Transcript Karyotype - Ms. Fuller's Biology Class

GENETIC DISORDERS
Unit 5
What is a Karotype?
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A picture of the collection of
chromosomes found in an
individual’s cells
Tells you the chromosome
number of an organism
 46 in humans
Tells you the sex of an
organism
 XX = Female XY = Male
Can indicate whether or not
a chromosomal abnormality
is present.
Karyotype
MALE
FEMALE
Chromosomal Mutations
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Inversion
 A segment of a chromosome breaks off, flips, and reattaches
Duplication
 An entire gene segment is repeated
Non Disjunction
 Caused by the failure of chromosomes separating during meiosis
 Typically classified as either monosomy or trisomy.
Translocation
 When a section of one chromosome attaches to another chromosome
Deletion
 When a section of a chromosome is deleted
Common Chromosomal Abnormalities
Monosomy

the condition in which a
diploid cell is missing a
chromosome
Trisomy
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the condition in which a
diploid cell has an extra
chromosome
Down Syndrome
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Down Syndrome/Trisomy 21
 Extra 21st Chromosome
 Trisomy /Normally a non
disjunction, can be a
translocation.
 Symptoms:
▪ Distinctive shaped eyes
▪ Cognitive heart
abnormalities
▪ Simian folds
▪ Below average cognitive
ability
Down Syndrome
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Down’s caused by a
translocation.
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Down’s caused by a non
disjunction
Turner’s Syndrome
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Turner’s Symdrome
1
X chromosome and
no match (XO)
 Monosomy
 Only females
 Symptoms
 Short
stature, Webbed
neck, Broad chest,
Non-functioning
ovaries, sterility
Klienfelter’s Syndrome
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Klienfelter’s Syndrome
 2 X chromosomes and 1 Y
 Trisomy (XXY)
 Only in males
▪ Symptoms
▪ Underdeveloped male
sex characteristics
▪ Reduced fertility
▪ Slightly feminime
characteristics
▪ Potential language
impariment
Edward’s Syndrome
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Edward’s Syndrome/Trisomy 18
 Caused by non-disjunction
(trisomy)of the 18th chromosome.
 Symptoms:
 Clenched hands
 Feet with a rounded bottom
 Low birth weight
 Mental delay
 Poorly developed fingernails
 Small head (microcephaly)
Cri du chat
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Cri du chat
 Also called “call of the cat”,
chromosome 5p deletion
syndrome or Lejeune’s
syndrome.
 Caused by a deletion of
part of chromosome 5
 1:50,000 live births, slightly
more common in girls.
 Symptoms:
 Cognitive delays, unique
facial features, unique cry
Common Gene Mutation
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Not detectable on a karyotype
 Sickle
Cell Anemia
 Tay-Sachs Disease
 Cystic Fibrosis
Sickle Cell Anemia
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Sickle Cell
 Caused by a point
mutation within the protein
that makes hemoglobin.
 Thought to have evolved
as a defense against
malaria
 Symptoms:
 Anemia, Fatigue,
Infection
Tay Sachs Disease
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Tay Sachs Disease
Point mutation causing
the body to lack a
critical protein that
breaks down chemicals
in nerve tissue
 Symptoms
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Deafness, Blindness,
Seizures, Demintia
No treatments
 Children usually die
before age 5
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Cystic Fibrosis
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Cystic Fibrosis
 Most common mutation is a
deletion (frame shift
mutation) of 3 nucleotides
on chromosome 7 resulting
in the loss of the amino
acid phenylalanine
 Symptoms
 Thick mucus secretions,
and frequent chest
infections, trouble
digesting food.