Year: 2022

NEW HYMN BOOK. "The one-genome/one-organism doctrine of classical genetics has been eclipsed by studies of hereditary symbiosis. Microbial symbionts form a second type of genetic inheritance."​ https://lnkd.in/ddVyNR5 View in LinkedIn

VERTICAL SYMBIONTS. "Arthropods often acquire their symbionts vertically though the maternal germline as well as horizontally from the environment. Mammals obtain them through the maternal reproductive tract and from the mutual licking and grooming following birth."​ https://lnkd.in/ddVyNR5 View in LinkedIn

COSELECTION. "The microbial symbionts represent diverse genomes; and those genomes can also be coselected together with the genome of their host. In aphids, symbiotic bacteria provide selectable allelic variation (thermotolerance, color, parasitoid resistance) that enable some hosts to persist better under different environmental conditions."​ https://lnkd.in/ddVyNR5 View in LinkedIn

HORIZONTAL TRANSFER. "There is also allelic variation in the human microbiome. The genes of Bacteroides plebeius differ in different human populations. The Japanese strain contains at least two genes (horizontally transferred from a marine relative) that enable the bacteria to metabolize complex sugars, such as those found in seaweeds."​ https://lnkd.in/ddVyNR5 View in LinkedIn

MATE SELECTION. "Recent studies in Drosophila, for instance, demonstrate that the symbionts (not alleles of nuclear genes) provide important pheromonal cues necessary for mating preference."​ https://lnkd.in/ddVyNR5 View in LinkedIn

GROUP SELECTION. "Symbionts can therefore provide selectable allelic variation such that the entire group—the holobiont—is the selectable entity rather than either host or symbiont alone. Thus, microbes provide a second hereditary system that enables holobiont survival and selection."​ https://lnkd.in/ddVyNR5 View in LinkedIn

NOT. "We are not individuals by genetic criteria."​ https://lnkd.in/ddVyNR5 View in LinkedIn

SO ENDS this contemplation on the theme of biological individuality. From the rugged individualism and clear speciation of Darwin, we find the biological world view suggesting that creatures are spectral mosaics of interdependent and co-evolving species and that the whole ecosystem may be inherited through generations. A profound sea-change in thinking. View in LinkedIn

EARLY OXIDATIVE STRESS. "The sudden appearance of O2 would have led to significant oxidative stress due to incompatibilities with core cellular biochemical processes. These early oxygenic organisms likely adapted to the oxidative stress by co-opting preexisting systems (exaptation) with fortuitous antioxidant properties."​ https://lnkd.in/d9Uw3mh View in LinkedIn

ANCIENT PROTEINS. "The energy-converting enzymes evolved from ancestral enzymes that functioned in conditions of low O2 concentration or anaerobicity. These ancestral proteins did not have to deal with the inevitable side-reactions (leaks) that occur when O2 is present."​ https://lnkd.in/dxpcWx8 View in LinkedIn