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How do we get blended traits?

How do we get blended traits?. Incomplete dominance. ________________________- The dominant allele will not fully cover up a recessive allele and the trait will be a result of the two blending or mixing together. How do we get blended traits?.

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How do we get blended traits?

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  1. How do we get blended traits? Incomplete dominance • ________________________- The dominant allele will not fully cover up a recessive allele and the trait will be a result of the two blending or mixing together.

  2. How do we get blended traits? • In carnations, incomplete dominance can be seen in flower color: • red (RR) pink (Rr)white (rr) • 1. Cross two pink carnations ______x______ Rr Rr Possible genotypes of offspring: Possible phenotypes of offspring: R r RR= ¼ Rr= 2/4 Rr=1/4 RR Rr Rrrr R r Red= ¼ Pink= 2/4 White= ¼

  3. How do we get blended traits? 2. Cross a red and a pink carnation: _______x_______ Possible genotypes of offspring: Possible phenotypes of offspring: RR Rr RR: 2/4 Rr: 2/4 R R Red: 2/4 Pink: 2/4 R r RR RR RrRr

  4. Practice Problems: Incomplete Dominance- pg. 4 • List all possible phenotypes and the corresponding genotype for hair texture. • _______________________________________ • In humans, hair texture is due to an incompletely dominant trait. Straight hair (H) is incompletely dominant to curly hair (h). When crossed, they produce a heterozygous individual with wavy hair (Hh). Straight (HH), Wavy (Hh), and Curly (hh)

  5. Practice Problems: Incomplete Dominance- pg.4 • Using a Punnett square, cross a curly-haired person with a wavy-haired person. Hh hh HH: 0/4 Hh: 2/4 hh: 2/4 Straight: 0/4 Wavy: 2/4 Curly: 2/4 h h HhHh hhhh H h 0:2:2 • What is the genotypic ratio of the offspring? ________________________ • What is the phenotypic ratio of the offspring? _______________________ 0:2:2

  6. Practice Problems: Incomplete Dominance pg.4 • In guinea pigs, white fur (F) is incompletely dominant over yellow fur (f). When crossed they produce heterozygous offspring with cream-colored fur (Ff). • List all possible phenotypes and the corresponding genotype for fur color. _______________________________ White: FF Cream: Ffyellow:ff

  7. Practice Problems: Incomplete Dominance pg.4 • Using a Punnet Square, cross two guinea pigs with cream-colored hair. Ff _______________ X __________________ Show your lists of genotypes & phenotypes here! F f Genotypes: FF: Ff: ff: Phenotypes: White: Cream: Yellow: F f FF Ff Ffff ¼ 2/4 ¼ ¼ 2/4 ¼ • What is the genotypic ratio of the offspring? ________________________ • What is the phenotypic ratio of the offspring? _______________________ 1:2:1

  8. Can we express 2 traits at once?Pg. 5 • Codominance - When two different alleles are expressed __________ , at the same time (neither one is recessive). equally

  9. Can we express 2 traits at once?Pg.5 • Codominant alleles are written as capital letters with superscripts or subscripts (HR or B1). Since the trait is inherited from both parents, it is important to still use two ‘sets of letters’ as seen below: • The allele for red hair (HR) is codominant with the allele for white hair (HW) in cattle. Cattle that have the genotypes HRHW are called roan because their hair is a mixture of red and white hairs.

  10. Can we express 2 traits at once? HRHR = Red HRHW = roanHWHW= White Cross a red cow and a white bull: • Possible genotypes of offspring: • 2. Possible phenotypes of offspring: HR HR HW HW 0/4 4/4 0/4 HRHR : HRHW: HWHW: HRHW Genotypic Ratio: 0:4:0 HRHW HRHW HRHW Red: Roan: White: 0 4 0 Phenotypic Ratio: 0:4:0

  11. Can we express 2 traits at once? • HRHR= Red HRHW= roan HWHW= White • Cross a roan cow and a roan bull: HR HW • A. Possible genotypes of offspring: • B. Possible phenotypes of offspring: 1/4 2/4 1/4 HRHR: HRHW: HWHW: Genotypic Ratio: 1:2:1 HR HW HRHR HRHW HRHW HWHW 1/4 2/4 1/4 Red: Roan: White: Phenotypic Ratio: 1:2:1

  12. What are some examples of Codominance in humans? • In humans, red blood cells contain a protein called hemoglobin. It is the hemoglobin that gives the red blood cell its color and ability to pick up oxygen and carry to other cells.

  13. What is Sickle Cell Anemia? • https://www.youtube.com/watch?v=Qd0HrY2NlwY

  14. How is sickle cell anemia inherited? sufferers • Sickle cell _________are homozygous (HSHS) • Because all of their blood cells are affected by the sickle cell gene, these people are severely afflicted by the disease. Their red blood cells can becomes sickle shaped, rigid and live about 20 days. They also tend to get stuck in narrow blood vessels, which may cause complications.

  15. How is sickle cell anemia inherited? carriers • Sickle cell ___________are heterozygous (HAHS) • These carriers produce normal blood cells and sickle cell blood cells. Usually these people do not experience severe affects of this disease. Sickle cell anemia is more common in some parts of the world because being a carrier causes Malaria resistant. In places where Malaria is a problem, having 1 copy of the sickle cell gene is beneficial.

  16. How is sickle cell anemia inherited? normal • Cells with _________hemoglobin (no sickle cell anemia) are homozygous (HAHA) • Their red blood cells are disk shaped, soft/flexible and live for about 120 days.

  17. How is sickle cell anemia inherited? • Complete a punnett square to determine the chances of two sickle cell carriers having a homozygous normal child? • Genotype of parents: ________ x ___________ HAHS HAHS HA HS HAHS HA HS HAHA HAHA: ¼ Normal HAHS: 2/4 Carriers HAHS HSHS HSHS: ¼ Sufferer 25%

  18. Practice Problems: Codominancepg. 7 • In horses, pale cream color (C) is codominant to chestnut color (C). When crossed, they produce a heterozygous individual called a palomino (C C) which has a cream & chestnut coat. List all possible phenotypes and the corresponding genotype for coat color. ___________________________________________ Pale (CC) Palomino (CC’) Chesnut (C’C’)

  19. Practice Problems: Codominancepg. 7 • Using a Punnett square, cross a palomino horse with another palomino horse. CC’ ______x_______ C C’ Show your lists of genotypes & phenotypes here! C C’ CC CC’ CC= ¼ Pale CC’= 2/4 Palomino CC’ C’C’ C’C’= ¼ Chesnut 1:2:1 What is the genotypic ratio of the offspring? _______ 1:2:1 • What is the phenotypic ratio of the offspring? ______

  20. Practice Problems: Codominancepg. 7 • In chickens, black feather color (FB) is codominant to white feather color (FW). The heterozygous individual is a combination of black and white feathers that results in a checkered pattern (FBFW). • List all possible phenotypes and the corresponding genotype for feather color. • _________________________________________ Black (FBFB), Checkered (FBFW) White (FWFW)

  21. Practice Problems: Codominancepg. 7 • Using a Punnett square, cross a checkered chicken with a black chicken. FBFW _____x_____ FBFB FB FW Show your lists of genotypes & phenotypes here! FB FB FBFB FBFW FBFB: 2/4 Black FBFW: 2/4 Checkered FBFB FBFW FWFW: 0/4 White 2:2:0 • What is the genotypic ratio of the offspring? _________ 2:2:0 What is the phenotypic ratio of the offspring? _________

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