Describe mechanisms by which new genes could arise.

Exon shuffling.

Explanation:

Exon shuffling may be defined as the phenomena of in which genes are exchanged between the different exons. Types of exon shuffling are transposon shuffling and cross over at the time of gamete formation.

Exon shuffling is responsible for the formation of new genes. Different exons combine together to form the new genes. The duplication of exons also leads to the formation of new genes. The intron-exons structure is altered for the new gene formation.

Thus, the correct answer is exon shuffling.