Davis’s U-tube experiment

Davis’s U-tube experiment, showing that genetic recombination requires cell-to-cell contact. Auxotrophic bacterial strains Y-10 and 58-161 are unable to grow on minimal medium but produce some prototrophs that grow on minimal medium when they make contact following mixing. Prototrophs are not produced when the auxotrophs are placed in a U-tube, indicating that direct contact is required to generate prototrophic bacteriaDavis’s U-tube experiment, showing that genetic recombination requires cell-to-cell contact. Auxotrophic bacterial strains Y-10 and 58-161 are unable to grow on minimal medium but produce some prototrophs that grow on minimal medium when they make contact following mixing. Prototrophs are not produced when the auxotrophs are placed in a U-tube, indicating that direct contact is required to generate prototrophic bacteria

Alternating suction and pressure Pure culture of Y-10 Pure culture of 58-161 thr' IGU' thi' mett thr+ leu+ thi+ met— Cotton \ ‘\ ,__/ Y-1O 58-161 Glass filter 58-161 No colonies Prototrophic No colonies No colonies No colonies colonies or L—l Control experiments U-tube experiment