Final answer:
Chromosome painting involves using fluorescent dyes that bind to DNA, allowing individual chromosomes to be visualized in different colors. This enables geneticists to identify and arrange the chromosomes into a karyotype, which is crucial for detecting chromosomal abnormalities.
Step-by-step explanation:
Individual chromosomes in a technique known as chromosome painting are "painted" using fluorescent dyes that bind to specific sequences of DNA. This creates distinct colors for each chromosome when viewed under a fluorescent microscope. A karyotype is the visual representation of all the chromosomes in a cell, aligned from the largest to the smallest. For human chromosomes, autosomes are ordered from chromosome 1 (the largest) to chromosome 22 (the smallest), with the sex chromosomes (X and Y) depicted separately.
In karyotyping, geneticists first stimulate cells to divide, arrest them in metaphase with colchicine, and use a hypotonic solution to cause the chromosomes to spread apart. The chromosomes are then fixed on a slide, exposed to the fluorescent dyes for painting, and viewed under a microscope to observe their distinct banding patterns and morphology. After imaging, the chromosomes are digitally arranged into the classic karyotype format based on size and centromere position.