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AP. Biology essay The finding of the Introns and the exons was one of the most significant discoveries in genetics in the past fifteen years. split genes were discovered when lack of relation between DNA sequences were seen during. DNA- mRNA hybridation. For all ....

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.... finishes transcription, the Poly A tail is added to the 3¹ end. As the two ends are placed the mRNA becomes pre-mRNA. The pre-mRNA consists of splicing and non-coding regions. pre-mRNA molecules are much longer than the mRNA molecule needed to code for its protein. The regions that do not code for amino acids; aa, are scattered all along the coding region. The genes are split with coding regions, called exons, short for expressed regions; in between the exons the non-coding region called introns exist. Before the translation of mRNA the introns must be spliced off. Splicing is an complicated process for the cell. It must locate every intron i ....