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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

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

SO ENDS this contemplation of inheritance of symbionts, the loss of the biological individual, and the idea that we are genetic mosaics of many species, and the seemingly outlandish idea that the permanent cellular powerhouses (the mitochondria and chloroplast), could have come about by engulfment of a foreign species, is made more credible by the universal symbiosis between species, genetic streamlining and metabolic outsourcing. 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

ANCIENT MATERNAL INHERITANCE. "The presence of maternal transmission at the base of the Animalia kingdom and the surprising plasticity by which microbes gain access to germ cells or embryos in these systems signifies that maternal symbiont transmission is an ancient and evolutionarily advantageous mechanism inherent in animals, including humans." https://lnkd.in/ds5gpCY View in LinkedIn