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Pedigree Charts

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Title: Unit 04 Part III Author: Cris Robson Last modified by: Jasmine Mellado Created Date: 6/10/2004 5:41:26 PM Document presentation format: On-screen ... – PowerPoint PPT presentation

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Title: Pedigree Charts


1
Pedigree Charts
  • The family tree of genetics

2
Pedigree Charts
I
II
III
3
Overview
  • What is a pedigree?
  • Definition
  • Uses
  • Constructing a pedigree
  • Symbols
  • Connecting the symbols
  • Interpreting a pedigree

4
What is a Pedigree?
  • A pedigree is a chart of the genetic history of
    family over several generations.
  • Scientists or a genetic counselor would find out
    about your family history and make this chart to
    analyze.

5
Constructing a Pedigree
  • Female
  • Male

6
Connecting Pedigree Symbols
Examples of connected symbols
  • Fraternal twins
  • Identical twins

7
Connecting Pedigree Symbols
Examples of connected symbols
  • Married Couple
  • Siblings

8
Example
  • What does a pedigree chart look like?

9
Symbols in a Pedigree Chart
  • Affected
  • X-linked
  • Autosomal carrier
  • Deceased

10
Interpreting a Pedigree Chart
  • Determine if the pedigree chart shows an
    autosomal or X-linked disease.
  • If most of the males in the pedigree are affected
    the disorder is X-linked
  • If it is a 50/50 ratio between men and women the
    disorder is autosomal.

11
Example of Pedigree Charts
  • Is it Autosomal or X-linked?

12
Answer
  • Autosomal

13
Interpreting a Pedigree Chart
  • Determine whether the disorder is dominant or
    recessive.
  • If the disorder is dominant, one of the parents
    must have the disorder.
  • If the disorder is recessive, neither parent has
    to have the disorder because they can be
    heterozygous.

14
Example of Pedigree Charts
  • Dominant or Recessive?

15
Answer
  • Dominant

16
Example of Pedigree Charts
  • Dominant or Recessive?

17
Answer
  • Recessive

https//www.youtube.com/watch?vIr1t9awmUl4
18
Summary
  • Pedigrees are family trees that explain your
    genetic history.
  • Pedigrees are used to find out the probability of
    a child having a disorder in a particular family.
  • To begin to interpret a pedigree, determine if
    the disease or condition is autosomal or X-linked
    and dominant or recessive.

19
Pedigree Chart -Cystic Fibrosis
https//www.youtube.com/watch?vWuk0W10EveU
20
Human Genetics
21
Karyotype
22
Chromosome Number
Homologous Chromosomes are the sets of each pair
  • Different for different species
  • Full set 2NDiploid
  • N
  • pairs
  • 1 pair from mother
  • 1 pair from father
  • Humans 23 pairs or
  • 46 total

23
Autosomes Sex Chromosomes
Autosomes 1-22 for all traits except sex
Sex chromosomes Pair 23 XX(female)
or XY(male)
24
Down Syndrome 3 of 21
25
Klinefelters XXY
26
Mutation
A to A G C
A T GC
  • Change in DNA code
  • Caused by
  • Chemical damage
  • Errors in Replication
  • X-ray damage
  • UV damage

X
27
Mutation
  • Changes in the DNA code
  • Changes in the final proteins made
  • Changes in the organism

28
Mutations
  • Chromosome mutations involve changes in the
    structure of a chromosome or the loss or gain of
    a chromosome.
  • There are three types of chromosome mutations
  • 1. deletion the loss of a piece of a chromosome
    due to breakage.
  • 2. inversion a chromosomal segment breaks off,
    flips around backward and then re-attaches.
  • 3. translocation a piece of one chromosome
    breaks off and re attaches to a non-homologous
    chromosome.

29
(No Transcript)
30
Genetic Technology
  • Recombinant DNA
  • Bacterial Transformation

31
1. Mice that glow???
https//www.youtube.com/watch?vk7-ofCWJiUg
32
2. Genetic Engineering
  • Altering the genetic makeup of an organism
  • By Cutting DNA from one organism and inserting
    fragments into a host
  • Recombinant DNA
  • Alters the allele frequency of a population by
    artificial means

33
Recombinant DNA
  • Recombine
  • Connecting or reconnecting DNA fragments
  • DNA of two different organisms
  • Example lab of inserting human DNA into bacteria

34
Genetic Engineering of Insulin
Human DNA cut out
Human DNA put into bacteria DNA
Many Bacteria Grow human insulin
Bacteria DNA is opened up
35
4. Transgenic Organism
  • trans across
  • genic race
  • Contains genes from another organism
  • Bacteria
  • Virus
  • Human

36
5. Tobacco Recombinant DNA Process
  • Isolated DNA to be inserted into host
  • Attach DNA fragment to a vehicle (vector)
  • Transfer the vector to the host
  • Transgenic organisms

37
Restriction Enzymes
Bacterium DNA cut
Human Cut
Restriction Enzymes cut DNA at very specific
sites Separate the base pairs of both
strands Scissors in Recombinant DNA
38
Vectors vehicles
  • Carry foreign DNA fragments into the host
  • Bacteria carried the firefly DNA into the tobacco
    cells
  • Biological or
  • Mechanical

