Chromosome Mutations

Look at the karyotype for the mutation

A karyotype is an organized profile of a person's chromosomes. In a karyotype, chromosomes are arranged and numbered by size, from largest to smallest.

Karyotypes are done by doctors to diagnose some genetic disorders Ex: Down syndrome, Turner’s syndrome

Karyotypes are done by doctors to diagnose some genetic disorders

A normal human karyotype has 46 chromosomes (23 pairs): #1-22 are called autosomes #23 are called sex chromosomes

XX~ female XY~ male

RECALL…What is a mutation? Any mistake or change in DNA sequence Mutations can only be inherited if they occur in a gamete or sex cells Two types: Gene or chromosomal

Chromosomal mutation: affects whole or part of a chromosome Gene mutation: Changes to the bases in the DNA of ONE gene

Chromosomal Mutations Change in # of chromosomes OR structure of the chromosome Abnormality detected on karyotype Five types

Can YOU spot the chromosomal mutation??

1) Deletion Loss of all or part of a chromosome

2) Duplication Produce extra copies of parts of a chromosome.

3) Inversion Part of a chromosome breaks out and reinserts backwards.

4) Translocation Part of a chromosome breaks off & attaches to another chromosome

5) Nondisjunction Improper separation of homologous chromosomes during meiosis Results in extra or missing chromosomes in gametes

Remember—normally have 2 copies of each Types of Nondisjunction Trisomy~ 3 copies of a chromosome Monosomy~ 1 copy of a chromosome Remember—normally have 2 copies of each

Down Syndrome – Trisomy 21 Intellectual and developmental disabilities may have heart defects and respiratory problems

Trisomy on Sex Chromosomes XYY Syndrome – Extra Y XXX Syndrome – Triple X

Look at the karyotype for the mutation

What is the mutation? Boy or Girl?

What is the mutation? Boy or Girl?

Chromosomal Mutations Videos Visualizing Nondisjunction