Human Heredity and Biotechnology Chapter 11.1

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Human Heredity and BiotechnologyChapter 11.1
11.3 with a scattering from Chapter 13
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Recessive Genetic Disorders

• Began with the study of alkaptonuria
• Passed like any recessive trait
• Heterozygous condition results in carriers
• Disorder Table cystic fibrosis albinism
• Disorder Table galactosemia Tay Sachs

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Dominant Genetic Disorders

• Only need one dominant allele to inherit the
  disease
• No carriers
• Disorder Table Huntingtons Disease
  Achondroplasia

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PEDIGREE

• chart which shows the
• inheritance of a trait
• from one generation
• to the next
• Allows geneticists to trace the transmission of a
  trait through a family.
• square male
• circle female
• colored shape has trait
• half colored shape carrier
• slash deceased

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Alexandrina Victoria, born May 1819British
Monarch

• Queen Victoria was a carrier of hemophilia.
• She had nine children and passed hemophilia on to
  several of them.
• All of her children married into the royal
  families of various countries of Europe.
• In this way, all of the Royal Families of Europe
  inherited the gene for hemophilia.

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How many generations are represented?How many
males? afflicted males? normal males?How many
females? afflicted females? normal females?Any
carriers?Sex-linked or autosomal trait?Dominant
or recessive trait?Any twins? deceased
individuals?
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HUMAN CHROMOSOMES

• Humans contain.
• 46 individual chromosomes
• 23 chromosome pairs
• SEX CHROMOSOMES (1 pair)
• determine the sex
• of an individual
• AUTOSOMES (22 pairs)
• do not determine the sex
• of an individual

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KARYOTYPE

• is a photomicrograph
• of the chromosomes
• in a dividing cell
• chromosomes are grouped
• and placed into pairs
• female - 46 XX
• male - 46 XY

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Telomeresprotective caps on ends on
chromosomesmade of protein and DNAmay play a
role in cancer and aging
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Mutations

• Caused by mutagens (anything that may cause a
  mutation)
• Virus, chemicals, toxins, UV light, etc.
• 3 types
• Somatic cell mutations affect body cells
• will affect individual, but not offspring
• Germ cell mutations affect germ cells
• Will affect offspring, but not the individual
• Lethal mutations
• Will cause death either before or shortly after
  birth

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Chromosome Mutations

• Deletion
• A piece of a chromosome is lost
• Inversion
• A piece of a chromosome breaks off, flips over,
  and reattaches
• Translocation
• A piece of a chromosome breaks off and reattaches
  to another chromosome
• Nondisjunction
• Homologues do not separate

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Deletion
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Inversion
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Translocation
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NONDISJUNCTION

• may arise when chromosomes dont separate
• properly during meiosis, this is called
• not coming
  apart

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Nondisjunction

• Leads to either monosomy (45) or trisomy (47) in
  a cell
• Trisomy on 21 Downs Syndrome
• Trisomy on sex chromosomes (23) can lead to XXY
  (Klinefelters syndrome) or XYY
• Monosomy on sex chromosomes (23) can lead to XO
  (Turners Syndrome)

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DOWN SYNDROME(also called trisomy 21)

• male or female having an extra chromosome in pair
  21
• (instead of 2 chromosomes in pair there are 3)
• 
  47 XX or 47 XY

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Nondisjunction on 21 Trisomy 21 (Down
Syndrome)
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TURNER SYNDROME

• female that is missing a sex chromosome
  - 45 XO

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KLINEFELTER SYNDROME

• male having an extra sex chromosome
• 47 XXY or 48 XXXY

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Which mutations are shown?
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Fetal Testing

• Genetic testing for couples with family history
  of genetic diseases
• pre-pregnancy DNA testing genetic counseling
• post-pregnancy PKU testing
• during pregnancy
• Amniocentesis
• Chorionic villi sampling
• Fetal blood sampling

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HUMAN GENOME PROJECT

• Began in 1990 -
• an attempt to sequence
• all of the human DNA.
• Genome an organisms DNA
• Mapping of the human
• genome completed in 2003.

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GENE THERAPY

• process in which an absent or faulty gene is
  replaced by a normal, working gene
• various approaches have been taken
• Bone marrow removed, modified in the laboratory
  and placed back in the body
• Modified viruses have been used to carry
  replacement genes into the body
• Inhalation of genetically engineered viruses
  containing good genes has been attempted
• up to this point, gene therapy has not been very
  successful

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Manipulating DNA

• Today, we have expanded our use of genetic
  information and we are able to use techniques for
  manipulating (modifying) DNA.
• We can.
• extract DNA from cells,
• cut it into small pieces,
• identify the genes and sequences in DNA
• make copies

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Cell Transformation.

• process by which a cell takes in DNA from an
  outside source
• the external DNA may become part
• of the cells DNA

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• Recombinant DNA taking DNA from one organism
  and combining it with another organism
• we have inserted the genes for human insulin and
  human growth hormone into bacteria

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Transgenic Organisman organism containing genes
from another organism

• cow containing genes
• for producing
• human milk proteins

• bacterium containing
• recombinant DNA

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Cloning

• process of producing an identical copy of an
  organism
• we have successfully cloned frogs, salamanders,
  mice, sheep and other organisms

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DOLLY
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• What is genetic engineering?
• it is simply.
• genetic modification
• Throughout the ages,
• man has applied his knowledge
• of genetics to the world around him
• especially to plants and animals.

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Selective Breeding

• the process of breeding animals or plants with
  desired characteristics
• Man has used selective breeding to develop plants
  and animals with desirable traits.
• Nearly all domestic animals dogs, cats, horses,
  and most crop plants have been produced by
  selective breeding.

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Selective Breedingof plants
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Selective Breedingof animals
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Hybridization

• crossing dissimilar individuals to bring together
  the best traits of both organisms
• hybrids (produced by
• such crosses) are
• often healthier and
• hardier than either
• of the parents

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Hybridization
ZEDONK cross between a zebra and a donkey
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Hybridization
LIGER cross between a lion and a tiger
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Hybridization
male DONKEY and female HORSE
MULE Offspring (mules) are
almost always sterile. The mule has greater
endurance, is stronger and less excitable than a
horse.
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Inbreedingcontinued breeding of individuals with
similar characteristics - used to maintain
characteristics in a breed
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Inbreeding
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• While selective breeding often limits variation,
  scientists are also interested in preserving the
  genetic diversity in organisms.
• WHY?
• Genetic diversity (variation) in a population
• can be increased by inducing mutations.
• Mutations may be induced by the
• use of chemicals and radiation.

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