Small changes to chromosomes can cause major phenotypic effects. Chromosomes mutate through deletion, duplication, inversion, or translocation of genes. A karyotype examines chromosomes under a microscope to identify any mutations by analyzing chromosome number, size, shape, centromere position, and banding pattern.

1. Chromosome
Mutations
and
Karyotypes
Laboratory Biology
Class Notes

2. Chromosome Mutations
Even small changes in
chromosomes can cause major
phenotypic changes
Mutations are spontaneous and can
happen at any time
Genes can change in 4 ways
Deletion
Duplication
Inversion
Translocation

3. Types of Mutations
Deletion:gene or genes are removed
from the chromosome
Duplication:gene or genes are
doubled on the same chromosome

4. Types of Mutations
Inversion:gene or genes switch
positions, usually between arms of
the chromosomes
Translocation:gene or genes switch
positions between chromosomes

5. Discovering Mutations
Chromosomes can be
examined for any
mutations
Chromosomes are
prepared and viewed
under a microscope
Stained chromosomes
are arranged in pairs in
order

6. Karyotypes
A karyotype is a
prepared display of
chromosomes
Geneticists look at:
the number of
chromosomes
the size and shape of
the chromosomes
the position of the
centromere
the banding pattern of
the genes