Tuesday 1192016 Genetics Agenda Pedigrees Notes Pedigrees Activity
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Tuesday 1/19/2016 Genetics Agenda: Pedigrees Ø Ø Notes: Pedigrees Activity: Pedigree Worksheet Activity: Genetics Review Guide GENETICS EXAM WEDNESDAY/THURSDAY 1/20 -1/21/2016 Homework/Class Work: Pedigree Worksheet and Review Guide due Wednesday/Thursday 1/20 -1/21/2016 for 30 Points
Understanding a Pedigree Chart A family history of a genetic condition
Genotypes and Phenotypes • Mom and Dad are Rr-that is their genotype, they can also be described as heterozygous- they have 1 of each gene • What is their PHENOTYPE? • The youngest son has a genotype of rr-he is Homozygous recessive-2 copies of the recessive gene • His phenotype? I can’t Roll my Tongue!
Some common dominant and recessive traits • Widow’s peak is dominant. • You can be homozygous dominant (WW) or heterozygous (Ww) and you will have widow’s peak • What is your genotype and phenotype if you’re homozygous recessive?
Making a Pedigree Chart • Pedigree charts are made to chart family history and see how traits are passed • A genetic counsellor will use pedigree charts to help determine the distribution of a disease in an affected family
Symbols Draw me • Shade individuals that have the trait you’re studying • Boys = squares (Lucy always calls Charlie Brown a ‘block head’) • Girls = circles
Making a Pedigree Chart • Married-connected at side • Siblings-connected at TOP not at the side (hopefully not siblings AND married) • Oldest child-to the left • Question-if shaded individuals in this pedigree have blue eyes, what is the GENOTYPE of the parents?
Other • Divorced, separated • Deceased • Identical twins • Fraternal twins
Organizing the pedigree chart Generations are identified by Roman numerals I II IV
Organizing the pedigree chart • Individuals in each generation are identified by Arabic numerals numbered from the left • Therefore the affected individuals are II 3, IV 2 and IV 3 I II IV 1 2 3 4 5 6 7
What’s going on? Shaded = blue eyes • 1 and 2 split after having 4, 2 then had kids with 3 and split with her too after 5 -9 were born • Genotypes of 1, 4, 7? • Genotypes of 2 & 3? • Genotypes of 5, 6, 8, 9, 10, 11, 12?
