Patent ID: 6962804

Claim:
A method for generating a Drosophila clipped FRT (cFRT) chromosome incapable of reacting with a P transposase but capable of reacting with a yeast site-specific flippase recombinase (FLP), comprising steps of: (a) obtaining a first FRT chromosome by causing a local and random transposition by exposing a FRT chromosome to said P transposase, wherein said FRT chromosome contains a P[FRT] insertion with a selection marker gene; (b) obtaining a second FRT chromosome by screening for said first FRT chromosome lacking said selection marker gene; (c) selecting a third FRT chromosome from said second FRT chromosome by the steps of: (c1) examining both recombination capability and homozygous viability of said second FRT chromosome and selecting said second FRT chromosome having high recombination capability and high homozygous viability; and (c2) examining recombination accessibility of said second FRT chromosome contained in a clipped P[FRT] insertion by the presence of said FLP wherein said third FRT chromosome is selected based on high recombination accessibility; and (d) exposing said third FRT chromosome to said P transposase and obtaining said Drosophila clipped FRT (cFRT) chromosome by said steps (c1) and (c2).