Qualitative Analysis of Inquiries Received by FDA Regarding Conduct of Clinical Trials during the Covid-19 Public Health Emergency.

Background: This report describes the U.S. Food and Drug Administration (FDA) experience in establishing a dedicated mailbox, and in publishing related guidance, to address concerns among interested parties regarding the conduct of clinical trials during the COVID-19 public health emergency (PHE).

Exceptional LINE density at V1R loci: the Lyon repeat hypothesis revisited on autosomes.

The mammalian olfactory system utilizes three large receptor families: the olfactory receptors (ORs) of the main nose and the vomeronasal type-1 and type-2 receptor genes (V1Rs and V2Rs) of the vomeronasal organ. We find that these loci are among the most long interspersed nuclear element (LINE)-dense regions of mammalian genomes. We investigate two evolutionary models to account for this cohabitation.

Co-regulation of a large and rapidly evolving repertoire of odorant receptor genes.

The olfactory system meets niche- and species-specific demands by an accelerated evolution of its odorant receptor repertoires. In this review, we describe evolutionary processes that have shaped olfactory and vomeronasal receptor gene families in vertebrate genomes. We emphasize three important periods in the evolution of the olfactory system evident by comparative genomics: the adaptation to land in amphibian ancestors, the decline of olfaction in primates, and the delineation of putative pheromone receptors concurrent with rodent speciation.

Divergent V1R repertoires in five species: Amplification in rodents, decimation in primates, and a surprisingly small repertoire in dogs.

The V1R gene family comprises one of two types of putative pheromone receptors expressed in the mammalian vomeronasal organ (VNO). We searched the most recent mouse, rat, dog, chimpanzee, and human genome sequence assemblies to compile a near-complete repertoire of V1R genes for each species. Dog, human, and chimpanzee have very few intact V1Rs (8, 2, and 0, respectively) compared to more than a hundred intact V1Rs in each of the rat (106) and mouse (165) genomes.