Presentation on theme: "Pedigree Charts Day 103. DN 103 T/F Every chromosome is different between a man and a woman T/F Men and women have different numbers of chromosomes in."— Presentation transcript:
Pedigree Charts Day 103
DN 103 T/F Every chromosome is different between a man and a woman T/F Men and women have different numbers of chromosomes in their sex cells T/F If you looked in a cell during mitosis and you could see the chromosomes lining up, you could tell whether the cell belonged to a man or a woman
Review Female Male Meiosis Sex Cell Mitosis
In lions, (A) is the allele for dark eyes and (a) is the allele for light eyes. Female Aa Male Aa Meiosis Sex Cell (A) Sex Cell (a)
Sex-Linked Disorders How would a person inherit a sex-linked disorder?
Sex-Linked Disorders Y chromosome does not carry all of the genes of an X chromosome Females have two X chromosomes, so they carry two copies of each gene found on the X – backup! Genes for certain disorders are carried on X chromosome
Sex-Linked Disorders Because the gene for these is recessive, and men only have 1 X chromosome, men are more likely to have sex-linked disorders (if they have the gene, they will express it – diseases like this are called HEMIZYGOUS) Women need two copies of the gene to express it – Men only need ONE Colorblindness – inability to distinguish between red/green Hemophilia - Prevents blood from clotting – even small cuts can be fatal
Let’s make a pedigree chart!
Pedigree Charts Women are represented by circles Men are represented by squares/rectangles
Pedigree Charts When they get married…
Pedigree Charts When they have babies…
Pedigree Charts How many daughters did they have? How many sons did they have? Was their oldest child a son or a daughter?
Pedigree Charts What happens when the children get married?
Let’s PRACTICE on the Briggs Family Alicia married Drew…
Briggs Family And they have three children, Chelsea, John and Daniel
Briggs Family Daniel marries a lovely girl named Anna…
Briggs Family … and they have two daughters, Jocelyn and Stephanie…
Briggs Family Stephanie marries a man who loves and respects her, named Jeff…
Briggs Family … and they have three children, Nick, Caroline and Michael
Disaster strikes the Briggs Family OOOOOHHH NOOOOOOOO! Alicia and Drew were both carriers of a recessive disease…
Briggs Family Chelsea has the disease, Daniel is a carrier…
Briggs Family Whew! Anna is not a carrier! Can Daniel and Anna pass the disease on to their children?
Briggs Family Ruh roh… Stephanie and Jocelyn both carry the disease.
Briggs Family Bad luck… Jeff is a carrier…
Briggs Family DISASTER Nick and Caroline both suffer from the disease. Assuming Michael gets married to someone who doesn’t have the disease, and is not a carrier, can his children get the disease?
Recessive vs. Sex-Linked What is the difference between recessive traits and sex-linked traits? How does this change the pedigree chart?
Recessive vs. Sex-Linked If a trait is carried on the X chromosome, women are carriers. They have a back-up X chromosome in case of a mutation. Remember: – Women need two copies of the gene to express it – Men only need ONE Men… – Do NOT have a back up X chromosome – If Mom is carrying the gene, men have a chance of suffering from the disease!
ES 103 Draw a pedigree chart (different from the one we did in class), showing family members that passed down a disease through three or more generations.