May 15 8:50 a.m. Make Up Exam For only one missed midterm Bring scantron and I.D.

1. May 15 8:50 a.m. Make Up Exam For only one missed midterm Bring scantron and I.D.

3. Sex Determination in Humans http://images.google.com/imgres?imgurl=www.goldenlands.com/Fox%2520network/simpsons/opcs/fullsize/Homer_Marge_opcC1394.jpg&imgrefurl=http://www.goldenlands.com/Fox%2520network/simpsons/simpsonopc.html&h=700&w=694&prev=/images%3Fq%3Dhomer%2Band%2Bmarge%2Bsimpson%26start%3D20%26svnum%3D10%26hl%3Den%26lr%3D%26ie%3DUTF-8%26safe%3Doff%26sa%3DN

4. Sex Determination in Humans – 5 stages Chromosomal Determination Gonad Differentiation Anatomical Differentiation Brain Differentiation Socialization

5. EXAM Chromosomal Sex Determination Humans: 23 pairs of Chromosomes 22 pairs of Autosomes or Somatic Chromosomes (same in both sexes) 1 pair of Sex Chromosomes Males: 1 Y, 1 X = XY Females: 2 X = XX

6. Human Male Karyotype, XY Chromosomes 1-22 are autosomes or somatic chromosomes; non-sex chromosomes XY are the sex chromosomes http://www.amnh.org/learn/musings/FA01/ia/HW_01.jpg

7. Normal Human Female Karyotype; XX 22 pairs of autosomes 1 pair of sex chromosomes, XX

8. X Y

9. Y chromosome has less than 100 genes ……………….. One gene is for ……

10. Additional genes found on Y chromosome Inability to see and hear the obvious gene Inability to express affection over the phone gene Posturing in presence of other males gene Refusal to ask questions when lost gene Channel flipping gene Male Sports Bonding gene Addiction to death and destruction movies gene Preadolescent rock throwing gene Preadolescent attraction to spiders and insects gene Spitting gene X Y

11. EXAM Y chromosome Male anatomy, physiology, behavior SRY (HY) gene SRY (H-Y) protein X chromosome Female anatomy, physiology, behavior w/o SRY (HY) gene

12. Primitive gonad or ovotestes = unspecialized H-Y Gene w/o H-Y Gene Testes ovary Testosterone Estrogens

13. Gonad Differentiation - Male • H-Y or SRY Gene (on Y Chromosome) • H-Y Protein (SRY protein) • Inner part of ovotestes becomes testes • Testes makes male hormones • Male sex organs, • secondary sex characteristics(muscle, skeleton), • Brain development (for constant production of sperm) at 6 weeks

14. Gonad Differentiation – Female • XX • Absence of Y chromosome (no H-Y gene) • Outer ovotestes develops into ovary at about week 12 • Ovary produces female hormones: • ~ sex organs • ~ secondary sexual characteristics (muscle, skeleton) • ~ absence of male hormones at week 6 allows brain to develop menstrual cycle at puberty.

15. Little estrogen Little testosterone Mostly testosterone Mostly Estrogens Female Male

16. Some abnormalities associated with X and Y chromosomes Crossing over of H-Y gene X Y X Y Spermatogenesis H-Y gene H-Y gene crosses over to X chromosome

17. Sperm with X with H-Y gene X X X X Zygote: XX (genetic female) Phenotype = male, because of the H-Y gene Egg with normal X without H-Y gene

18. Sperm with Y without H-Y gene Y Y X X Zygote: XY = genetic male Phenotype = female because of absence of H-Y gene Egg with normal X without H-Y gene

19. EXAM Conclusion: Absence of H-Y gene usually = female; female is automatic unless H-Y gene is present

20. Another Chromosomal Abnormality – Androgen Insensitivity XY Embryo Faulty Processing of testosterone Embryo not conditioned as male Embryo automatically develops into normal looking female Develops into female with XY chromosomes Normal breast development no uterus no oviducts vagina present internal testes present no sperm

21. Primary Oocyte Non-disjunction Secondary Oocyte ovum zygote zygote Extra black chromosome Missing a black chromosome sperm

