What is a Karyotype?

1
What is a Karyotype?

• Honors Biology
• Monkemeier/ Germinario

2
Karyotype

• Pronunciation Carry o type
• Also Known As chromosome test, chromosome
  analysis
• A karyotype is a picture of all the chromosomes
  from an individuals cells. A karyotype is a test
  used to check for chromosome abnormalities

3
What does a Karyotype Look Like?
4
How is a Karyotype made?

• A picture of a persons chromosomes is created by
• staining the chromosomes with a special dye,
• photographing them through a microscope and
• arranging them in pairs from longest to shortest.

5
What information can be obtained by analyzing a
karyotype?

• A karyotype gives information about the number of
  chromosomes a person has, the structure of their
  chromosomes and the sex of the individual.

6
Abnormalities on Karyotype Chromosome Numbers

• Monosomy Mono one Somy body
• Monosomy Only one chromosome is found on the
  line in the karyotype where a pair of chromosomes
  should be found.

7
Monosomy

• Monosomy 13

• Monosomy 23 or Turners Syndrome

8
Trisomy One chromosome too many on a line where
a pair of chromosomes is expected.
9
Abnormalities in Chromosome Numbers - Common

• Down syndrome (trisomy 21)
• Patau syndrome (trisomy 13) serious eye, brain,
  circulatory defects as well as cleft palate.
  15000 live births. Children rarely live more
  than a few months.
• Edward's syndrome (trisomy 18) almost every
  organ system affected 110,000 live births.
  Children with full Trisomy 18 generally do not
  live more than a few months.

10
Abnormal Number of Chromosomes

• Klinefelter syndrome 47, XXY males. Male sex
  organs unusually small testes, sterile. Breast
  enlargement and other feminine body
  characteristics. Normal intelligence.
• 47, XYY males Individuals are somewhat taller
  than average and often have below normal
  intelligence. At one time (1970s), it was
  thought that these men were likely to be
  criminally aggressive, but this hypothesis did
  NOT stand up to testing and has been disproven
  over time.

11
Abnormal Number of Chromosomes

• Trisomy X 47, XXX females. 11000 live births -
  healthy and fertile - usually cannot be
  distinguished from normal female except by
  karyotype
• Monosomy X (Turner's syndrome) 15000 live
  births the only viable monosomy in humans -
  women with Turner's have only 45 chromosomes!!!
  XO individuals are genetically female, however,
  they do not mature sexually during puberty and
  are sterile. Short stature and normal
  intelligence. (98 of these fetuses die before
  birth)

12
Karyotypes also show abnormal chromosomes.

• Crit du Chat is a disorder shown on a karyotype.
  Note that one of the chromosomes on pair number 5
  is missing a piece.