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Exceptions to the Rules Pedigrees Karyotypes Ethics

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Presentation on theme: "Exceptions to the Rules Pedigrees Karyotypes Ethics"— Presentation transcript:

1 Exceptions to the Rules Pedigrees Karyotypes Ethics
Human Heredity Exceptions to the Rules Pedigrees Karyotypes Ethics

2 Examples of Dominant Disorders
Dwarfism Polydactyly and Syndactyly Hypertension Hereditary Edema Chronic Simple Glaucoma – Drainage system for fluid in the eye does not work and pressure builds up, leading to damage of the optic nerve which can result in blindness. Huntington’s Disease – Nervous system degeneration resulting in certain and early death. Onset in middle age. Neurofibromatosis – Benign tumors in skin or deeper Familial Hypercholesterolemia – High blood cholesterol and propensity for heart disease Progeria – Drastic premature aging, rare, die by age 13. Symptoms include limited growth, alopecia, small face and jaw, wrinkled skin, atherosclerosis, and cardiovascular problems but mental development not affected.

3 Examples of Recessive Disorders
Congenital Deafness Diabetes Mellitus Sickle Cell anemia Albinism Phenylketoneuria (PKU) – Inability to break down the amino acid phenylalanine. Requires elimination of this amino acid from the diet or results in serious mental retardation. Galactosemia – enlarged liver, kidney failure, brain and eye damage because can’t digest milk sugar Cystic Fibrosis – affects mucus and sweat glands, thick mucus in lungs and digestive tract that interferes with gas exchange, lethal. Tay Sachs Disease – Nervous system destruction due to lack of enzyme needed to break down lipids necessary for normal brain function. Early onset and common in Ashkenazi Jews; results in blindness, seizures, paralysis, and early death.

4 Exceptions to the Rules

5 Incomplete Dominance The heterozygous is a blend between the dominant and recessive. RR = red rr = white Rr = pink

6 Codominance NS = some of each SS = sickle cells NN = normal cells sick
The heterozygous condition, both alleles are expressed equally Sickle Cell Anemia in Humans NS = some of each SS = sickle cells NN = normal cells sick

7 Polygenic More than one gene contributes to the trait so there can be many phenotypes

8 Multiple Alleles There are more than two alleles for a trait
Blood type in humans Blood Alleles? A, B, O Blood Types? Type A, Type B, Type AB, Type O

9 Rules for Blood Type A and B are codominant
AA = Type A BB = Type B AB = Type AB A and B are dominant over O AO = type A BO = type B OO = type O


11 Chromosomes and Inheritance
Can You see the Number? 4/11/2017 Colorblindness is an X-linked recessive trait. G. Podgorski, Biol 1010

12 Chromosomes and Inheritance
X-linked Chromosomes and Inheritance 4/11/2017 Traits found on the X chromosome G. Podgorski, Biol 1010


14 Pedigrees

15 How to Construct a Pedigree?
A Pedigree is a visual showing the pattern of inheritance for a trait. (Family tree) Symbols and Rules: Male = Female = Affected = Unaffected = Link parents together with a line and then make a vertical line to connect to offspring.

16 Chromosomes and Inheritance
4/11/2017 Is this trait dominant or recessive? Note that the trait can appear in offspring of parents without the trait. G. Podgorski, Biol 1010

17 Chromosomes and Inheritance
Is this trait dominant or recessive? 4/11/2017 Note that the trait appears in every generation and ½ the offspring of an affected heterozygote are expected to show the trait. G. Podgorski, Biol 1010

18 Karyotypes

19 Karyotypes Maps of chromosomes
22 homologous pairs of human chromosomes Sex Chromosomes are the 23rd pair of chromosomes that determine the sex of an individual.

