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:
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
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
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!