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  1. 1. Heredity<br />
  2. 2. The passing on of certain inherited characteristics from one generation to another.<br />1. What is heredity?<br />
  3. 3. Hair<br />Eyes<br />Height<br />Intelligence<br />Talents<br />Dimples<br />2. Name 3 characteristics that can be hereditary.<br />
  4. 4. Defective gene from one or both parents<br />Downs Syndrome<br />Hemophilia<br />Muscular Dystrophy<br />Sickle Cell Anemia<br />Cleft Palate<br />Cystic Fibrosis<br />Spina bifida<br />Hereditary Birth Defect<br />
  5. 5. 46 chromosomes carry thousands of genes.<br />Contain all the characteristics a person will have.<br />3. What is the relationship between chromosomes and genes?<br />
  6. 6. Males have XY chromosomes<br />Females have XX chromosomes<br />Egg and Sperm cells have only 23 chromosomes<br />All eggs are X, sperm can be X or Y<br />Sperm cell from father determines sex of baby<br />4. How is the sex of the child determined?<br />
  7. 7. Sex Determination<br />
  8. 8. Chromosome: Threadlike particles in nucleus of cell which carries hereditary factors.<br />Genes: Part of the chromosome that determines all inherited characteristics<br />5. Terms to Define<br />
  9. 9. Dominant: Stronger gene that determines appearance of a trait.<br />Recessive: Weaker gene; will not appear when paired with a dominant gene<br />
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  11. 11. 6. At the moment of conception, every human baby receive 46 tiny chromosomes. 23 from the sperm/father, 23 from the egg of the mother.<br />7. At Conception: the fertilized egg has instantly acquired all the physical traits its parents can ever give it.<br />
  12. 12. Dominant & Recessive Gene Combinations for Eye Color<br />Brown-eyed Blue-eyed<br />
  13. 13. A. Identical twins: 1 egg + 1 sperm -- splits into two children, must be the same sex.<br />B. Fraternal Twins: 2 eggs + 2 sperm –both fertilized; can be same sex or one of each.<br />C. Siamese Twins: Conjoined twins – 1 egg + 1 sperm split, however the split does not completely occur.<br />8. Explain how the following occur:<br />
  14. 14. Identical Twins:<br />One fertilized egg splits in half, each half develops into a separate embryo. <br />Happens soon after fertilization<br />Offspring share DNA, they are the same sex<br />ONE EGG, ONE SPERM, ONE PLACENTA<br />Fraternal Twins:<br />Two eggs are released at same time, each fertilized by different sperm.<br />No more alike genetically than any siblings<br />TWO EGGS, TWO SPERM, TWO PLACENTAS<br />Multiple Births….<br />
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  16. 16. ONE EGG, ONE SPERM<br />EGG STARTS TO SPLIT AS IN IDENTICAL TWINS, BUT DOESN’T COMPLETE THE SPLIT.<br />EMBYROS WILL DEVELOP ATTACHED<br />can be extremely traumatic <br />approximately 40-60% of these births are delivered stillborn with 35% surviving just one day. <br />overall survival rate between 5-25%<br />historical records over the past 500 years detail about 600 surviving sets of conjoined twins with more than 70% of those surviving pairs resulting in female twins.<br />CONJOINED TWINS<br />
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  19. 19. Eng and Chang Bunker, The Siamese Twins <br />There is an extremely rare form of identical twins that occurs perhaps in one out of every 75,000 to 100,000 births or 1 in 200 deliveries of identical twins, that of conjoined twins.Conjoined twins originate from a single fertilized egg so they are always identical and same-sex twins. The developing embryo starts to split into identical twins within the first two weeks after conception but then stops before completion, leaving a partially separated egg which continues to mature into a conjoined fetus. <br />The most famous set of conjoined twins were Chang and Eng, the men who originated the term "Siamese Twins". Eng and Chang were born in Siam (modern day Thailand) on May 11, 1811 to a Chinese father and half-Chinese, half-Malay mother. Thanks to their heritage, while growing up in Siam the boys were known as "The Chinese Twins".Despite the fact that their birth was initially believed to be an omen of the end of the world, they brought celebrity to their small village. Their mother refused to allow doctors to attempt to separate the boys, fearing that to do so would result in the death of one or both. Instead she taught them to stretch the tissue that joined them so that they could stand side-by-side rather than always face-to-face.<br />
  20. 20. Chang and Eng began to date Adelaide and Sarah Ann Yates, two of nine daughters of local farmer and part-time clergyman, David Yates. The townspeople disapproved, so Chang and Eng scheduled a separation surgery in Philadelphia. Their fiancées found out and quickly stopped the proceeding, and in April, 1843, Chang was married to Adelaide and Eng to Sarah Ann in a double wedding.    <br />During the course of their marriages, Eng fathered six boys and five girls; Chang seven girls and three boys. All were normal except for a son and daughter of Chang's who were deaf mutes.<br />In January, 1874, Chang Bunker died after a severe case of bronchitis, possibly from a cerebral clot. Eng died shortly thereafter. <br />After their deaths it was determined they could have been successfully separated, a medical option that was never offered to Eng and Chang during their lives.<br />
