Diagnosing Genetic Disorders
• Years ago Dr.’s relied on pedigrees and punnett squares to help predict whether a child might have a genetic disorder
• Today doctors use tools such as amniocentesis and karyotypes to help determine genetic disorders.
• Amniocentesis­a long needle is inserted into the mother’s belly to remove a small amount of fluid that surrounds the developing baby…why?
• Because cells from the baby will be found there and then they use that to make a karyotype
1
Karyotype
• karyotype­ a picture of all the chromosomes in a cell
• arranged in pairs by length and location of the centromeres • Reveals whether a baby has the right number of chromosomes (would show genetic disorders)
• you can also tell whether it is a boy/girl 2
Karyotyping Activity
Diagnosis…analyzing karyotypes and determining the sex and the disease.
3
Genetic Counseling
• A couple with a concern about genetic disorders may turn to a genetic counselor for advice.
• Age­related
• Family history
• Genetic counselors might run tests to see if the parents are carriers for a particular genetic disorder.
4
Pedigrees
• To study patterns of inheritance in humans you would need to trace the inheritance of traits through many generations in a number of families
• An important tool that geneticists use to trace the inheritance of traits in humans is a pedigree
• Pedigree­ a chart or “family tree” that tracks which members of a family have a particular trait.
• You can use pedigrees for any kind of trait…including sex­linked.
5
6
7
8
9