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Science Starter

Science Starter. Anna and Kristoff are heterozygous for three traits (PTC taster, dimples and freckles). What is the chance of: Their child having the same characteristics as them? Their child being recessive for all 3 traits?. Huh?. Genetics After Mendel. Incomplete Dominance.

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Science Starter

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  1. Science Starter Anna and Kristoff are heterozygous for three traits (PTC taster, dimples and freckles). What is the chance of: • Their child having the same characteristics as them? • Their child being recessive for all 3 traits?

  2. Huh? Genetics After Mendel

  3. Incomplete Dominance • One allele is not completely dominant over the other • Results in a combined phenotype • Example: Snapdragons

  4. Cross two pink snapdragons:

  5. Multiple Alleles • More than 2 alleles for a gene • Human Blood Type- IA, IB, i

  6. Codominance • Two alleles are dominant

  7. Jerry Springer Genetics Problem On a recent episode of Jerry Springer, a woman brought her husband on the show (who recently moved out) to get him to pay child support for their baby. He claims that the baby she just had is not his, that it is her boyfriend’s!!! His argument is that he has type A blood and his wife has type B blood. The baby’s blood type is O so there is no way that the child is his. They come to you to determine the paternity of the baby. Is there any chance that this baby is his? (Hurry up with your answer; the husband just threw his chair at the boyfriend and they are about ready to fight!)

  8. Sex Linked Genes • Genes carried on the X chromosome • Males fully express all alleles on X chromosome • Example: color blindness, hemophilia, ALD

  9. Colorblindness Test

  10. Cross a colorblind male with a normal female

  11. Polygenic Inheritance • More than one gene controls a trait • Examples: Human height, weight, eye color, skin color, hair color, etc.

  12. Lab: Human Inheritance

  13. Pedigree • A chart that shows the presence or absence of a trait within a family = female or = express trait = male or = carrier

  14. Sample Problem Dimples in the cheeks are inherited as a dominant trait on an autosome. Using the proper form and symbols, draw a pedigree chart, beginning with a heterozygous, dimpled father (Dd), and a nondimpled mother (dd). Show four children of the expected types: boys, girls, dimples and no dimples. Label your pedigree with phenotypes and genotypes.

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