Figure 4.

Relative abundances of bacterial taxa in egg and embryonic samples of the great tit (A) before excluding potentially contaminating Ralstonia and cross-contaminating Enterococcus for both protocols (P1 and P2) and (B) and after their exclusion for P1 only. Only the most abundant genera (relative abundance > 1%) are shown. Less abundant genera are included in the category ‘Other’. Results are shown for different amplification protocols (P1 and P2, see the section ‘Methods’ for more details). E0-egg—egg content sample at embryonic day 0, E13-nat—E13 intestinal sample from nonmanipulated egg, E13-Ent—E13 intestinal sample from an Enterococcus-treated egg, E13-PBS—E13 intestinal sample from a control PBS-injected egg, F—female faecal samples (amplified by P1 only). For the relative abundances in P2 after Ralstonia and Enterococcus exclusion, see Figures S1 and S5 (SI1). High-resolution images of Fig. 4(A) and (B) with individual sample IDs can be found in Supplementary Information 5(A) and (B), respectively.