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EXAPTATION. “For instance, R. felis strain LSU-Lb, which carries Type V cif genes on its plasmid, infects a parthenogenetic insect. Accurate rooting of the cif gene tree together with functional characterization of these genes will be needed to confirm whether the ancestral function of these genes was to induce CI. However, the presence of a CI-inducing Wolbachia strain that has only Type V genes suggests that CI evolved very early in the evolution of cif genes.” (CI = cytoplasmic incompatibility). https://lnkd.in/dXjWp9f View in LinkedIn

REMAINING QUESTIONS. “This may explain why, to our knowledge, there are no reports of strains from these supergroups inducing CI. However, divergent Type V cif genes are found in other Rickettsiales, and here their phenotypic effects are uncertain. Gillespie et al. (2018) proposed that cif homologs found in Rickettsia may induce other reproductive phenotypes.” (CI = cytoplasmic incompatibility). https://lnkd.in/dXjWp9f View in LinkedIn

THE INCOMPATIBILITY GENES. “The cif genes are widespread across the Rickettsiales. Our large data set supported the observation of Lindsey et al. (2018) that cif genes are common in Wolbachia supergroups A and B. These supergroups contain most of the Wolbachia strains that have been described, and here the genes are tightly linked to the CI phenotype. The genes were absent from a small sample of Wolbachia strains from other supergroups.” (CI = cytoplasmic incompatibility). https://lnkd.in/dXjWp9f View in LinkedIn

UNTANGLING THE TRAIT. “The discovery of the genes underlying CI now makes it possible to reconstruct the trait’s evolution at the molecular level and infer the selection pressures acting on CI using the tools of molecular evolution.” (CI = cytoplasmic incompatibility). https://lnkd.in/dXjWp9f View in LinkedIn

WELL STUDIED. “CI is the most commonly observed reproductive manipulation induced by Wolbachia, and its evolution has been investigated for over 60 years through phenotypic experiments and evolutionary models.” (CI = cytoplasmic incompatibility). https://lnkd.in/dXjWp9f View in LinkedIn

ABORTION GENES IDENTIFIED. “Recent work on the Wolbachia strains wMel and wPip from Drosophila melanogaster and Culex pipiens has found that the bacterial genes cifA and cifB are sufficient to induce CI.” (CI = cytoplasmic incompatibility). https://lnkd.in/dXjWp9f View in LinkedIn

THE STRATEGY. “This leads to development failing unless the zygote inherits a Wolbachia from the mother that is able to rescue embryonic development (the rescue function). When the male and female parents are infected with different Wolbachia strains, it is also common to find that the cross is incompatible (bidirectional CI). This suggests the modification and rescue factors must match each other for development to proceed normally.” (CI = cytoplasmic incompatibility). https://lnkd.in/dXjWp9f View in LinkedIn

All matter forms patterns, many rather periodic. View in LinkedIn

EMERGENT PHENOMENA. “It has been observed that a large population of fireflies often display synchronized flashing. Each firefly tries to match its flashing with neighboring fireflies. As each firefly tries to synchronize with the others, the whole population of fireflies begins to flash together. This collective motion is only a result of interactions between members...and there is no leader who dictates the individual’s behavior. “ https://lnkd.in/dZaukdg View in LinkedIn

STARTING UPSTREAM. “Cytological studies have revealed that CI results from cytogenetic defects affecting the paternal chromosomes in early embryogenesis. As Wolbachia is not present in mature sperm, this suggests that Wolbachia modifies the sperm of infected males during spermatogenesis (the modification function).” (CI = cytoplasmic incompatibility). https://lnkd.in/dXjWp9f View in LinkedIn