 P-element vector

A P-element vector is an engineered DNA carrier that uses P element recognition sequences to introduce cargo into chromosomes when the required P-element transposase is available. The mobile carrier and the enzyme source can be separate. Retaining the needed element ends does a different job from encoding the enzyme that acts on them.^[ref]

In the 1982 transformation study, a P-element vector carrying a wild-type Drosophila melanogaster rosy sequence produced germline transformants with inherited chromosomal copies and restored eye colour. The visible phenotype tested function of the transferred gene, while integration and transmission to descendants provided different evidence about its physical and hereditary fate.^[ref]

For an invented inheritance calculation, assume one autosomal insertion, a heterozygote crossed to an insertion-free animal, and ordinary segregation without viability or transmission distortion. Half the offspring are expected to inherit the insertion. This fraction is conditional on the genetic model; it is not the percentage of injected embryos that will be transformed. A fluorescent or visible signal alone also does not establish a stable single-copy insertion, and an inserted cargo need not express identically at every genomic location.