6d. Blood Typing Chapter 7.1 & 7.2

Blood types There are several different blood types a person can inherit The possibilities: A+, A-, B+, B-, O+, O-, AB+, AB-

Blood types have 3 modes of inheritance Blood type exhibits Codominance, Polygenic and Multiple Allele inheritance Codominance A is dominant and B is also dominant Therefore is someone inherits and A and a B, their phenotype is AB O is recessive to both A & B

Polygenic When you inherit your alleles from your parents you get the following: The “letter” A, B or O AND The Rh Factor + or – (+ is dominant, - is recessive) Therefore, your blood type is polygenic because you have 2 sets of genotypes giving 1 phenotype Example Blood type: A+

Multiple Allele Traits This mode of inheritance is when you have more than 2 alleles in the gene pool For example: Sally has Blood type: AB Bob has Blood type: O * The Gene pool consists of A, B & O BUT you will only receive 2 of the 3 available. (Why? You only have 2 shoes)

Writing Blood Type genotypes There are 2 ways you can write the blood types Using the letter I/i indicates dominance IAi or IAIA = blood type A IBi or IBIB = blood type B IAIB = Blood type AB ii = Blood Type O OR Not Using the letter I/i you need to remember dominance AA or AO= blood type A BB or BO = blood type B AB = Blood type AB OO= Blood Type O

Let’s Practice: IAIA IBi ii IAIB What is the phenotype for? Type A Type B Type O Type AB

Let’s Practice Punnett Squares Show a cross between IAi and IBIB IA i IB IAIB IBi IBi IAIB

Let’s Practice more Punnett Squares Gertrude has type AB- blood, and she has babies with Thomas who has type O+ blood (he is heterozygous for rh) What could their babies be? Gertrude = IAIB-- ii+- Thomas = IA- IA- IB- IB- i+ IAi+- IAi+- IBi+- IBi+- i+ IAi+- IAi+- IBi+- IBi+- IBi-- i- IAi-- IAi-- IBi-- IAi-- IAi-- IBi-- IBi-- i-