Section 1 of 6
The Method
A profile is made in five operations, and each of them replaced something slower. The entries here follow the method from a membrane and a film through to a list of integers a register can search.
Entries in this section
How a profile is actually produced. 6 entries.
- Entry 1.01The Southern blotThe original approach transferred separated fragments to a membrane and probed them, and it needed a large, fresh sample and days of work.
- Entry 1.02Multilocus probesThe first probes read many sites at once and produced a barcode-like pattern that was powerful for identity and very hard to interpret in a mixture.
- Entry 1.03PCR and the single locusAmplification changed the requirement completely: enough copies could be made from a very small starting amount to read one site at a time reliably.
- Entry 1.04STR multiplexesShort repeated sequences at many sites, amplified together in one reaction, are what every modern profile and every national database is built on.
- Entry 1.05Capillary electrophoresisFragments are separated by size in a thin capillary and detected by fluorescence as they pass a window.
- Entry 1.06What a profile isA profile is a list of numbers at named sites — not a picture, not a sequence, and not a person.
Other sections
Every entry on the site is reachable from the whole register.