Variations in Daphnia pulex host-associated bacteria by host phylogenetic relationship.

In many animal species, the microbiome has been shown to contribute to adaptability, such as digestion, metabolism, and immunity of the host. In general, the physiological conditions of hosts affect the host-associated microbiome and it also changes dynamically. Also, the host's genetic variations play the important role in the formation of the host-associated microbiome. However, it is not well understood whether such specificity is simply due to genetic or individual differences, phylogenetic restriction, or coevolution. In this project, we research the genotype and phylogenetic relationship of the host, Daphnia pulex, affected the host-associated microbiome. D. pulex, for which the phylogenetic relationship is known, were collected from healthy, starved, and dead conditions to examine the influence of host genotype and conditions on their microbiome. This experiment was conducted using eight genotypes of D. pulex. A1, A5, A6, and B genotypes belong to the JPN1 linage, and AR05, PL7, PL4, and HO01 genotypes belong to the JPN2 linage. In total, we collected 96 samples.