Transcript blood types
You Inherited Your Blood Type • Blood is the bodily substance most commonly found at the scene of a crime or on a person, clothing, or a weapon potentially associated with a crime. • The presence of antigens on cells is genetically determined. • Every person can inherit two A, B or O blood type antigens – one from the mom & the other from the dad. You Inherited Your Blood Type Antigens A & B are called Codominant. O (absence of both antigens) is recessive. Genotypes or Antigens AA or AO Phenotype or Blood Type A BB or BO B AB AB OO O You Inherited Your Blood Type • Punnett squares are used to predict the probable genes you inherit from your parents. • Biology Vocabulary review: • Homozygous – same alleles (or antigens) = AA or BB or OO • Heterozygous – different alleles (or antigens) = AO or BO or AB You Inherited Your Blood Type • What is the probability (or possibility) of blood types if a mother (AA) has a child with a father (AO)? • Do a punnett square using dry erase boards. • Show genotypes and phenotypes as well as ratios (fractions & percentages). • A refresher is next. You Inherited Your Blood Type A A AA A AA GENOTYPE PHENOTYPE AA – 2/4 (50%) Type A – 4/4 (100%) AO – 2/4 (50%) Type B – 0/4 BB – 0/4 Type AB – 0/4 BO – 0/4 Type 0 – 0/4 AB – 0/4 O AO AO AA X AO OO – 0/4 You Inherited Your Blood Type • Do the following crosses on the dry erase boards provided. • Pick a partner. Work in collaborative pairs. • Assessment: Self & Peer Review – check your work & your partner’s work. • 1. BB x BO You Inherited Your Blood Type • Do the following crosses on the dry erase boards provided. • Pick a partner. Work in collaborative pairs. • Assessment: Self & Peer Review – check your work & your partner’s work. • 2. AA x AB You Inherited Your Blood Type • Do the following crosses on the dry erase boards provided. • Pick a partner. Work in collaborative pairs. • Assessment: Self & Peer Review – check your work & your partner’s work. • 3. AB x AB You Inherited Your Blood Type • Do the following crosses on the dry erase boards provided. • Pick a partner. Work in collaborative pairs. • Assessment: Self & Peer Review – check your work & your partner’s work. • 4. AO x AO You Inherited Your Blood Type • In the Rh blood system, people are classified as either Rh positive or Rh negative. • Rh positive have the Rh antigen. • Rh negative do NOT have the Rh antigen. • Rh positive can receive Rh negative blood, but Rh negative cannot receive Rh positive blood. This can cause serious transfusion reactions. You Inherited Your Blood Type • What would be the problem if an Rh positive father has a child with an Rh negative mother? What might happen with future pregnancies? • Distributed Summarizing: Use Numbered Heads = Choose a partner. The one with the earliest birthday in the year is #1, the later birthday is #2. • Discuss the possibilities of the problem listed above. You Inherited Your Blood Type • Blood typing is useful in forensics because it shows that two samples did not have the same origin. • This information is called “exclusion” & is an important aspect of criminology that has freed many criminal suspects as well as those who were wrongly convicted. You Inherited Your Blood Type • Blood typing is also used to exclude people in paternity cases. • Blood typing cannot prove a man IS the father, but may be useful in showing he IS NOT the father. DNA testing would be the next step. • Blood typing can give information to narrow down a list of possible suspects. You Inherited Your Blood Type % of people with A, B, AB & O blood types Type of Blood A % people with blood type 41 B 10 AB 4 O 45 You Inherited Your Blood Type % of people with Rh + & Rh - blood types Type of Blood Rh + % people with this type 85 Rh - 15 You Inherited Your Blood Type • With this information, you can calculate the possibility that a person would have a particular combination of blood types. • This was done in the O.J. Simpson Case when experts stated “…you would have to go to another galaxy to find a person with the same blood type as O.J. Simpson…” You Inherited Your Blood Type • “Who Dunnit” Blood Typing Lab • Lab is due before you leave at end of period. • Work with lab partners & table mates • READ THE DIRECTIONS! They are simple to follow. • Have Fun & Learn!!!! • Start Blood Spatter Lab Tomorrow!