Most of the eukaryotic genes are mosaIc(嵌合体), consisting of intervening sequences separating the coding sequence Exons(外显子): the coding sequences Introns(内含子): the intervening sequences RNA splicing: the process by which introns are removed from the pre mRNA Alternative splicing〔可变剪接):some pre-mRNAs can be spliced in more than one way, generating alternative mRNAS. 60%o of the human genes are spliced in this manner.Most of the eukaryotic genes are mosaic (嵌合体), consisting of intervening sequences separating the coding sequence ◼ Exons (外显子): the coding sequences ◼ Introns (内含子) : the intervening sequences ◼ RNA splicing: the process by which introns are removed from the pre￾mRNA. ◼ Alternative splicing (可变剪接): some pre-mRNAs can be spliced in more than one way , generating alternative mRNAs. 60% of the human genes are spliced in this manner