Recombinant DNA technology is the science of "cutting and pasting" segments of DNA into new constructs, allowing them to replicate within biological systems and then using them for a specific purpose.
The question that you ask is a HUGE one. I'll just write a bit to help simplify the process for you.
A gene is a length of DNA that typically encodes a protein. Within more complex eukaryotic organisms (such as in mammals), most genes are interspersed with "introns" -- noncoding regions that interrupt the coding regions, or "exons." Generally, recombinant DNA technology involves some forms of cloning -- and cloning doesn't necessarily mean cloning an organism, but fundamentally it means replicating a gene artificially. So, the long length of eukaryotic DNA has to be transcribed into RNA and then that RNA has to have its introns spliced out to form ...
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