Matrotrophy, the continuous extra-vitelline supply of nutrients from the parent to the progeny during gestation, is one of the masterpieces of nature, contributing to offspring fitness and often correlated with evolutionary diversification. The most elaborate form of matrotrophy-placentotrophy-is well known for its broad occurrence among vertebrates, but the comparative distribution and structu...

The bacterial tree of life has recently undergone significant expansion, chiefly from candidate phyla retrieved through genome-resolved metagenomics. Bypassing the need for genome availability, we present a snapshot of bacterial phylogenetic diversity based on the recovery of high-quality SSU rRNA gene sequences extracted from nearly 7000 metagenomes and all available reference genomes. We illu...

Representatives of only four well-characterized bacterial phyla were isolated from a pasture soil by using liquid serial dilution culture. In contrast, members of Acidobacteria, Verrucomicrobia, and Gemmatimonadetes and of other poorly represented bacterial lineages were isolated in earlier experiments with solidified versions of the same media. We conclude that, contrary to expectation, liquid...

The time of origin of the animal phyla is controversial. Abundant fossils from the major animal phyla are found in the Cambrian, starting 544 million years ago. Many paleontologists hold that these phyla originated in the late Neoproterozoic, during the 160 million years preceding the Cambrian fossil explosion. We have analyzed 18 protein-coding gene loci and estimated that protostomes (arthrop...

At least five animal phyla exhibit spiralian development, which is characterized by striking similarities in the geometry of the early cleavage pattern and the fate map of the blastula, along with similarities in larval morphology. Recent advances in reconstructing the phylogeny of spiralians and their relatives suggest that the common ancestor of a large clade of protostome phyla known as the ...

The phylogenetic relationships of symbiotic bacteria from the xylophagous cockroach Cryptocercus (Cryptocercidae, Blattaria) were compared to those described in previous reports in lower termites. The 16S rDNA bacterial genes were PCR-amplified from DNA isolated from the entire hindgut using Bacteria-selective primers, and the 16S rDNA amplicons were cloned into Escherichia coli. The changes in...