Figure 7From: Darcin: a male pheromone that stimulates female memory and sexual attraction to an individual male's odourFemale sexual attraction to male urine is elicited by darcin. Total time spent under test male stimulus (blue bars: male urine; cyan bars: recombinant major urinary protein (MUP) alone; hatched bars: male urine plus recombinant MUP) and matched control stimulus (pink bars: BALB/c female urine; open bar: buffer), together with the difference in time spent under test minus control (circles), plotted as means ± standard error of mean. Significant P values indicate greater attraction to the test male stimulus [matched pair t-tests of log transformed data (t)]. Control tests using intact urine from C57BL/6 strain [B6, A(a)] or a random selection of n = 14 wild males [Wild, B(f)] confirmed greater attraction to male urine. No attraction was shown towards BALB/c male urine [Bc, B(g)] which contained an extremely low level of darcin. Recombinant darcin (r-darcin, 11 μg) stimulated significant attraction when presented alone [A(b,c)] and when added to male BALB/c urine [B(h)]. There was no attraction to other recombinant MUPs (r-18694Da; r-18645Da). SDS-PAGE of urine stimuli (C), equivalent to one-thirtieth of the amount used in behavioural tests. The different mobility of r-darcin relative to native darcin is a consequence of the C-terminal His-tag used for purification (see Additional File 1: Figure S4).Back to article page