2. AP Biology 2006-2007 Genetic Disorders

3. AP Biology Chromosomal abnormalities  Incorrect number of chromosomes  nondisjunction  chromosomes don’t separate properly during meiosis  breakage of chromosomes  deletion  duplication  inversion  translocation

4. AP Biology Nondisjunction  Problems with meiotic spindle cause errors in daughter cells  homologous chromosomes do not separate properly during Meiosis 1  sister chromatids fail to separate during Meiosis 2  too many or too few chromosomes 2n n n n-1 n+1

5. AP Biology Alteration of chromosome number

6. AP Biology trisomy 2n+1 Nondisjunction  Baby has wrong chromosome number  trisomy  cells have 3 copies of a chromosome  monosomy  cells have only 1 copy of a chromosome n+1n monosomy 2n-1 n-1n

7. AP Biology Human chromosome disorders  High frequency in humans  most embryos are spontaneously aborted  alterations are too disastrous  developmental problems result from biochemical imbalance  imbalance in regulatory molecules?  Certain conditions are tolerated  upset the balance less = survivable  characteristic set of symptoms = syndrome

8. AP Biology Box #1  What are two causes of nondisjunction?  What is the outcome?

9. AP Biology Down syndrome  Trisomy 21  3 copies of chromosome 21  1 in 700 children born in U.S.  Chromosome 21 is the smallest human chromosome  but still severe effects  Frequency of Down syndrome correlates with the age of the mother

10. AP Biology Down syndrome & age of mother Mother’s age Incidence of Down Syndrome Under 30<1 in 1000 301 in 900 351 in 400 361 in 300 371 in 230 381 in 180 391 in 135 401 in 105 421 in 60 441 in 35 461 in 20 481 in 16 491 in 12 Rate of miscarriage due to amniocentesis:  1970s data 0.5%, or 1 in 200 pregnancies  2006 data <0.1%, or 1 in 1600 pregnancies

11. AP Biology Genetic testing  Amniocentesis in 2nd trimester  sample of embryo cells  stain & photograph chromosomes  Analysis of karyotype

12. AP Biology Sex chromosomes abnormalities  Human development more tolerant of wrong numbers in sex chromosome  But produces a variety of distinct syndromes in humans  XXY = Klinefelter’s syndrome male  XXX = Trisomy X female  XYY = Jacob’s syndrome male  XO = Turner syndrome female

13. AP Biology  XXY male  one in every 2000 live births  have male sex organs, but are sterile  feminine characteristics  some breast development  lack of facial hair  tall  normal intelligence Klinefelter’s syndrome

14. AP Biology Klinefelter’s syndrome

15. AP Biology Jacob’s syndrome male  XYY Males  1 in 1000 live male births  extra Y chromosome  slightly taller than average  more active  normal intelligence, slight learning disabilities  delayed emotional immaturity  normal sexual development

16. AP Biology Trisomy X  XXX  1 in every 2000 live births  produces healthy females  Why?  Barr bodies  all but one X chromosome is inactivated

17. AP Biology Turner syndrome  Monosomy X or X0  1 in every 5000 births  varied degree of effects  webbed neck  short stature  sterile

18. AP Biology Box #2  Describe two types of sex chromosome abnormalities

19. AP Biology Changes in chromosome structure  deletion  loss of a chromosomal segment  duplication  repeat a segment  inversion  reverses a segment  translocation  move segment from one chromosome to another error of replication error of crossing over

20. AP Biology Certain human genetic disorders can be attributed to the inheritance of single gene traits or chromosomal changes.

21. AP Biology Sickle cell anemia is a hereditary blood disorder caused by a single nucleotide substitution that results in abnormally shaped hemoglobin. Fatigue Rapid heart rate Strokes Painful joints Delayed growth Fatigue Rapid heart rate Strokes Painful joints Delayed growth

22. AP Biology Sickle cell disease is more common in those of African descent, due to heterozygote advantage. (People who are heterozygous for sickle cell have less chance of acquiring malaria.) H A H A Normal blood cells H A H S Heterozygote; less likely to get malaria H S H S Sickle cell disease

23. AP Biology Box #3  What are the advantages and disadvantages of the sickle cell trait

24. AP Biology Huntington’s disease is an autosomal dominant disorder that causes degeneration of the nervous system. Affected individuals usually begin showing symptoms at 35-40. Hallucinations Psychosis Dementia Jerking movements Confusion Rigidity Death Hallucinations Psychosis Dementia Jerking movements Confusion Rigidity Death

25. AP Biology Color blindness is caused by a sex-linked recessive mutation. Because of this, males are twice as likely to inherit this trait as females. Trouble seeing colors and the brightness of colors. Trouble differentiating between shades of the same color or similar colors. Trouble seeing colors and the brightness of colors. Trouble differentiating between shades of the same color or similar colors.

