Supplementary Table 3: β-diversity vertical adult, genera level from The source of microbial transmission influences niche colonization and microbiome development

Early life microbial colonizers shape and support the immature vertebrate immune system. Microbial colonization relies on the vertical route via parental provisioning and the horizontal route via environmental contribution. Vertical transmission is mostly a maternal trait making it hard to determine the source of microbial colonization in order to gain insight in the establishment of the microbial community during crucial development stages. The evolution of unique male pregnancy in pipefishes and seahorses enables the disentanglement of both horizontal and vertical transmission, but also facilitates the differentiation of maternal versus paternal provisioning ranging from egg development, to male pregnancy and early juvenile development. Using 16s rRNA amplicon sequencing and source-tracker analyses, we revealed how the distinct origins of transmission (maternal, paternal &amp; horizontal) shaped the juvenile internal and external microbiome establishment in the broad-nosed pipefish <i>Syngnathus typhle</i>. Our data suggest that transovarial maternal microbial contribution influences the establishment of the juvenile gut microbiome whereas paternal provisioning mainly shapes the juvenile external microbiome. To pinpoint critical temporal shifts in the early released juvenile microbiome, we were able to identify key microbes with a potential important role in the development of a functioning host–microbe interaction.