Karyotypes & Pedigrees

Karyotypes A chart or picture of a person’s chromosomes

Why are karyotypes performed? To check for aneuploidies (the condition of an abnormal number of chromosomes) Some common aneuploidies: –Turner syndrome: the presence of a single X chromosome (genotype = XO) –Klinefelter syndrome: the presence of an extra X chromosome (genotype = XXY) –XYY Male: presence of an extra Y (genotype = XYY) –Downs syndrome: presence of extra 21 st chromosome

Using karyotypes to help people with genetic disorders Genetic counseling – can range from support group to sessions with a specialist to discuss treatment Prevention - parents could check to see if these types of genetic disorders could be passed on to their children

Pedigrees A tool used to show the pattern of inheritance of a trait in a family

Pedigree symbols = Normal Male = Affected Male = Normal Female = Affected Female = Carrier Female

Reading a pedigree The Roman numerals on the side represent the generation The # under the square/circle represents each person (#’ed from L to R, starting at 1 for each generation) Used to find a certain individual on the pedigree

How is this trait passed on?