Category: Uncategorized

OPPOSING FORCES. "We have argued that symbionts are prone to evolve in directions detrimental to hosts, due both to genetic drift in clonal symbiont populations and to selection favoring selfish traits. An implication is that hosts are continually selected to compensate." https://lnkd.in/dcBwzRs View in LinkedIn

OBLIGATE SYMBIONTS. "Many show far more extreme genome reduction than does Buchnera. Indeed, symbiont genomes have repeatedly evolved to be the very smallest genomes known in cellular organisms (aside from organelles), with total gene counts often

OUTSOURCING COLLABORATION. "With more genome sequencing, it became apparent that Buchnera genomes in different aphid lineages continue to undergo irreversible gene loss, over long and short time scales. Similar ongoing gene loss is evident in every obligate symbiont clade for which multiple genomes have been sequenced." https://lnkd.in/dcBwzRs View in LinkedIn

GENETIC STREAMLINING. "Symbiont genome decay affects genes in all functional categories. The first obligate symbiont genome sequenced, that of Buchnera of the pea aphid, was most notable for the fact that it had undergone extensive gene loss and contained no novel genes yet did retain genes for biosynthesis of essential amino acids needed by hosts." https://lnkd.in/dcBwzRs View in LinkedIn

DRASTIC MEASURES. "A well-documented force affecting heritable symbionts is genetic drift leading to the fixation of neutral or deleterious mutations that cause gene inactivation, gene loss, or inefficiency of gene products. The basis for elevated genetic drift is the drastic shift in population genetic structure that occurs when a free-living microorganism adopts an obligate symbiotic lifestyle." https://lnkd.in/dcBwzRs View in LinkedIn

REPRESSING IMMUNITY. "Accommodation of symbionts may require that hosts suppress or modify immune responses, potentially elevating risk of pathogen invasion. In aphids, many genes underlying responses to Gram-negative bacteria have been eliminated, including the immune deficiency signaling pathway (IMD), peptidoglycan receptor proteins, and antimicrobial peptides." https://lnkd.in/dcBwzRs View in LinkedIn

BLURRED BOUNDARY. "Taken together, these findings for the Buchnera–aphid symbiosis point to extensive genomic and metabolic integration of symbiotic partners and blur the distinction between symbiont and organelle." https://lnkd.in/dcBwzRs View in LinkedIn

VIRAL DIVERSITY. "With the sole exception of large dsDNA viruses, all major classes of viruses display greater diversity in eukaryotes than in prokaryotes." (dsDNA = double stranded DNA). https://lnkd.in/dHhQ6QH 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

DEEP LINK. "The tight coupling between the earliest stages of viral and cellular evolution." https://lnkd.in/dHhQ6QH View in LinkedIn