The generation of a pig model of cystic fibrosis (CF) is a multistep process. Initial steps in this process involved the design and cloning of a small DNA fragment (SDF) or large oligodeoxynucleotide (LODN) that contains the F508del mutation and a silent restriction fragment length polymorphism causing mutation. This SDF/LODN was transfected into wild-type (WT) pig fetal fibroblast with the intention of modifying the pig genomic DNA by small fragment homologous replacement (SFHR). The targeted deletion (F508del) was detected in a subpopulation of transfected cells by allele-specific polymerase chain reaction (AS-PCR).