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GREAT UNKNOWN. "More than 25,000 bacterial and archaeal host genomes are available in NCBI RefSeq (January 2015), whereas only 1,531 of their viruses were entirely sequenced and most (86%) of these derive from only 3 of 61 known host phyla. Thus, although advances in high-throughput sequencing expand the bounds of viral sequence space, these data sets are dominated by uncharacterized sequences (usually 60–95%), termed ‘viral dark matter’." https://elifesciences.org/content/4/e08490 View in LinkedIn

NUMERICAL ADVANTAGE. “Selfing can evolve in response to an extremely diverse array of selective agents, but its intrinsic 3 : 2 transmission advantage is ever present (up to 50%). This specific advantage arises because a selfing individual, in a stable population, transmits a total of three copies of alleles: two through self-fertilized seeds, and a single copy as an outcrossed pollen parent.” http://onlinelibrary.wiley.com/doi/10.1111/nph.12182/full View in LinkedIn

SO ENDS this dalliance into the world of biological dark matter. Next weekend we will dip into what we do know about these tiny unknown creatures, and see how important they have been in our evolution and in planetary affairs. But to say that we are still in the Biological Dark Ages is an understatement. We know so little about the real biodiversity of our planet, both big and small. View in LinkedIn

ARTHROPOD VIRAL RESERVOIR. "We similarly documented a remarkable diversity of genome structures in arthropod viruses, including a putative circular form, that sheds new light on the evolution of genome organization. Hence, arthropods are a major reservoir of viral genetic diversity and have likely been central to viral evolution." https://lnkd.in/dhUCtkZ View in LinkedIn

VIRAL POOL. "The huge diversity of negative-sense RNA viruses in insects, spiders and other arthropods suggests that these animals could be central to virus origin and evolution." https://lnkd.in/dYBnxsT View in LinkedIn

OBSCURE RNA VIRUSES. "Most of these analyses have focused on viruses with genomes that are made of DNA or positive-sense RNA, and there have been fewer studies of viruses with genomes made of negative-sense RNA. Therefore, the evolutionary history of negative-sense RNA viruses, which are responsible for influenza, measles, Ebola and many other diseases in animals and plants, remains obscure." https://lnkd.in/dYBnxsT View in LinkedIn

OVER 100 NEW VIRUSES FOUND. "Zhang and co-workers found that the 112 new viruses were spread across the major lineages of the negative-sense RNA viruses. These discoveries fill some major gaps in our knowledge, and allow the tree of viral relationships to be updated. For example, this latest work confirms that the viruses of the Arenaviridae genus—which generally infect rodents—belong to the Bunyaviridae family along with two previously unclassified genera of viruses that infect plants." A drop in the bucket. https://lnkd.in/dYBnxsT View in LinkedIn

MODULAR VIRAL DIVERSITY. "When considering viral diversity at the genus level, the network displays a modular topology. These results confirmed the prediction that ‘at macroevolutionary scales, host–phage interaction matrices should be typified by a modular structure’, as also had been observed across 215 phage types against 286 host types of unknown diversity." https://elifesciences.org/content/4/e08490 View in LinkedIn

BLACK HOLE. "While recent advances in high-throughput sequencing and viral metagenomics continue to expand the bounds of viral sequence space, such viruses are typically unlinked to cognate hosts, severely limiting ecological and evolutionary inferences." https://lnkd.in/dYBnxsT View in LinkedIn

CHALLENGES. "Studying the genetics of the viruses in these communities is challenging. There is no single ‘marker’ gene that can be used to identify all viruses in environmental samples. Also, many of the fragments of viral genomes that have been identified have not yet been linked to their host microbes. Many viruses integrate their genome into the DNA of their host cell, and there are computational tools available that exploit this ability to identify viruses and link them to their host. However, other viruses can live and multiply inside cells without integrating their genome into the host's DNA." https://elifesciences.org/content/4/e08490 View in LinkedIn