Chromosomal aberrations are differences in DNA sequence copy number of chromosome regions 3 . These differences may be crucial genetic events in the development and progression of human cancers. Array Comparative Genomic Hybridization is a laboratory method used in cancer research for the measurement of chromosomal aberrations in tumor genomes. A recurrent aberration at a particular genome location may indicate the presence of a tumor suppressor gene or an oncogene. The goal of the analysis of this type of data includes detection of locations of copy number changes, called breakpoints, and estimate of the values of the copy number value before and after a change. Knowing the exact locations of a breakpoint is important to identify possibly damaged genes. This paper introduces genetic local search algorithms to perform this task.