The 54-year-old academic is the pioneer of the revolutionary crime-fighting technology known as genetic fingerprinting.
Sir Alec, Professor Of Genetics at Leicester University, says,"It is a method of looking at genetic material - DNA - and identifying bits that vary a lot from one person to another, to produce a pattern which is completely individual, specific and inherited.
"The pattern looks a bit like a barcode on supermarket goods and it varies from one person to another quite dramatically.
"A child's fingerprint is made up of a random selection of half of mum's and half of dad', so you can use it not just for identification purposes but also to establish family relationships."
Minute samples of DNA can be found in blood, semen, saliva, hair and skin. Mich like fingerprints, every human being's DNA is unique to them - a fact which has revolutionised forensic science.
Courts throughout the world know that if two DNA samples match, then the odds they come from different people are millions or billions to one against.
More than two million DNA profiles are now held on the UK's National Database alone - and 60 countries, including the United States, use the technique
Sir Alec discovered to combat crime, identify family links in paternity cases and even fight the illegal smuggling of endangered animal species.
In the trials of the Washington snipers last year, an FBI expert testified that DNA evidence from the two accused was found on the rifle and the rifle sight.
On this side of the Atlantic, Sarah Payne's killer, Roy Whiting, was convicted with the help of the technology, as was Soham murderer Ian Huntley.
And further afield, the remains of the last Tsar of Russia and his family were only identified because of Sir Alec's work.
When he first mooted the idea of applying the new technology to criminal investigations, Sir Alec was literally laughed at.
"Now every time you turn the TV on you hear DNA has led to another conviction," he says. "It has impacted on heaven knows how many people in a very direct way. And it did start with me in my lab. I am extremely proud."