Month: September 2022

ANCIENT INFECTIONS. "Viruses were already infecting organisms some 300 million years ago, suggests a new study on what may be the oldest date yet for the emergence of an insect-infecting virus." They are considered to have emerged before modern cells. https://lnkd.in/d-szGeg View in LinkedIn

ANCIENT VIRAL RESURRECTION."A 35 Mio-year-old HERV was reconstructed from several defective HERV sequences by deduction of a consensus sequence as infectious virus, designated Phoenix." https://lnkd.in/eGaw2Kq View in LinkedIn

VIRAL FOSSIL RECORD IS DNA. "The genomes of many organism contain endogenous viral elements (EVEs). These DNA sequences are the remnants of ancient virus genes and genomes that ancestrally 'invaded' the host germline. For example, the genomes of most vertebrate species contain hundreds to thousands of sequences derived from ancient retroviruses." https://lnkd.in/dPyAFVt View in LinkedIn

EXOTIC VIRUS PROPERTIES. "Viruses can have exotic properties: they can replicate in dead cells, repair radiation-damaged hosts, or recombine with other dead viruses and generate an intact cell. In some cases, hosts can benefit from viruses. An ancient retrovirus supported the development of the placenta in mammals." https://lnkd.in/eGaw2Kq View in LinkedIn

VIRAL DNA INSERTED INTO HOST. "The replication cycle of a retrovirus entails the insertion ("integration") of a DNA copy of the viral genome into the nuclear genome of the host cell. Most retroviruses infect somatic cells, but occasional infection of germline cells (cells that produce eggs and sperm) can also occur. The retroviral proteins themselves have (sometimes) been co-opted to serve novel host functions, particularly in reproduction and development. " https://lnkd.in/dwG2wT9 View in LinkedIn

VIRAL DNA IN HUMAN GENOME. "Human endogenous retrovirus (HERV) proviruses comprise a significant part of the human genome, with approximately 98,000 ERV elements and fragments making up nearly 8%." Some infected human genomes at least 150,000 years ago. https://lnkd.in/dwG2wT9 View in LinkedIn

VIRUSES BUILD GENOMES of other species, at a significant rate. "Their contribution to mammalian genomes is probably underestimated because TEs have diverged beyond recognition. Most of them are inactivated by mutations so that they cannot replicate. They make up one third of our genome." (TE = transposable elements). https://lnkd.in/eGaw2Kq View in LinkedIn

VIRUSES ARE GENETIC INNOVATORS. "The huge population of viruses, combined with their rapid rates of replication and mutation, makes them the world’s leading source of genetic innovation: they constantly “invent” new genes." https://lnkd.in/dQ2abpA View in LinkedIn

NUCLEUS IS OF VIRAL ORIGIN? "I contend that the cell nucleus itself is of viral origin. The nucleus may have evolved from a persisting large DNA virus that made a permanent home within prokaryotes." This has support In sequences of DNA polymerase genes but remains debated. http://www.scientificamerican.com/article.cfm?id=are-viruses-alive-2004&page=3 View in LinkedIn

"VIRAL PARTICLES are much more abundant than cells and viral genes outnumber cellular ones in the biosphere. Cellular genomes also harbour many integrated viruses whereas cellular genes are rare in viral genomes. The gene flux from virus to cell is thus overwhelming if compared with the opposite event. Cells are giant pickpockets of viral genes and can mimic viral biology." http://www.sciencedirect.com/science/article/pii/S1879625713001077 View in LinkedIn