26. AP Biology

27. Tay-Sachs disease is an autosomal recessive disorder of the nervous system, more prevalent in the Ashkenazi Jewish population. Deafness Blindness Dementia Eventual paralysis Seizures Death, usually before age 4 or 5. Deafness Blindness Dementia Eventual paralysis Seizures Death, usually before age 4 or 5. Cherry-red spot

28. AP Biology Many ethical, social and medical issues surround human genetic disorders. Genetic screening for Tay-Sachs

29. AP Biology Ethical Considerations of Genetics Testing:  Possible discrimination by employers or health insurers  The need for ethical standards for work with human research subjects or tissues  Consideration of social, cultural and religious perspectives on genetics and health  Marketing of genetics tests  Informed consent  Possible discrimination by employers or health insurers  The need for ethical standards for work with human research subjects or tissues  Consideration of social, cultural and religious perspectives on genetics and health  Marketing of genetics tests  Informed consent

30. AP Biology Box #4  Describe your stance on genetic testing.

31. AP Biology The Human Genome Project sequenced the entire human genome.  An international collaboration between hundreds of labs in the United States, the UK, Japan, France, Germany and Spain.  Began in 1990; completed in 2000.  Mostly funded by the US Department of Energy, National Institute of Health and private interest groups.  An international collaboration between hundreds of labs in the United States, the UK, Japan, France, Germany and Spain.  Began in 1990; completed in 2000.  Mostly funded by the US Department of Energy, National Institute of Health and private interest groups.

32. AP Biology The Human Genome Project can help us understand diseases by: Genotyping of specific viruses to direct appropriate treatment  Identification of oncogenes and mutations linked to different forms of cancer  The design of medication and more accurate prediction of their effects  Advancement in forensics  Biofuels and other energy applications;  agriculture,  Comparative sequencing to establish evolutionary relationships (such as BLAST)  The commercial development of genomics research related to DNA based products (a multibillion dollar industry). Genotyping of specific viruses to direct appropriate treatment  Identification of oncogenes and mutations linked to different forms of cancer  The design of medication and more accurate prediction of their effects  Advancement in forensics  Biofuels and other energy applications;  agriculture,  Comparative sequencing to establish evolutionary relationships (such as BLAST)  The commercial development of genomics research related to DNA based products (a multibillion dollar industry).

33. AP Biology Box #5  Describe the purpose of the human genome project.

34. AP Biology Historical Ethical, Legal, and Social Issues (ELSI) of Genetics Eugenics advocates improving human hereditary traits through selective reproduction of more desired people and traits, and reduced reproduction of less desired people and traits. Eugenics advocates improving human hereditary traits through selective reproduction of more desired people and traits, and reduced reproduction of less desired people and traits.

35. AP Biology Sterilization Laws were practiced by many states during the 1900s.  Compulsory sterilization of mental health patients  Men sterilized to treat aggression and criminal behavior  Coerced sterilization of many ethnic groups  The American eugenics movement was the model for Nazi eugenics policies.  Compulsory sterilization of mental health patients  Men sterilized to treat aggression and criminal behavior  Coerced sterilization of many ethnic groups  The American eugenics movement was the model for Nazi eugenics policies.

36. AP Biology Amniocentesis is a medical procedure used in prenatal diagnosis of chromosomal abnormalities. A small amount of amniotic fluid, which contains fetal tissues, is sampled and the fetal DNA is examined for genetic abnormalities. The test is usually performed between the 15 th – 20 th week of pregnancy.

37. AP Biology Amniocentesis can lead to Selective Reduction of Multiple Embryos Nadya Suleman, known as Octomom in the media, is an American woman who came to international attention when she gave birth to octuplets in January 2009. Suleman octuplets are only the second full set of octuplets to be born alive in the United States. The circumstances of their high order multiple birth have led to controversy in the field of assisted reproductive technology as well as an investigation by the Medical Board of California of the fertility specialist involved.

38. AP Biology Actress Angelia Jolie made the headlines when she underwent a prophylactic mastectomy after finding out that she was genetically predisposed to breast cancer.

39. AP Biology The Genetic Information Nondiscrimination Act of 2008, also referred to as GINA, is a new federal law that protects Americans from being treated unfairly because of differences in their DNA that may affect their health. The new law prevents discrimination from health insurers and employers. The Genetic Information Nondiscrimination Act (GINA)

40. AP Biology Can a gene be patented? Not according to the US Supreme Court. In Association for Molecular Pathology vs. Myriad Genetics, Inc., the Supreme Court ruled that a natural gene cannot be patented. However, synthetic genes, such as cDNA are patentable. (June 2013)

41. AP Biology Box # 6  Do you agree with the supreme courts decision? Explain

42. AP Biology 2006-2007 Don’t hide… Ask Questions!!