ANNOUNCEMENTS. Homework Quiz: Take out your HW Take a sheet of scrap paper Put your name and per. # on it Content quiz on Fri - Pedigrees Field Trip to the Field Museum next Monday!. Period 3 HW Quiz. Draw the proper shape with correct shading for the following:
A sample, advanced pedigree
What we will go over today:
Sample pedigree - Cystic fibrosis
Generations are designated
by Roman Numerals and
numbered from top to bottom.
Individuals in each generation
are given standard numbers
Starting from left to right.
What type of inheritance pattern does Cystic fibrosis follow?
What clues does the pedigree give you?
It is autosomal recessive.
Only 2 individuals w/ trait
Parents do not exhibit
Autosomal recessive diseases in humans
Clues for identifying autosomal dominant pattern
Trait is common in the pedigree
Trait is found in every generation
Affected individuals transmit the trait to about 1/2 of their children
Individuals of both sexes affected equally
Autosomal dominant traits
ex. achondroplasia (a sketelal disorder causing dwarfism)
Clues for identifying X-linked recessive inheritance
X-linked recessive traits
ex. Hemophilia in European royalty
Pedigree Analysis in real life
Why do all this?
Rules for determining genotype:
What is the pattern of inheritance?
What are IV-2’s odds of being a carrier?
Remember – determining genotypes will help!
Start with what you can quickly determine and
work your way around until you fill in the missing pieces.
What does the double line represent?
For these 2 individuals to have the trait when the parents do not,
will this be a dominant or recessive trait?
Sample pedigree - cystic fibrosis
What can we say about the genotype of I-1 and I-2?
What can we say about the genotype of II-4 and II-5?
What is the chance that III-5 is a carrier?
Make a punnett square w/ 2 heterozygous parents
What is the inheritance pattern?
What is the genotype of III-1, III-2, and III-3?
Could IV-5 possibly pass the trait on to their son?
III1 = XNY, III2 = XNXn, III3 = XNY
III-1 has 12 kids with an unaffected wife
8 sons - 1 affected
4 daughters - 2 affected
Does he have reason to be concerned about paternity?