Genetic Profiling
Take, for example, a Woman who has a relative with Downs syndrome. She knows that in her DNA there is the gene for Downs syndrome and that there is a chance she could carry it. Before she gets pregnant with her partner she might want to find out if both her partner and herself carry the gene and what the chances are of her child also being born with the condition.
The first step in obtaining this information is to go through genetic profiling. Firstly she would need to give a DNA sample (usually using a sterilized cotton swab rubbed against her inner cheek, or alternatively a blood sample) which is then sent to a laboratory and is analysed using one of several different methods (for example STR analysis which uses either gel or capillary electrophoresis to extract and multiply the relevant DNA strands). From the information which this tests provide a DNA profile can be generated and compared to the genetic information of others or to the regional haplotype (typical or 'universal' genetic information used as a reference) to find any gene mutations, irregularities and of course similarities between relatives.
Genetic profiling is used in a huge range of situations, from crime scene investigation to determining maternal and paternal relationships. It is carried out on a huge scale, with genetic information held securely in DNA banks for use at later dates. While the keeping of genetic profiles within these banks is controversial (some claim that it is in violation of basic human rights to anonymity and is a step towards a totalitarian society), some argue that the lives of some patients can be saved if their relatives' DNA profiles are available to test and to indicate the likelihood of an individual carrying a gene for a specific condition.