In Science this week, members of the Ruminant Genome Project (RGP) publish three studies presenting the initiative's first findings. In one paper, researchers generate and analyze de novo assembled genomes of 44 ruminant species, representing all six Ruminantia families. They use the genomes to create a time-calibrated phylogenic tree of the animals, resolving the evolutionary history of many ruminant genera. Among their other findings are genes and regulatory elements that may have been involved in the evolution of the digestive system, cranial appendages, immune system, metabolism, body size, cursorial locomotion, and dentition of these ruminants. In the second paper, RGP investigators report the genetic basis of ruminants' bony headgear, which vary in form and function among different families. They compare 221 transcriptomes from headgear-bearing ruminant families and the genomes of two lineages that convergently lack headgear against the genomic background provided by the RGP, finding similar gene expression profiles and a common cellular basis between bovid horns and cervid antlers. Notably, they also discover that the regenerative properties of antler tissue are due to the exploitation of oncogeneic pathways and the high expression of some tumor suppressing genes. In the final paper, RGP researchers delve into the genetics behind reindeers' ability to survive in the Arctic. They compare the genomes of reindeer against other ruminants and non-ruminant mammals, and find genes involved in light arrhythmicity, high vitamin D metabolic efficiency, the antler growth trait of females, and docility that are either mutated or under positive selection in reindeer.
Also in Science, Harvard Medical School's Wendy Garrett discusses current research into the role of the microbiome in colorectal cancer (CRC) and calls for the incorporation of microbiome data into the prevention, diagnosis, and treatment process for the disease. "A valuable resource needed for the advancement of CRC-microbiota studies is an atlas to map not only what microorganisms are present in the tumor microenvironment but also where they are within and on tumors, how they interact with one another and the host, and how their arrivals and departures over time shape the evolving tumor," she writes. Also important are studies using prospective, longitudinal cohorts of healthy populations — which can complement research in patient populations to help understand both the factors that increase CRC susceptibility and those that decrease risk — and the application of model systems to advance microbiota discovery toward CRC diagnostics and therapeutics.