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NEW PARADIGM. "Asserting the core importance of persistent virus to host survival thus presents a big break from historic views in evolutionary biology and adds a process of selection that stems from the horizontal transmission of persistent virus. As the virosphere provides no ‘virus-free' habitat for any life form, all living forms have adapted to their own viral habitat." https://lnkd.in/etdQ9rN View in LinkedIn

CODONS. “The nucleotide triplet that codes an amino acid is called a codon. A codon consists of three nucleotides. Three nucleotides per codon are needed to code 20 amino acids; since there are 64 combinations of 4 nucleotides taken three at a time and only 20 amino acids, the code is degenerate (more than one codon per amino acid, in most cases).” https://lnkd.in/dTpzG-s View in LinkedIn

PURIFYING SELECTION. "In recent years, substantial empirical evidence has arisen, suggesting that these effects may be pervasive in humans and other organisms." https://lnkd.in/dy3iVS5 View in LinkedIn

DIVERSITY REDUCTION. "Purifying selection at many linked sites alters patterns of molecular evolution, reducing overall diversity and distorting the shapes of genealogies." https://lnkd.in/dy3iVS5 View in LinkedIn

"PURIFYING selection acts to remove deleterious mutations, and variation linked to these mutations, as they continually arise in a population. This leads to reduced genetic diversity at both selected sites and linked neutral sites. This effect, known as background selection, can significantly affect the patterns of diversity evident in sequence data." https://lnkd.in/dy3iVS5 View in LinkedIn

SO ENDS this two weekend glimpse into the impact of viruses on evolution. The impact of viruses on human evolution specifically, is the subject of a book by Lluis Villareal cited herein, written for the interested non-virologist, and a fascinating read. Future research will undoubtedly reveal more about these curious creatures that have so closely co-evolved with life. https://lnkd.in/dsD6pVn View in LinkedIn

MITOCHONDRIAL LINK. “The fact, that the virus EsV-1 channel is associated with the mitochondria, suggests that this channel protein acquired domains that sort the protein to this organelle. The competition for the right molecular sorting machinery must have affected the evolution of this protein. Since the EsV-1 protein is in the mitochondria, this channel might be part of an early anti-apoptotic system important for viral persistence.” https://lnkd.in/dsexZC2 View in LinkedIn

FOUNTAIN OF SPARE PARTS. “Since viruses typically have high mutation and recombination rates as well as very high reproduction rates relative to their hosts, a relaxed selection due to complementation, for instance, may be an evolutionary mechanism that enhances the creation of new genes in viral genomes. This is consistent with the occurrence of many small genes of unknown function in viral genomes (ORFans) including numerous small membrane proteins.” https://lnkd.in/dsexZC2 View in LinkedIn

NEW LINEAGE. “The latter hypothesis of a viral origin for K+ channels is not that surprising, when one considers that many other viruses code for very simple and viral specific proteins with ion channel functions. In these examples, some or all K+ channels in cellular organisms might be derived from ancestral viral proteins.” https://lnkd.in/dsexZC2 View in LinkedIn

ANCIENT VIRAL ORIGINS. “Another scenario is that viral channel homologs evolved prior to or at the time of the divergence of eukaryotic algae. The viral K+ channels could arise from an ancient cellular organism, which served as a host for these viruses before they developed their present host specificity, or they might directly originate from the ancient virus world.” https://lnkd.in/dsexZC2 View in LinkedIn