Year: 2022

"YOUNG SPECIES are highly prone to extinction via increased gene flow after human-caused environmental changes. This mechanism of biodiversity loss, often termed reverse speciation or introgressive extinction, is of exceptional interest because the parent species are typically highly differentiated ecologically." https://lnkd.in/d8VqUA2 View in LinkedIn

DRIVER OF ECOLOGICAL CHANGE. "Reverse speciation events are potentially powerful case studies for the role of evolution in driving ecological changes, as the phenotypic shifts associated with introgressive extinction can be large and they occur over particularly short timescales." http://www.sciencedirect.com/science/article/pii/S0960982216000403 View in LinkedIn

REVERSAL TO NOVELTY. "Reverse speciation can lead to novel phenotypes, which may in turn produce novel ecological effects." The natural cycle. http://www.sciencedirect.com/science/article/pii/S0960982216000403 View in LinkedIn

ECOSYSTEM IMPACT. "The community and ecosystem impacts of reverse speciation were novel, and yet they were also predictable based on ecological and morphological considerations. The rapid nature and resultant ecological impacts associated with reverse speciation demonstrates the interplay between biodiversity, evolutionary change, and ecosystem function." http://www.sciencedirect.com/science/article/pii/S0960982216000403 View in LinkedIn

SO ENDS this contemplation of the reversal of speciation. I am reminded of the relatively recent awakening that the mercator projection of the relative sizes of continents gives a false sense of importance to some continents, because of the elongation of latitudes on flat maps. The illusion of a visual representation became a truth in 1569 and only recently came to light (but is still the basis of Google maps today). So with the illusion of the timelines of man, the epochs of the natural world, selective in its simplified viewpoint, unable to capture the numerous exceptions, perpetuating a cartoon view of evolution. And particularly, the linear tree of life. http://www.businessinsider.com/mercator-projection-v-gall-peters-projection-2013-12 View in LinkedIn

NEW UNIFYING THEORY. "Taking a number of theoretical considerations into account, we propose here a unifying model for organelle inheritance. We argue that uniparental inheritance arises to avoid the spread of selfish (faster replicating) organelle genomes that are maladaptive and/or incompatible with the host nucleus." https://lnkd.in/d34vWHz View in LinkedIn

NEW THEORY. "However, uniparental inheritance is evolutionarily unstable, because organelles are subject to Muller's ratchet. This drives a relaxation of strict maternal inheritance by paternal leakage or regular biparental transmission. Biparental inheritance is again susceptible to the evolution of selfish genomes and, therefore, is repeatedly lost and restored over evolutionary timeframes." https://lnkd.in/d34vWHz View in LinkedIn

ESCAPING THE RATCHET. "The mutational meltdown by Muller's ratchet is escaped from by episodes (or longer periods) of sexual recombination between organelle genomes. Importantly, sexual oDNA recombination is not sufficient to stop the spread of selfish cytoplasmic elements." https://lnkd.in/d34vWHz View in LinkedIn

SELF-DAMAGE. "The observed maternal predominance in uniparental transmission is due to a higher mutational load of paternal cytotypes, which in turn is caused by oxidative damage and/or genetic drift and is most pronounced if oDNA copy numbers in the sperm cell are small. The load is high enough to favor the evolution of paternal gamete-controlled organelle exclusion mechanisms (“killing one's own cytoplasm”)." (oDNA = organelle DNA). https://lnkd.in/d34vWHz View in LinkedIn

UNSOLVED. "Polyploidy and free vegetative segregation of organelles and their genomes are hallmarks of cytoplasmic inheritance. Why the DNA-containing organelles, chloroplasts, and mitochondria, are inherited maternally is a long standing and unsolved question." Non-Mendelian inheritance. https://lnkd.in/d34vWHz View in LinkedIn