GCD 3022 Lecture Notes - Lecture 1: Copy-Number Variation, Comparative Genomic Hybridization, Mutation
9 Mar 2018
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Document Summary
Among different species, natural variation exists with regard to chromosome structure and number. Three features of chromosomes that aid in their identification are centromere location, size, and banding patterns. Within a species, variations in chromosome structure include deletions, duplications, inversions, and translocations. Chromosome breaks can create terminal and interstitial deletions. Some deletions are associated with human genetic disorders such as cri-du-chat syndrome. Nonallelic homologous recombination creates gene duplications and deletions. Over time, gene duplications can lead to the formation of gene families, such as the globin gene family. Copy number variation (cnv) is fairly common within a species. Comparative genomic hybridization is one technique for detecting chromosome deletions and duplications. It is used in the analysis of cancer cells. In an inversion heterozygote, crossing over within the inversion loop creates deletions and duplications in the resulting chromosomes. Two mechanisms that may produce translocations are (1) chromosome breakage with subsequent repair and (2) nonhomologous crossing over.
