Month: September 2022

NEW CONCEPT. "In this way what historically seemed to be competing and selfish viruses can instead provide a unifying collective of viruses (and their defective participants) to better explain evolution, conservation as well as the plasticity and often cumulative genetic identities of complex organisms more coherently than the previous quasispecies concept." https://lnkd.in/eWydwab View in LinkedIn

FRAGMENT FROM NATURE continues with the theme of endosymbiont inheritance as part of a spectrum that concluded in the permanent engulfment of algae to form the permanent organelles chloroplasts and mitochondria during our evolutionary past. It also continues on the theme that biological individuality is an old concept and that we are holobionts, mosaic creatures composed of the genes of many species. View in LinkedIn

SONG OF DARWIN. "The more I study nature, the more I become impressed […] that the contrivances and beautiful adaptations [acquired through natural selection] transcend in an incomparable degree [those] which the most fertile imagination of the most imaginative man could suggest with unlimited time at his disposal." https://lnkd.in/eykUy37 View in LinkedIn

SHAPING EVOLUTION. "Obligate symbiotic relationships shape the evolution of partner lineages. In symbioses that are mutually beneficial, partners evolve traits that enable and stabilize the symbiosis: this cooperative coevolution is emphasized in most studies of symbioses. Genomic work has also revealed that obligate symbiosis produces unusual genome modifications, including extreme reduction, rapid protein evolution, and codon reassignments, all of which are evident in ancient obligate symbionts of insects." https://lnkd.in/dcBwzRs View in LinkedIn

HIDDEN HANDS IN THE WHEEL. "Recent studies suggest that host genomes also have acquired unusual modifications that are linked to symbiosis, including acquisition of genes from bacterial donors that seem to play a role in controlling or supporting symbionts." https://lnkd.in/dcBwzRs View in LinkedIn

LAWLESS RABBIT HOLE. "We refer to the commitment to obligate, inherited symbiosis as the evolutionary “rabbit hole” of obligate symbiosis, implying a generally irreversible journey into a very odd world where the usual rules do not apply. Broadly, the symbiosis rabbit hole refers to the confluence of selection and neutral evolution in generating the extreme patterns of genomic evolution observed in symbiotic partners." https://lnkd.in/dcBwzRs View in LinkedIn

ABSOLUTE ADDICTION. "The continuous presence of a vertically transmitted symbiont leads to the evolution of developmental dependence beyond the symbiont’s original contribution; that is, hosts become addicted to their symbionts. In aphids, elimination of Buchnera through antibiotic treatment interferes with development, which typically stalls if Buchnera fails to colonize." https://lnkd.in/dcBwzRs View in LinkedIn

WITHDRAWAL CRASH. "Aphid females deprived of Buchnera, due to heat, antibiotics, or old age, produce few or no progeny, even when dietary nutrition is sufficient. This dependence on Buchnera for development reflects 150 million years of fixation of aphid mutations that are beneficial or neutral in the presence of Buchnera but potentially deleterious in its absence." https://lnkd.in/dcBwzRs View in LinkedIn

SPECIAL PACKAGING. "Reflecting their reliance on symbionts, hosts have evolved specialized mechanisms and tissues for housing and supporting symbionts and for transferring them from mother to progeny. In aphids, cells that are specified to become bacteriocytes show distinctive gene expression in early developmental stages, and their cellular fate is determined before Buchnera colonization." https://lnkd.in/dcBwzRs View in LinkedIn

APHID ENDOSYMBIONT. "Bacteriocyte expression of genes underlying amino acid metabolism complements Buchnera pathways for amino acid biosynthesis, reflecting extensive host–symbiont collaboration in this central nutritional function. Certain aphid genes seem to function solely in controlling or supporting Buchnera." https://lnkd.in/dcBwzRs View in LinkedIn