Select the examples of how fragile sites can be responsible for phenotypic abnormalities. decreased gene dosage resulting from damage-induced copy loss disruption of tumor suppressor genes causes tumor formation Mendelian autosomal disorders caused by point mutations loss of gene function due to centromere loss increase in gene expression due to duplication Incorrect. At least one of your choices is incorrect. Fragile sites are characterized by nucleotide repeats in the DNA sequence. These repeats cause structural changes or breaks in chromosomes, and both result in a reduction, disruption, or complete loss of gene expression.