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A eukaryotic gene contains two kinds of base sequences. Exon plays an important role in protein synthesis.
A gene in a eukaryotic organism contains two kinds of nucleotide sequences. They are Exon and Intron. The Exons are expressed nucleotide sequences of a gene and take part in protein synthesis. On the other hand, Introns are intervening nucleotide sequences of a gene and do not take part in protein synthesis.
Both exons and introns are present side by side in a eukaryotic gene. During transcription, RNA polymerase transcribed precursor messenger RNA (pre-mRNA) using both exons and introns sequence. Later, the introns sequences are removed messenger RNA (mRNA) by RNA splicing. Therefore, in the mature mRNA, introns are absent. In the final product, exons are covalently linked to each other to form the mature mRNA.
During translation, this mature mRNA is used by the translational machinery and ribosomes to synthesize protein. Thus, exons sequences play important role in protein synthesis.
The presence of introns or intervening sequences in eukaryotic genes (“split genes”) was first discovered by American geneticist and molecular biologist Phillip Allen Sharp and British biochemist and molecular biologist Richard J. Roberts in 1977. For their discovery of Sharp and Roberts were awarded Nobel Prize in Physiology or Medicine in 1993. American biochemist and Nobel laureate Walter Gilbert first used the term intron.
