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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

MAJOR EVOLUTIONARY ROLE. "Importantly, exonic splice enhancers appear to play a major role in shaping patterns of vertebrate sequence evolution. These motifs are under purifying selection, as evidenced both by their decreased rate of evolution at synonymous and nonsynonymous sites." https://lnkd.in/drMDPh6 View in LinkedIn

NEW PARADIGM. "With the discovery of a significant fraction of sites under strong constraint in Drosophila, two things become clear: the role of synonymous sites in the biology of genomes is far greater than the neutral, “silent” part they were once assumed to play; and we still have much to learn about the functionality encoded in genes." https://lnkd.in/dU2Q65U View in LinkedIn

EXONIC SPLICE ENHANCERS. "Here we test a further potential case of avoidance selection. We hypothesized that there could be avoidance of exonic splice enhancers in genes that do not contain introns. Exonic splice enhancers are short nucleotide motifs that are exceedingly common in vertebrate exons, especially near the splice sites." https://lnkd.in/drMDPh6 View in LinkedIn

NOT NEUTRAL. "Recent studies have uncovered a myriad of different types of functional information encoded into the coding sequence of genes beyond the protein recipe, including controls for translational efficiency and accuracy, splicing enhancers, micro-RNA binding, nucleosome positioning, and more." https://lnkd.in/dU2Q65U View in LinkedIn

AVOIDANCE SELECTION. "However, there is evidence that selection can also act to avoid a particular sequence motif if its presence in a given context is deleterious. This phenomenon, that we term “avoidance selection,” constitutes another facet of purifying selection and has been documented in a wide variety of biological systems." https://lnkd.in/drMDPh6 View in LinkedIn