alleles have 3 or more alleles for the same gene (or at a single locus) In Other Words – there are 3 or more alleles that create the different traits. at most one individual will have 2 alleles or 1 pair (unit factors exist in pairs.) in a species, however, many alternative forms exist

Example – ABO Blood Group this deals with the presence of antigens –These are like labels/ name tags on the blood cells. Each individual has 1 of 4 phenotypes –Type A –Type B –Type AB –Type O –What are you? urcesandProjects/grade8/i mages/red%20blood%20ce lls.jpg

The Info You Need To Know Gene designated is I (isoagglutinogen) –I = A antigen –I = B antigen –i = no antigen I A and I B are both codominant I A and I B are both dominant to I (type O) GenotypeAntigenPhenotype IAIAIAIA AA IAiIAiAA IBIBIBIB BB IBiIBiBB IAIBIAIB AB i NeitherO

Website Resoures Nobel Prize – Blood Typing Website: – dmore.htmlhttp://nobelprize.org/educational_games/medicine/landsteiner/rea dmore.html –View for animations and background info on blood types. Wikipedia – Blood Types – –Contains a chart of blood types by nation. Maps of the Distribution of Human Blood Types all over the World. – Sickle Cell Anemia Example: –

Did You Know? B is the rarest allele. 16% of the population have it. –Distribution of Blood Types mages/uchr_01_img0015.jp g g/ElementaryHemeWeb/LEARN%20AB OUT%20RBCS%20AND%20PLTS.htm

Wikipedia:

Practice If a person with Type A (Heterozygous) blood married and had children with a person who has Type B (Heterozygous) blood, what would the genotypic and phenotypic ratios be? –I A i X I B i IAIA i IBIB IAIBIAIB IBiIBi iIAiIAiii Genotypic Ratio: 1 I A I B : 1 I A i: 1 I B i: 1 ii Phenotypic Ratio: 1 AB: 1 A: 1 B: 1 O

Practice If you crossed a person with type 0 with heterozygous type B, what would the phenotypic ratio be? –ii X I B i –Phenotypic Ratio: 1 B : 1 O ii IBIB I Bi IBiIBi iii

Website Resoures Nobel Prize – Blood Typing Website: – dsteiner/readmore.htmlhttp://nobelprize.org/educational_games/medicine/lan dsteiner/readmore.html –View for animations and background info on blood types.