<unk>  is a molecular mechanism for the formation of new genes. It is a process through which two or more exons from different genes can be brought together ectopically, or the same exon can be duplicated, to create a new exon-intron structure. There are different mechanisms through which<unk>  occurs: transposon mediated<unk> , crossover during sexual recombination of parental genomes and illegitimate recombination.<unk>  follows certain splice frame rules. Introns can interrupt the reading frame of a gene by inserting a sequence between two consecutive codons (phase 0 introns), between the first and second nucleotide of a codon (phase 1 introns), or between the second and third nucleotide of a codon (phase 2 introns). Additionally exons can be classified into nine different groups based on the phase of the flanking introns (symmetrical: 0-0, 1-1, 2-2 and asymmetrical: 0–1, 0–2, 1–0, 1–2, etc.) Symmetric exons are the only ones that can be inserted into introns, undergo duplication, or be deleted without changing the reading frame.
Exon shuffling
Osseoincorporation
Exon skipping
Fusion transcript
Gene duplication
Fusion gene
Copy number variation
Insertion sequence