22. Klinefelter’s Syndrome

23. Klinefelter’s Syndrome – XXY+ 22 pairs of autosomes male with some female characteristics EXAM XX Egg + 22 autosomes Y Sperm + 22 autosomes 1. Normal male until puberty, 2. Testes not normal, 3. Tall, 4. Female musculature, 5. Some breast development, 6. High pitched voice, 7. Usually sterile, 8. XXXY more extreme XXY Zygote + 44 autosomes

25. Trisomy X Syndrome – XXX+ 22 pairs of autosomes female EXAM XX Egg + 22 autosomes X Sperm + 22 autosomes 1. Normal Female, 2, Normal appearance, 3. May be sterile or fertile, 4. May have mental retardation, 5. 1 in 1200 births, 6. XXXX more extreme XXY Zygote + 44 autosomes

26. Turner’s Syndrome = 22 pairs of autosomes and X0

27. Turner’s Syndrome – X0 + 22 pairs of autosomes female EXAM No X Egg + 22 autosomes X Sperm + 22 autosomes • Characteristics: • Normal female until puberty, • Lack of normal ovary development, • sterile • Remain childlike throughout life • Normal intelligence • 1 per 2500 births X0 Zygote + 44 autosomes

29. XYY Syndrome – XYY + 22 pairs of autosomes Male EXAM X Egg + 22 autosomes YY Sperm + 22 autosomes Male Lower than normal intelligence Tall Aggressive – disproven Prison - disproven XYY Zygote + 44 autosomes

30. Early Death Syndrome – Y0 + 22 pairs of autosomes Male ? EXAM No X Egg + 22 autosomes Y Sperm + 22 autosomes Dies as embryo Too many genes missing with X Y0 Zygote + 44 autosomes

31. All chromosomes are capable of forming a trisomy condition. The most common is chromosome 21. Trisomy 21 is also known as Down’s Syndrome

32. Trisomy 21 – Down’s Syndrome 3 chromosome #21 Results in physical defects and mental retardation Frequency increases with mother’s age Why? Prophase I occurs before birth, Anaphase I occurs 12-50 years later More ionizing radiation picked up in older woman’s lifetime resulting in nondisjuctions All chromosomes can have trisomy

33. Primary Oocyte Non-disjunction 21 21 Secondary Oocyte 21 21 21 21 21 21 ovum 21 21 21 zygote 21 zygote 21 Extra black chromosome Missing a black chromosome sperm

34. In Trisomy 21, chromosomes 21 do not separate after crossover Younger women 21 21 Older women

35. EXAM Trisomy 21 increases with Mother’s age

37. Triploid (3N) male karyotype – individual appeared normal except for slightly smaller lower jaw. This person also has Klinefelter, XXY

39. Triploid Watermelon - seedless Triploid carp - sterile

40. Barr Body inactivates one of the X chromosomes in XX cells after embryo is properly developed sexually http://www.mun.ca/biology/scarr/Barr_Bodies.jpg

41. XGreen XPink XX zygote Mitosis XG XP XG XP Mitosis Mitosis Active XG cell line Active XP cell line Female mosaic

42. XGreen XGreen XX zygote Mitosis XG XG XG XG Mitosis Mitosis Active XG cell line Active XG cell line Female all green

43. Anhidrotic Ectodermal Dysplasia: N = dominant, normal allele on X chromosome n = recessive allele carried on X chromosome resulting in no teeth and no sweat glands XNXN normal female XnXn female with few or no teeth and no sweat glands XNXn female parts of jaw with teeth and parts without teeth parts of skin with sweat glands, parts without sweat glands. XNY normal male XnY male with no teeth and no sweat glands

44. No teeth, no sweat glands XNXn female http://www.bitein.com/images/reshma02.jpg

45. Calico Cats (normally all females) B = allele for black fur, on X chromosome O = allele for orange fur, on X chromosome XBXB All black fur, female cat XOXO All orange fur, female cat XBXO Black and orange, female cat (Calico) XBY Black, male cat XOY Orange, male cat XBXOY Black and orange, male (Klinefelter, Calico) XBXO

46. Conclusion – always one fewer Barr Body than X chromosomes EXAM

47. Notice that two of the X chromosomes have Barr bodies causing them to be inactive