Solving the problem of gradient of transfer - gene transfer is based on the distance from the origin, with genes nearest the origin being transferred at the highest frequency, and genes farthest from the origin transferred at the lowest frequency = gradient of transfer INTEGRATION = transfer and recombination A gene must be transferred before it can be integrated into the chromosome. Gradient of transfer means that genes closer to the origin will be transferred and therefore integrated more frequently than genes further from the origin How to remove the gradient of transfer distortion?