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Snapdragons

Snapdragons. HUH?. http://www.dobermann-review.com/info/genetics/mendels_genetic_laws/Gregor%20Mendel.jpg. http://faculty.pnc.edu/pwilkin/incompdominance.jpg. Incomplete Dominance. Neither allele is completely dominant over the other allele A heterozygous “phenotype”

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Snapdragons

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  1. Snapdragons HUH? http://www.dobermann-review.com/info/genetics/mendels_genetic_laws/Gregor%20Mendel.jpg http://faculty.pnc.edu/pwilkin/incompdominance.jpg

  2. Incomplete Dominance • Neither allele is completely dominant over the other allele • A heterozygous “phenotype” • A mixture or blending of the two alleles

  3. Four-o’ clock flowers • Incomplete dominance • Neither Red (R) • or White (W) is dominant When a homozygous red flower (RR) Mixes with a homozygous white flower (WW), the alleles blend in the hybrid (RW) to produce pink flowers

  4. Andalusian Chickens • Incomplete dominance • Neither Black (B) nor White (W) are dominant The offspring of a black feathered chicken (BB) and a white feathered chicken (WW) are blue (BW) – BLUE HEN!!

  5. Codominance • Two equally dominant alleles are expressed at the same time • In separate cells! • Heterozygous phenotype will have both dominant phenotypes visible

  6. Shorthorn Cattle • Co-dominance • Homozygous red (RR) • Homozygous white (WW) The offspring of will have both red and white hairs (RW) The offspring are heterozygous and called “roan”

  7. Roan Horse http://search.vadlo.com/b/q?rel=2&keys=Dominance+Incomplete+Dominance+Codominance+PPT

  8. Sickle-Cell Anemia • Co-dominance • Caused by abnormally shaped Hemoglobin, the protein that red blood cells use to carry oxygen Normal hemoglobin is (RR) Sickle Cell shaped blood cells are (SS) People who are carriers (heterozygous) for the disease have a mixture of both normal and sickle cell red blood cells (RS)

  9. Problem: Codominance Show the cross between an individual with sickle-cell anemia (recessive) and another who is a carrier but not sick NS SS SS NS N S GENOTYPES: - NS (2) SS (2) - ratio 1:1 S S PHENOTYPES: - carrier (2); sick (2) - ratio 1:1

  10. Let’s Stop and Think… Let’s say there are two alleles for hair color trait red and blue What would be the resulting phenotype of a heterozygous pair if the alleles showed incompletedominance? A. Red B. Blue C. Purple D. Red and Blue patches

  11. Let’s Stop and Think… • Let’s say there are two alleles for hair color trait • red and blue • What would be the resulting phenotype of a heterozygous pair if the alleles showed codominance? • A. Red • B. Blue • C. Purple • D. Red and Blue patches

  12. MULTIPLE ALLELISM When there is more than 2 alleles possible for a given gene Think eye color, hair color, skin color! Allows for a larger number of genetic and phenotypic possibilities! DIVERSITY!

  13. Blood Typing IA i IA IA • Blood types are A, B, O, and AB. • AB blood is a co-dominant trait. • Both the A blood and the B blood need to be dominant in order to make a combination of co-dominant blood types, which is AB. • IA IA IA • IB IB • IB i

  14. BLOOD TYPES IA = A antigen on RBC IB = B antigen on RBC i = neither A nor B antigen Genotype Blood type IAIAor IAi A B IBIB or IBi IAIB AB O ii • 4 blood types • 3 alleles of the gene Antibody Anti – B Anti – A None Anti – A, Anti – B

  15. http://www.pennmedicine.org/health_info/images/19450.jpg

  16. http://image.wistatutor.com/content/feed/tvcs/blood_type5B15D.jpghttp://image.wistatutor.com/content/feed/tvcs/blood_type5B15D.jpg

  17. Universal Recipient Universal Donor

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