Reannealing shows three distinct steps: highly repeated fraction. Short sequences that repeat themselves over and over without interruption. Spread out at random: use a technique called fish to figure it out i. e. fluorescence in situ hybridization. Biotin binds very strongly to avidin: we can make gfp-fusion proteins: fluorescent-avidin. Treat slide with hot salt solution to denature. Incubate with biotinylated dna probe: then wash to remove unhybridized. Incubate with fluorescently labeled avidin to reveal location of bound, labeled dna probe: counterstain chromosomes so they appear red. Highly repetitive dna found in centromeres of chromosomes: moderately repeated fraction. Present as a single copy per haploid set of chromosomes. Localized to a particular site on a particular chromosome. Eukaryotic dna is not a simple progression of gene after gene. Produced most often by unequal crossing over: slide 10/55. Can lead to the evolution of multigene families. Leads to family of genes that each have a specialized function.