9. Pedigree Chart of a Dominant Trait The father does not have the dominant disease so he must have 2 recessive alleles; his genotype is hh The son has the dominant disease so he has to have at least one dominant allele. Is his genotype HH or Hh? One allele came from his father so his genotype is Hh.
10. Pedigree Chart of a Dominant Trait hh HH Hh What are the chances that future offspring of this couple will have this dominant disease? Use the genotypes of the parents to draw a punnett square.
11. Pedigree Chart of a Dominant Trait hh HH Hh All of the offspring have the dominant allele so 100% of their future children will have this dominant disease. H H h Hh Hh h Hh Hh
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13. Pedigree Chart of a Recessive Trait She must have 2 recessive alleles to have this disease. Her genotype is cc. The dad does not have this recessive disease so his genotype is either CC or Cc. Since he passed on one recessive allele to his daughter, his genotype is Cc.
14. Pedigree Chart of a Recessive Trait What are the chances that future offspring of this couple will have this recessive disease? Use the genotypes of the parents to draw a punnett square. Cc Cc cc
15. Pedigree Chart of a Recessive Trait Cc Cc cc C c C CC Cc c Cc cc Only 1 out of 4 offspring have the recessive disease (cc). There is a 25% chance of future offspring having the disease.
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22. Practice What percentages can be expected in the offspring of a cross between a female carrier for color blindness and a male with a normal color vision? Show your work with a punnett square.
23. Practice What percentages can be expected in the offspring of a cross between a female carrier for color blindness and a male with a normal color vision? Color blindness is a recessive trait attached to the X chromosome. A female carrier means heterozygous. female carrier X B X b male with normal vision X B Y X B X b Y X B Y X b Y X B X B X B X B X b 25% colorblind males 25% carrier females 25% normal males 25% normal females
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Editor's Notes
You must learn the symbols of the pedigree charts before you can start to learn how to interpret it. These are the symbols that represent a male and a female.
These symbols also represent relationships between people. some may have to each other.
These are examples of different types of symbols. These symbols would be the same for males or for females, except for X-linked carrier which is only used for females. So an affected male would be a square that is filled in completely. A deceased female would be a circle with a diagonal slash.
![Chromosomes ,[object Object],[object Object]](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)