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Molecular Biology Review module of the MLA course on Introduction to Molecular Biology Information Resources
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Chromosomal Mutations

Mutations can occur at the level of a chromosome, through chromosomal breakage:

 
 

Deletion: loss of a piece of DNA from a chromosome. Deletion of a gene or part of a gene can lead to a disease or abnormality.

Duplication: production of one or more copies of any piece of DNA, including a gene or even an entire chromosome.

Insertion: a type of chromosomal abnormality in which a DNA sequence is inserted into a gene, disrupting the normal structure and function of that gene.

Translocation: breakage and removal of a large segment of DNA from one chromosome, followed by the segment's attachment to a different chromosome.

Sources:  image from the National Human Genome Research Institute (NHGRI) Genetic Illustrations; definitions from the National Human Genome Research Institute (NHGRI) Glossary of Genetic Terms

Molecular Biology Review
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Revised 11/01/2007