3 Recognize a variety of intermediate patterns of inheritance (codominance and incomplete dominance). • Interpret autosomal inheritance patterns: sickle cell anemia including the relationship to malaria (incomplete dominance), cystic fibrosis (recessive heredity), and Huntington’s disease (dominant heredity).• Solve and interpret codominant crosses involving multiple alleles including blood typing problems. (Blood Types: A, B, AB and O and Alleles: IA, IB, and i). Students should be able to determine if parentage is possible based on blood types.Recognize that some traits are controlled by more than one pair of genes and that this pattern of inheritance is identified by the presence of a wide range of phenotypes (skin, hair, and eye color). (polygenic)• Understand human sex chromosomes and interpret crosses involving sex-linked traits (color-blindness and hemophilia). Students should understand why males are more likely to express a sex-linked trait.
4 GENES are more complicated than MENDEL thought 3 Patterns of DOMINANCEComplete DominanceIncomplete DominanceCodominance
11 Incomplete Dominance F2 generation HeterozygousA 1:2:1 ratio with 25% red, 50% pink & 25% white offspringRWRRRRWWRWWWHeterozygous
12 INCOMPLETE DOMINANCE DON’T SEE __________ expected _____ ratio in F2 generation_____________ organisms with one dominant and one recessive allele show a _________ in-between trait3:1HeterozygousBLENDEDImage modified from:
15 In radishes, the gene that controls color exhibits incomplete dominance. Pure-breeding red radishes crossed with pure-breeding white radishes make purple radishes. What are the genotypic and phenotypic ratios when you cross a purple radish with a white radish?Parents ________ x _________Genotype RatioPhenotype Ratio
16 codominance Not all alleles are dominant and recessive. Some alleles are equally strong and neither are masked by the other.Alleles which are equally strong are said to be "codominant“
17 codominanceWhen both alleles are present, they are both expressed in the phenotype.When expressing codominant alleles, both alleles are represented by different capitalized letters.
18 A very common phenotype used in questions about codominance is roan fur in cattle. Cattle can be red (RR = all red hairs), white (WW = all white hairs), or roan (RW = red & white hairs together). A good example of codominance.
19 What would be the genotype and phenotype ratio if a roan cow and a roan bull were crossed? x
22 GENES are more complicated than Mendel thought Some traits have ____________ allele __________= ____________________EX: blood typeAllele choices ___ ___ ___choicesMORE than 2MULTIPLE ALLELE TRAITABO
23 The pattern of sugars that is attached is determined by genes BLOOD TYPES have more than 2 allele choices = _________________________MULTIPLE ALLELE TRAITThe pattern of sugars that is attached is determined by genesAllele choices are:_____ ____ ____ABO
24 Multiple AllelesMultiple Alleles – more than 2 alleles in a population for a trait, but a person can only inherit two. (one from father, one from mother)
25 Codominance: in humans Blood Type:A & B are equally strong.(Co-dominant)O is recessive.IAi , IAIA is Type AIBi, IBIB is Type BIAIB is Type ABii is type O
26 CO-DOMINANCEBoth traits are expressed together (NO BLENDING) in heterozygotePersons with an A allele AND a B allele have blood type AB
29 Membrane proteins with _______ attached that help cells recognize self REMEMBERMembrane proteins with _______ attached that help cells recognize self= ______________sugarsGLYCOPROTEINS
30 BLOOD TYPES An A allele tells the cell to put “A” glycoproteins on its surface
31 BLOOD TYPES A B allele tells the cell to put a different “B” glycoproteinon its surface
32 BLOOD TYPES An O allele tells the cell NOT to put anything on the surface
33 A and B are CO-DOMINANT A cell with BOTH an A and a B allele has BOTH glycoproteins on its surface
34 A and AB see A as “like me” as Different! DONOR BLOODA and AB see A as “like me”B and O see Aas Different!IMMUNE SYSTEM ATTACKS!Body images modified from:
35 B and AB see B as “like me” as Different! DONOR BLOODB and AB see B as “like me”A and O see Bas Different!IMMUNE SYSTEM ATTACKS!Body images modified from:
36 O ____ can donate to EVERY BLOOD TYPE = _____________________ DONOR BLOODO____ can donate to EVERY BLOOD TYPE= _____________________Nothing on surface torecognize as “NOT SELF”UNIVERSAL DONORYOU DON’T HAVE ANYTHING I DON’T HAVE!Body images modified from:
37 Only AB sees AB as “like me” DONOR BLOODOnly AB sees AB as “like me”A, B, and O see AB as Different!IMMUNE SYSTEM ATTACKS!Body images modified from:
38 AB can only GIVE to AB BUT . . . ______ can RECEIVE FROMEVERY BLOOD TYPE= ________________________UNIVERSAL RECIPIENTBody image modified from:
42 OTHER BLOOD TYPES ____________________ IF: NO PROBLEMS Rh+MOM is _____ & BABY is ____Rh+MOM is _____ & BABY is _____Rh+Rh-Image modified from:
43 Can be a ___________ IF: Mom is _____ Baby is _____ PROBLEMCan be a ___________ IF: Mom is _____ Baby is _____Rh+Rh-1st baby OK but few baby cellsentering mom’s bloodstreamput mom’s immune system onalert for + cells.Next + baby, mom’s immunesystem can attack baby as it isgrowingMom given shot after 1st birth prevents thisImage modified from:
44 Anything that can trigger this immune response is called an antigen Anything that can trigger this immune response is called an antigen. An antigen can be a microbe such as a virus, or even a part of a microbe. Tissues or cells from another person (except an identical twin) also carry nonself markers and act as antigens. This explains why tissue transplants may be rejected.
45 What are the possible blood types of the offspring between a woman whose blood type is heterozygous A and a man who has blood type 0?
46 Blood Typing – Remember the antibody will bond to something if it is present