39
Vectors
  • Biological
  • Virus
  • Bacterial plasmid (circular DNA)
  • Mechanical
  • Micropipette
  • Metal bullet coated with DNA

https//www.youtube.com/watch?vnfC689ElUVk
40
Recombinant DNA Uses
  • Grow human hormones in bacteria cultures
  • Artificial sweeteners using bacteria to make
    amino acids
  • Study human diseases by inserting human DNA into
    mice
  • Replace incorrect DNA sequences
  • Replace harmful bacteria on plants
  • Nitrogen bacteria in the soil plants to make
    fertilizer
  • Improve transport of fruits
  • Resist diseases
  • Increase protein production

41
Genetic engineering and Gene therapy Right or
wrong?
  • Genetic engineering is one of the
  • fastest growing medical sciences.
  • There are 2 types of cell and so 2 types of
  • gene therapy
  • Somatic cells found in the body
  • Germ-line - cells found in sperm and eggs
  • (hereditary)

42
Somatic Cell Therapy
  • This is when a gene is introduced into a
  • patient to help them recover from a
  • disease.
  • It could be used to help those suffering
  • from cystic fibrosis.
  • Only the patient is affected and so there
  • are few ethical concerns.

43
Germ Line Therapy
  • Changes are made to genes that will
  • affect subsequent generations.
  • We do not know the consequences of this.
  • It will affect what it means to be human.
  • We take charge of our own evolution.

44
The many uses of Genetic Engineering
  • To repair a genetic defect.
  • To enhance a natural effect e.g. growth.
  • To increase crop resistance to disease or
    climate.
  • To test and screen for genetically inherited
    diseases.
  • To cure disease by altering the genes.
  • To select human genes embryo selection
    (designer babies)

45
Embryo Selectionas a form of Genetic Engineering
Designer babies or a cure for genetically
inherited diseases? To select the sex of a child
or to create a healthy baby to cure a sick
sibling?
46
  • Embryo Selection is a relatively simple process.
    An ovarian biopsy can yield many eggs which can
    be fertilized in vitro with the partners sperm.
    The cells can be grown in culture, and at the
    eight cell stage, one of the cells can be removed
    for diagnosis.

47
Embryo Selection
  • To the right is a picture of a glass micropipette
    used to remove the cell for diagnosis. The width
    of the pipette opening is one cell wide.

48
  • How is it done?
  • The removal of one cell allows DNA tests to be
    performed on the embryo. The embryo with the
    desired trait can then be selected.
  • The final step is implanting the embryo into the
    uterus, and letting the pregnancy continue to
    term.
  • This process is called in vitro fertilization.

49
Embryo selection is being done for certain select
conditions, like cystic fibrosis, Huntingtons
disease, and sickle cell anaemia.
50
Questions raised by embryo selection
  • What are the specifics of embryo selection, is
    there a limit?
  • What are the benefits and consequences of embryo
    selection?
  • What is the difference between embryo selection
    and genetic engineering?

51
Questions raised by embryo selection
  • Is embryo selection ethical?
  • Is it ethical to choose the sex of your baby?
  • Is it ethical to choose the characteristics of
    your baby?
  • Is it ethical to rid your baby of diseases
    through this process?
  • What is done with the embryos that are not
    selected?
  • How do you store and dispose of the unused
    embryos?

52
What are the specifics of embryo selection, is
there a limit?
  • Bioethicists generally find current practices of
    embryo selection not too problematic, because the
    elimination of debilitating diseases justifies
    the intrusion. However, if embryo selection can
    be used to select deleterious traits, why
    couldnt it be used to select for other
    enhancing traits. Here bioethicists begin to
    find the procedure more problematic because it
    takes on eugenic nature.

53
What are the benefits and consequences of embryo
selection?
  • Benefits
  • Many embryos are implanted back into the woman
    (greater chance of pregnancy)
  • Child is without disease
  • Other embryos can be cultured and frozen so they
    can be used again

54
What are the benefits and consequences of embryo
selection?
  • Consequences
  • Goes against nature
  • Very expensive
  • Not 100 guaranteed
  • Not available to all women

55
Is Embryo Selection Ethical?
  • Some would say
  • Embryo selection is ethical when
  • looking for syndromes/diseases which later would
    cause the child to die within the first few
    years,
  • would cause severe retardation,
  • cases which would be a better choice than
    abortion, and to avoid emotional stress.
  • Embryo selection is not ethical when
  • choosing specific sex,
  • choosing character traits,
  • killing discarded embryos.

56
Issues for Ethics
  • Personhood the morality of discarding an embryo
    when it is considered a person.
  • The right to life what is done with spare
    embryos.
  • The right to a child.

57
Ethical Approaches4. Virtue Ethics
  • The virtue of compassion is important when
    considering those suffering from genetic
    diseases.
  • But it is also important to consider compassion
    to the embryos, so it could be argued both ways.

https//www.youtube.com/watch?vdKBfxoPnT7g
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