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IMMUNE INNOVATION. "CRISPR-Cas9 deletion of a subset of these ERV elements in the human genome impaired expression of adjacent IFN-induced genes and revealed their involvement in the regulation of essential immune functions, including activation of the AIM2 inflammasome. Although these regulatory sequences likely arose in ancient viruses, they now constitute a dynamic reservoir of IFN-inducible enhancers fueling genetic innovation in mammalian immune defenses."(ERVs = endogenous retroviruses; IFN = interferon). https://lnkd.in/dn8M8m8 View in LinkedIn

JUMPING GENES AND IMMUNITY. "We found that ERVs have shaped the evolution of a transcriptional network underlying the interferon (IFN) response, a major branch of innate immunity, and that lineage-specific ERVs have dispersed numerous IFN-inducible enhancers independently in diverse mammalian genomes." (ERVs = endogenous retroviruses). https://lnkd.in/dn8M8m8 View in LinkedIn

ABUNDANT MOBILE ELEMENTS. "Endogenous retroviruses (ERVs) are abundant in mammalian genomes and contain sequences modulating transcription. The impact of ERV propagation on the evolution of gene regulation remains poorly understood." https://lnkd.in/dn8M8m8 View in LinkedIn

NET LOSS. "The loss of macromolecular constituents during plant tissue senescence is not associated with a concomitant rise in metabolite levels but rather with a decline in total carbon and nitrogen within the tissue. Indeed, the implied transport of metabolites out of the leaf has been substantiated in a number of cases." https://lnkd.in/dNWP3KD View in LinkedIn

GENETIC NOVELTY. "Transposable elements (TEs) are the key players in generating genomic novelty by a combination of the chromosome rearrangements they cause and the genes that come under their regulatory sway. Genome size, gene content, gene order, centromere function, and numerous other aspects of nuclear biology are driven by TE activity." https://lnkd.in/daec-Ac View in LinkedIn

SPARED UNTIL LAST. "Autolytic changes in the cell do not extend injtially to the mitochondria or nucleus, both of which remain unaffected until very late in the process of senescence." https://lnkd.in/dNWP3KD View in LinkedIn

SECOND PROPOSITION. "Second, viruses and mobile elements contribute specific genes that play major roles in the emergence of coherent wholes at a new level of complexity." https://lnkd.in/dwWBEqU View in LinkedIn

NEW HISTORY. "(i) Cyanobacteria originated before the GOE, (ii) multicellularity coincides with the beginning of the rise of oxygen, and (iii) three clades representing the majority of extant cyanobacteria evolved shortly after the accumulation of atmospheric oxygen." (GOE = Great Oxygenation Event). http://www.pnas.org/content/110/5/1791.full View in LinkedIn

MULTICELLULARITY ROLE. "Our results indicate an origin of cyanobacteria before the rise of atmospheric oxygen. The evolution of multicellular forms coincides with the onset of the GOE and an increase in diversification rates. These results suggest that multicellularity could have played a key role in triggering cyanobacterial evolution around the GOE." (GOE = Great Oxygenation Event). http://www.pnas.org/content/110/5/1791.full View in LinkedIn

SO ENDS a peek into the complexity of the control of leaf fall timing. This is influenced by numerous factors, both internal and external. It remains stunning, to me at least, that despite this complexity, trees march inexorably by species, one by one, exactly in synch, into the autumn leaf coloration and subsequent leaf drop. May your autumns be filled with wonder. View in LinkedIn