Download Notes on Chromosomal Mutations

CHAPTER 10Chromosome
Mutations
REMEMBER THIS FROM CH. 12?
What is a mutation?
 __________________________________________
 There are two types of mutations that can
occur in gamete cells:
 1.
Gene mutation: affect only one gene.
Examples: point and frameshift.
 2.
Chromosomal mutation: affect the
number or structure of chromosomes.
Usually involves many, many genes.

5 TYPES OF CHROMOSOMAL MUTATIONS
1. Deletion
 2. Duplication
 3. Inversion
 4. Translocation
 5. Non-disjunction

DELETION: INVOLVES THE LOSS OF ALL OR
PART OF A CHROMOSOME.

Examples: Cri du Chat syndrome,
Angelman’s syndrome, Prader-Willi
syndrome, Miller-Dieker syndrome
DUPLICATION

Involves the production of extra copies of
parts of the chromosome
Examples: Fragile X syndrome,
Beckwith-Wiedeman syndrome

Inversion: Reverses the direction of parts of
a chromosome.
Translocation: When one part of a
chromosome breaks off and attaches to
another chromosome.
 Example: Edward’s syndrome

NON-DISJUNCTION:
Means “not coming apart”.
 When homologous chromosomes fail to
separate properly during meiosis.

Results in abnormal numbers of
chromosomes. Normal is two of each type of
chromosome.
 Trisomy means a person has an extra copy
of a chromosome.


Monosomy means a person is missing a copy
of a chromosome.


Examples of Trisomy: Down syndrome,
Trisomy 13, Cat eye syndrome (tetrasomy),
Klineflelter’s syndrome (XXY)
Example of Monosomy: Turner’s syndrome