  21. 21. Although Eng and Chang's fame helped coin the phrase 'Siamese Twins', they were not the first pair of conjoined twins recorded in medical annals as there were probably about 100 such pairs known by the time of their 1811 births, a fact which helped the King of Siam reverse an early death sentence on the brothers. In fact, conjoined twins were recorded as early as 945 in Armenia and the first pair of successfully separated twins took place in 1689 by German physician G. König.<br />The birth of two connected babies can be extremely traumatic and approximately 40-60% of these births are delivered stillborn with 35% surviving just one day. The overall survival rate of conjoined twins is somewhere between 5-25% and historical records over the past 500 years detail about 600 surviving sets of conjoined twins with more than 70% of those surviving pairs resulting in female twins.<br />
  22. 22. How common are twins and other multiple pregnancies?These days, about one in 32 births are twin births. This rate has gone up 65 percent since 1980, and it's more than double the rate among women who conceive without medical assistance — one in 89.The rise in triplets and quadruplets is even more dramatic. Between 1980 and 1998, the rate of triplets and higher-order multiple births shot up by more than 400 percent, but it's crept back down over the past few years as fertility treatments have become more refined. In 2003, one in 535 births resulted in triplets, quadruplets, or more.Meanwhile, the likelihood of having identical twins (when one fertilized egg divides in half) is about one in 250. This rate hasn't changed over the decades and is remarkably constant all over the world.<br />
  23. 23. 9. What is the relationship between infertility and fertility analysis?<br />Infertility: Problems of conception or implantation have occurred<br />Fertility Analysis: What options does a couple have<br />
  24. 24. Fertility Drugs<br />Artificial Insemination – Sperm is injected into woman's uterus.<br />IVF (Invitro-Fertilization) – Sperm and egg are fertilized outside of body and then placed in the uterus – Test tube baby – very expensive with only a 80-90% chance of pregnancy. Variation: Ovum transfer<br />Surrogate Mother: Carries fertilized egg through IVF for couple or may be artificially insemination by father’s sperm<br />Adoption<br />1o. List 5 options for an infertile couple<br />
  25. 25. An abnormality that affects the structure or function of the body.<br />Hereditary & Environmental<br />11. What is a Birth Defect?<br />
  26. 26. Any pregnancy that ends due to natural causes before the embryo/fetus could possibly survive on its own.<br />20% of pregnancies end in miscarriage<br />After 20 weeks, known as a stillbirth<br />12. What is a miscarriage?<br />
  27. 27. Anything affecting the fetus by what the mother has done while pregnant; poor nutrition, alcohol, drugs, x-rays etc.<br />13. Environmental Birth Defect<br />
  28. 28. Downs Syndrome: 21st chromosome pair has 3 chromosomes instead of usual 2<br />15. Birth Defect caused by an error in chromosomes<br />
  29. 29. Mother and baby have different blood types;<br />Example: Mother RH -, Father RH +, = Baby RH+ <br />Mother will have an RH different from her own after labor and delivery and her body will begin to make antibodies to fight of this “intruder”<br />Next baby is rejected by mothers immune system.<br />16. Explain what RH Incompatibility is.<br />
  30. 30. Informs parents in advance the odds that their children will have a certain disease.<br />Parents suspect a problem from:<br />Medical/Family History<br />Physical Exam<br />Lab Tests<br />17. How can a genetic counselor help prospective parents?<br />
  31. 31. Amniocentesis: Needle inserted through belly button withdraws amniotic fluid; Recommended for women over 35.<br />Ultra Sound – Sound waves make an image to insure fetus is developing normally.<br />Chorionic Villi Sampling: Catheter goes through vagina into uterus for sample of tissue from membrane encasing fetus; Can find out results much sooner that amniocentesis.<br />18. List and explain 3 genetic tests for diagnosing birth defects.<br />
  32. 32. 19. Environmental Hazards to avoid during pregnancy and explain their potential dangers.<br />Alcohol – FAS, Women should not have any amount<br />Over the Counter Medications: Aspirin, Ibuprofen etc. May cause problems for baby<br />Caffeine: Coffee, tea, sodas, chocolate; <br />Tobacco: Premature & Low birth weight<br />Illegal Drugs: Serious addictions and brain damage<br />X-rays: Radiation; make sure to tell Doctor or Tech.<br />Rubella or German Measles: Vaccine now<br />STD’s : Birth defects or blindness etc.<br />Other Infections: Should always discuss with doctor.<br />
  33. 33. Addiction passed on to fetus<br />Prematurity and low birth weight<br />Withdrawal – painful and may even cause death<br />Birth defects <br />Learning Disorders<br />20. Explain how the use of drugs could affect the development of the fetus during pregnancy<br />
  34. 34. END<br />