1. Chapter 8

2. SWBAT … Analyze positive and negatives of genetic testing.

3. Risks and Benefits of Knowing Your Genetic Makeup

4.  Does your answer change if you couldn’t treat the disease?  Does your answer change if your age was different?  Does your answer change if you could pass the disease to your child? 4

5. A human has 46 chromosomes Genes are found on chromosomes Genes have multiple forms (EX: blue eyes vs. brown eyes) Some genes are hidden in a person, but can be passed to their offspring.

6. Chromosomal Ex. Down Syndrome, Turner Syndrome Single Gene Ex. Sickle Cell Anemia, Cystic Fibrosis Complex Ex. Birth defects, most cancers

7. 1. Carrier 2. Prenatal 3. Newborn

8.  Testing prospective parents.  A blood sample or cheek cell sample is analyzed to determine whether either parent carries a gene for disease/disorder.  Parents may decide to have prenatal testing on the fetus.

9.  This can detect a disorder before a baby is born.  An ultrasound test is used to determine if the fetus is at a high or low risk from a genetic disorder.  Disorders are diagnosed by examining a small amount of fetal cells. This carries a small risk to the fetus.  If diagnosed early in the pregnancy, there is still the possibility of abortion.  Prenatal screening is sometimes seen as controversial.

10.  Diagnosis chromosome abnormalities Concerns  Pain to mother  Could cause Infection  Could cause miscarriage

11.  Diagnosis chromosome abnormalities and certain genetic defects Concerns  Miscarriage risk  Infection risk  Risk of newborn limb defects

12.  Diagnosis chromosome abnormality  Checks for fetal blood problems  Checks for oxygen level in blood  Medication can be given before birth Concerns  Bleeding at sample site  Risk of infection  Amniotic fluid might leak  Risk of fetal death

13.  Immediate diagnosis & treatment  A blood sample is tested for genetic disorders.  In most of the USA, newborn screening is mandatory, unless parents have a religious objection to it.

15.  Study entire chromosome set of person.  Chromosomes are stained during metaphase to mark the identical bands. You can see two identical homologous chromosomes during metaphase.

18.  During anaphase, chromosomes separate to opposite poled of the cell.  If sister chromatids do not separate, one cell will get an extra chromosome and one will not get a chromosome.  Three copies of a chromosome is called trisomy. Example: Down Syndrome  One copy of a chromosome is called monosomy. Example: Turner Syndrome

19.  Trisomy 21 (extra chromosome 21)  Leads to distinctive facial features, short stature, heart defects, and mental disabilities  Frequency in United States is 1 in 800  Trisomy 21 risk increases with mothers age

22. Diagnosis Reduce testing Appropriate intervention (prevention, management, treatment) Informed decisions Reproductive choices

23. Risk of miscarriage Psychological impact Family relations Insurance issues/concerns Privacy

24. by Nancy A. Rice, Department of Biology, Western Kentucky University, and Bruno Borsari, Biology Department, Winona State University 24

25.  Abby is 20 years old and has been having abdominal pain.  An ultrasound has indicated a mass on her right ovary. 25

26. 26

27.  Simplest definition From the American Cancer Society “ cancer is a group of diseases characterized by uncontrolled growth and spread of abnormal cells. If the spread is not controlled, it can result in death.”  Tumor ◦ Two types:  Benign (non-cancerous) – this is not cancer!  Does not spread; it can eventually become malignant in some cases.  Malignant (cancerous) – this is cancer!  Has the potential to spread to other parts of body. 27

28. 28 Role of Cell Division in Cancer Top = normal cell division Bottom = unregulated cell division and tumor formation Malignant If tumor invades surrounding tissue (cancerous) Metastatic If individual cells break away and start a new tumor elsewhere (cancerous) Benign If tumor has no effect on surrounding tissue (non-cancerous) Image from the National Cancer Institute

29. 29 A.Cyst B.Cancer

30. 30 Ovarian adenocarcinoma (malignant) Ovary cystoadenoma (benign) Normal ovarian epithelium

31. Abby had already learned a lot about ovarian cancer so she followed Dr. Allen’s explanation. “I’m only 20 years old. How did I get ovarian cancer? Isn’t this a disease of older women? “Typically ovarian cancer does affect older women. However, you may have a genetic predisposition for it. Cancer cells have mutations in specific genes that regulate cell division. When they are mutated, cell division becomes uncontrollable,” the doctor explained. 31

32. “I learned about those genes on the Internet! Is it true that some ovarian cancers are associated with mutated copies of genes called BRCA1 or BRCA2?” asked Abby. “Yes,” said Dr. Allen. “You likely were born with one a mutated copy of these genes already. A mutation of the second copy could have occurred more recently, triggering the development of your tumor.” 32

33.  Cancer arises from the accumulation of genetic changes (mutations).  Most cancers have a minimum of 6-9 different genes mutated.  Not a hereditary disease – we do not pass on cancer to offspring.  We can inherit dispositions (susceptibility) to cancer.  Many genes that are mutated in cancer are involved in regulating the cell cycle (checkpoints). 33

34.  Two gap or growth phases (G1 and G2)  S phase - DNA synthesis  M phase - Mitosis 34 Interphase

35. One common chemotherapy for ovarian cancer is Taxol, which was first isolated from Yew bark in 1962 by the National Cancer Institutes (NCI). Taxol blocks a cell's ability to break down the mitotic spindle during mitosis. With the spindle still in place, the cell can't divide into daughter cells and therefore the cancer can’t grow. 35 Taxus Brevifolia

36. 36 Abby’s ovarian cancer has been in remission for 10 years. She graduated from college with a BA in Anthropology. Three years later she married, and today she is living happily with her husband Charles and their four-year-old adopted daughter.

37.  Protective caps on the ends of chromosomes  Found to be related to aging and cancer https://www.youtube.com/watch?v=rUuO1sL3pwY 2 minutes