Multiple Alleles

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Multiple Alleles

• Genetics Unit
• Biology 30
• Mrs. S. Pipke-Painchaud

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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 

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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?

http//www.rrsd.mb.ca/ResourcesandProjects/grade8/
images/red20blood20cells.jpg
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The Info You Need To Know

• Gene designated is I (isoagglutinogen)
• I  A antigen
• I  B antigen
• i  no antigen 
• IA and IB are both codominant 
• IA and IB are both dominant to I (type O)

Genotype Antigen Phenotype 
IAIA A A
IAi A A
IBIB B B
IBi B B
IAIB AB AB
i i Neither O
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• http//learn.genetics.utah.edu/units/basics/blood/
  types.cfm

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Website Resoures

• Nobel Prize Blood Typing Website
• http//nobelprize.org/educational_games/medicine/l
  andsteiner/readmore.html
• View for animations and background info on blood
  types.
• Wikipedia Blood Types
• http//en.wikipedia.org/wiki/Blood_type
• Contains a chart of blood types by nation.
• Maps of the Distribution of Human Blood Types all
  over the World.
• http//anthro.palomar.edu/vary/vary_3.htm
• Sickle Cell Anemia Example
• http//www.astrographics.com/GalleryPrintsIndex/GP
  2146.html

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Did You Know?

• B is the rarest allele.
• 16 of the population have it.
• Distribution of Blood Types
• http//anthro.palomar.edu/vary/vary_3.htm

http//www.uwosh.edu/med_tech/teaching/ElementaryH
emeWeb/LEARN20ABOUT20RBCS20AND20PLTS.htm
http//www.faqs.org/health/images/uchr_01_img0015.
jpg
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• Wikipedia http//en.wikipedia.org/wiki/ImageABO_
  blood_type.svg

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Practice
IA i
IB IAIB IBi
i IAi ii

• 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?
• IAi X IBi

Genotypic Ratio 1 IAIB 1 IAi 1 IBi 1 ii
Phenotypic Ratio 1 AB 1 A 1 B 1 O
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Practice
i i
IB IBi IBi
i ii ii

• If you crossed a person with type 0 with
  heterozygous type B, what would the phenotypic
  ratio be?
• ii X IBi
• Phenotypic Ratio
• 1 B 1 O

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Website Resoures

• Nobel Prize Blood Typing Website
• http//nobelprize.org/educational_games/medicine/l
  andsteiner/readmore.html
• View for animations and background info on blood
  types.

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The End of this concept
Try the assigned questions in the duotang-)