Genetics and Genomics

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Changes in Chromosome Number


Changes in chromosome number, when tolerated, can be an important source of genetic variation and ultimately lead to speciation. However, a change from the normal chromosome number for an individual usually has severe, or even lethal, consequences.

Variation in chromosome number is classified into two main categories of

, which is a change in the number of individual chromosomes, and

, which is a change in the number of chromosome sets.