Fig. 2: Shifts in connectivity biases across Drosophila species.

a, b Principal components were extracted using each connectivity matrix as well as 1000 uniform shuffle (a) or 1000 biased shuffle matrices (b); the fraction of the variance explained by each component was measured (D. melanogaster males: orange; D. melanogaster females: red; D. simulans females: blue; D. sechellia females: green; colors: experimental matrices, gray: shuffle matrices); error bars represent 95% confidence interval. c The Jensen-Shannon distances were measured by comparing the distributions in connectivity frequencies observed experimentally; the color bar denotes the length of the distances measured. See Supplementary Fig. 5 for the complete set of Jensen–Shannon distances. d, e For each glomerulus, the connectivity frequency measured in the D. sechellia matrix was compared to the average connectivity frequency obtained in a set of biased shuffle matrices generated using the generalist matrices, and the probability that a glomerulus being connected to Kenyon cells at a higher (d) or lower (e) frequency in the D. sechellia matrix was measured (p-value); glomeruli were ranked based on p-values and the DL2d, DP1l, DC3 and VM5v projection neurons were further investigated (red). f The p-value measured for each glomerulus was plotted against the log₂ fold change measured when comparing the connectivity frequencies measured for that glomerulus in the two matrices indicated on the plot. The statistical significance, or p-value, was measured for each glomerulus using the Fisher’s exact test; to control for false positives, p-values were adjusted with a false discovery rate of 0.10 using a Benjamini-Hochberg procedure. Within these plots, a fold change with a value of 0 indicates that there is no shift in frequencies between matrices, whereas a fold change that is smaller or greater than 0 indicates that a given glomerulus is connected more frequently in one matrix than the other. Data points with p-values smaller than 0.01 are identified with a label (red); all other data points have p-values greater than 0.01 (black). g A clustering dendrogram based on the connectivity frequencies measured for each glomerulus across species. All source data used in this figure are provided in the Source Data file.