2 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 cellsT/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
6 Sex-Linked DisordersHow would a person inherit a sex-linked disorder?
7 Sex-Linked DisordersY chromosome does not carry all of the genes of an X chromosomeFemales 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
8 Sex-Linked DisordersBecause 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 itMen only need ONEColorblindness – inability to distinguish between red/greenHemophilia - Prevents blood from clotting – even small cuts can be fatal
26 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?
27 Recessive vs. Sex-Linked What is the difference between recessive traits and sex-linked traits?How does this change the pedigree chart?
28 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 itMen only need ONEMen…Do NOT have a back up X chromosomeIf Mom is carrying the gene, men have a chance of suffering from the disease!