When stained with the Giemsa dye, human mitotic chromosomes display a characteristic pattern of light and dark 'bands'. The human karyotype contains ~2000 G-dark bands that are visible in high resolution metaphase spreads. If the haploid human genome contains 3 billion base pairs and encodes ~30,000 genes, roughly how many genes would be removed by a DNA deletion that could be detected by karyotypic analysis?