Anna and Kristoff are heterozygous for three traits (PTC taster, dimples and freckles). What is the...
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Transcript of Anna and Kristoff are heterozygous for three traits (PTC taster, dimples and freckles). What is the...
Anna and Kristoff are heterozygous for three traits (PTC taster, dimples and freckles). What is the chance of:1. Their child having the same characteristics as
them?2. Their child being recessive for all 3 traits?
Science Starter
Genetics After Mendel
Huh?
Incomplete Dominance One allele is not completely dominant over the other
Results in a combined phenotype Example: Snapdragons
Cross two pink snapdragons:
More than 2 alleles for a geneHuman Blood Type- IA, IB, i
Multiple Alleles
Two alleles are dominant
Codominance
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!)
Jerry Springer Genetics Problem
Genes carried on the X chromosome Males fully express all alleles on X chromosome
Example: color blindness, hemophilia, ALD
Sex Linked Genes
Colorblindness Test
Cross a colorblind male with a normal female
More than one gene controls a trait Examples: Human height, weight, eye color, skin color, hair color, etc.
Polygenic Inheritance
Lab: Human Inheritance
PedigreeA chart that shows the presence or absence of a trait within a family
= female or = express trait
= male or = carrier
Sample ProblemDimples 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.