R.J.Robert and P.A. Sharp (1977) discovered split genes (gene with introns) in eukaryotes for which they were awarded Noble Prize in 1993. Split genes, present in eukaryotes have coding gene which are not continuous, but are interrupted by noncoding sequence. There are two kinds of alternating segments in the split genes - exon and intron. Exon contains coding nucleotides sequences which are ultimately translated into· polypeptides. They carry genetic information. Intron contains non-coding nucleotide sequences which are not translated into polypeptides. Eukaryotic genes without introns are called exonic "genes (non split genes), e.g., histone gene, interferon gene.