DNA Analysis

Question

What is a restriction endonuclease, describe how these can be used to investigate two types of polymorphism found in DNA?

 

Answer 1

Hi Sam,

 

Restriction endonuclease is an an enzyme that works on/cuts nucleic acids, such as DNA and RNA. There are many different types of endonucleases such as single stranded endonuclease, double stranded endonuclease, DNA or RNA endonucleases and so on.

 

Restriction endonuclease implies to the enzyme whose activity is defined by a specific site on DNA (usually, there could be some exceptions). Examples include EcoR1, BamH1, Acc 1, Pvu II, Hindi 3 and so on. All these enzymes nick and cut  DNA on their specific sites, if enzyme has one site then it would simply linearize circular DNA of small genome/plasmid.  Multiple sites as well as combination of enzymes will produce number of large and small fragments.   

 

DNA polymorphism implies to the phenomenon when nucleotide sequence of genomic DNA of a species is altered but its protein coding sequence remains same. Alteration of nucleotide sequence would alter the sites for restriction

enzymes and there single or double digestion with specific enzyme would show an altered pattern indicating polymorphism.

 

Hope this helps.