The smallest portion of DNA that can be isolated using this method comprises 10 million base pairs - hundreds or thousands of individual genes.
They are able to identify each chromosome based on its unique pattern of dark and light bands.
Or, a portion of a chromosome may be repeated over and over again, resulting in an unusually wide, dark band (known as a homogeneously staining region).
To understand more about what causes these conditions, scientists hope to determine which genes and DNA sequences are located near these unusual bands.
The researcher next produces multiple copies of the isolated DNA using a procedure called PCR (polymerase chain reaction).