SNP
SNP is an acronym of ‘single–nucleotide polymorphism’. It might sound technical, but what this means is relatively simple. A SNP is a variation in a DNA sequence. It is a DNA molecule that ‘doesn't fit’ typically in a DNA pattern.
To explain SNP more fully, though, we need to think about the words which it is made up of: single-nucleotide polymorphism. Breaking it down, nucleotide is a fancy term for a DNA molecule and when lots of nucleotides (or DNA molecules) are joined together you get a string of DNA. So, the ‘single’ in SNP means ‘just one’, the nucleotide in SNP means ‘DNA molecule’ and polymorphism refers to any rare genetic predisposition such as a rare blood group or an allergy. In a SNP there is one DNA molecule out of place in a string of DNA, breaking the pattern.
For example, if you are comparing two samples of DNA from different people who seem to be related you might see that one person has a sequence such as: AGGCTTA and another person has a similar sequence of AGACTTA, the third ‘G’ in the first sequence is replaced with an ‘A’ in the second. That specific nucleotide (the ‘G’ in the first), which is marks a difference between the two sequences is a SNP.
It can be useful to look at SNPs in people’s DNA code to figure out if they might have certain medical problems such as lactose intolerance or sickle cell anaemia – both of which show up as SNPs. Variations in DNA patterns can also help in deciding what the best treatment would be for specific illnesses and diseases.