20 Chromosomes and Inheritance
4/11/2017 Changes in Chromosome Number and Structure Down syndrome is caused by a change in chromosome number. G. Podgorski, Biol 1010

21 Chromosomes and Inheritance
4/11/2017 Chromosome Non-Disjunction in Meiosis G. Podgorski, Biol 1010

22 Down syndrome (trisomy 21)

23 Chromosomes and Inheritance
The Frequency of Chromosome Non-Disjunction And Down Syndrome Rises Sharply with Maternal Age 4/11/2017 The phenomenon is clear – the explanation isn’t. G. Podgorski, Biol 1010

24 Chromosomes and Inheritance
4/11/2017 G. Podgorski, Biol 1010

25 Karyotype

26 Karyotype Practice Down Syndrome Male

27 Karyotype Practice Klinefelter Male

28 Turner Syndrome Female
Karyotype Practice Turner Syndrome Female

29 Karyotype Practice XYY Syndrome Male

30 Ethics

31 Chromosomes and Inheritance
4/11/2017 Pre-Implantation Genetic Diagnosis (PGD) Removing a cell for diagnosis from a human embryo. G. Podgorski, Biol 1010

32 Chromosomes and Inheritance
4/11/2017 Amniocentesis and Chorionic Villus Sampling Many new techniques for learning about individual genes rather than whole chromosomes are available or under development. G. Podgorski, Biol 1010

33 If you were to test your DNA…who does it belong to?
12. In the film, a person could have a potential romantic partner sequenced. Discuss the positive and negative aspects of having this technology available to prospective mates.

34 If you were to test your DNA…who does it belong to?
16. You are an employer and know from genetic testing that the most qualified applicant for the job has a 70% chance of developing Multiple Sclerosis in one year's time. Would you hire this person? Why or why not?

35 Gene Therapy

36 p-GLO Gene

37 Choose the sex of your child

38 Picking your Kid’s Traits
14. During a scene in GATTACA, Vincent’s parents visited a doctor who specialized in child conception to select for the best traits for his future brother. They hoped that his brother would have the best possible chances for a successful life. Some of the traits mentioned in GATTACA included intelligence, height and any possibility of inheritable diseases. If you decided to have a child one day and are given the opportunity to select for special traits, would you do so? Explain why or why not.

39 Picking your Kid’s Traits
15. Wouldn't every parent want to ensure that their child was perfect and had the attributes of physical attractiveness, intelligence and athletic prowess to be able to do whatever he or she wanted in life? If so, why is the society portrayed in this film so devoid of happiness, vitality and fun?

40 Chromosomes and Inheritance
4/11/2017 Dolly In 1996, Ian Wilmut cloned Dolly from an adult sheep. Superhuman, by Robert Winston and Lori Oliwenstein p. 97 G. Podgorski, Biol 1010

41 Chromosomes and Inheritance
4/11/2017 CopyCat In February 2002, researchers from Texas A & M reported the live birth of a cloned tabby. Researchers are interested in using cloned cats in AIDS research, since feline AIDS is a good model for human AIDS. Superhuman, by Robert Winston and Lori Oliwenstein p. 97 G. Podgorski, Biol 1010

42 Chromosomes and Inheritance
4/11/2017 Noah Superhuman, by Robert Winston and Lori Oliwenstein p. 97 G. Podgorski, Biol 1010

43 Cloning 18. Cloning is a process in which you make a genetically identical organism. People say that this could be cool others say it is messing with Mother Nature. If you had the opportunity to clone yourself, would you do it and why?

44 Cloning 19. If a couple had a baby who died and could not have any more babies, but had the opportunity to clone their baby, should they be allowed to clone it?

45 Stem Cell Research

46 Stem Cell Research 20. Stem cell research is another ethical issue. Stem cells are cells from an early embryo that can become any type of cell like a heart, lung, liver, or skin cell. The reason people are researching these cells are because you can actually grow new tissues and organs to replace damaged ones. For instance, it may be possible to grow a new set of lungs for someone dying of lung cancer. The ethical issue with this type of research is that in order to get this type of stem cells you have to destroy an embryo so it will never grow into a person. Do you think this research should be done? Why or why not?

47 GATTACA 17. What would you say to a friend who believed themselves to be solely a product of their DNA and with no true freedom?

48 GATTACA 13. The technology to do what was done in the movie is definitely possible within the next fifty years. Do you think that Vincent’s world could eventually happen in America? Why?

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