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FRAGMENT FROM NATURE. It is generally thought that evolution is the march towards greater structural and genetic complexity. Not quite so simple. Genetic outsourcing during genetic streamlining is deceptive. It actually increases genetic complexity, and amplifies gene capabilities by appropriation of host genes during the symbiotic or parasitic lifestyle, not just being genetic simplification or genome reduction. Remember the reversal of polyploidy during plant evolution? View in LinkedIn

"MALE SELF-SACRIFICE”, or apparent male cooperation with female cannibalism, is part of male copulatory behavior in several spider species, and in some insects. One study also reported that males of the spider Argiope aurantia spontaneously die when they copulate." http://www.esciencecentral.org/journals/are-internal-death-promoting-mechanisms-ever-adaptive-2329-9002.1000113.pdf View in LinkedIn

KIN FITNESS. "Pea aphids (Acyrthosiphon pisum) that are parasitized by the Braconid wasp Aphidius ervi drop from the host plant, causing their own death. These insects live in groups of close kin, and their death prevents their body from producing parasites that would then attack their siblings. Death therefore increases the individual’s inclusive fitness, or equivalently, increases the fitness of the kin group." http://www.esciencecentral.org/journals/are-internal-death-promoting-mechanisms-ever-adaptive-2329-9002.1000113.pdf View in LinkedIn

PLANTS. "Plant cells, that have, in addition to mitochondria, another endosymbiotic organelle of cyanobacterial origin, the chloroplast. Do chloroplasts play a role in the regulation of plant programmed cell death? And since an AP-ATPase, a metacaspase and a TIR domain have been identified in cyanobacteria (as in some other bacterial lineages), did plants acquire their putative homologues of the apoptotic machinery through this endosymbiotic process?" http://www.nature.com/cdd/journal/v9/n4/full/4400950a.html View in LinkedIn

CLUSTERING VS ENCODING. "The mitochondria appear to be a locus of clustering of several of the main players in the execution and regulation of programmed cell death. Interestingly, all these players, whether located inside the mitochondria or on its outer surface, are encoded by nuclear genes, and none by mitochondrial genes." (Streamlining of endosymbiont ensured this when the engulfed bacteria transferred most of its genes to the host nucleus). http://www.nature.com/cdd/journal/v9/n4/full/4400950a.html View in LinkedIn

PART B. "A complementary picture emerges with respect to time. A steady influx of mutations affects the whole reproductive span. Hazards begin to increase linearly with time at all ages. At older ages, where selective pressure is always low, this linear increase continues unabated, whereas at younger ages it is slowed for a while by outflow due to natural selection." http://www.pnas.org/content/110/25/10141.full View in LinkedIn

PARASITIC SIMPLIFICATION. "It has been well known for decades that the evolution of numerous parasitic and symbiotic organisms entails simplification rather than complexification. In particular, bacteria that evolve from free-living forms to obligate intracellular parasites can lose up to 95% of their gene repertoires without compromising the ancestral set of highly conserved genes involved in core cellular functions." http://onlinelibrary.wiley.com/doi/10.1002/bies.201300037/full View in LinkedIn

THE THEORY UNRAVELS. "However, if we try to construct an equilibrium with some specific wall of death, we find too little remaining net fertility very close to the wall to balance mutation there. Each wall of death implies an earlier one. The instability propagates down through the whole reproductive span, and our construction unravels." http://www.pnas.org/content/110/25/10141.full View in LinkedIn

THEORY CONTINUED. "At sufficiently advanced ages, remaining net fertility necessarily drops below any mutation rate that is bounded below. If the force of selection depends only on remaining net fertility, selection cannot balance mutation, and such ages must lie beyond a wall of death." http://www.pnas.org/content/110/25/10141.full View in LinkedIn

THE THEORY. "Lotka’s intrinsic rate of natural increase, with respect to an increment to age-specific mortality at an age a. Thus, he obtained a linear approximation for loss in fitness due to any deleterious mutations that raised mortality at an age a. The greater the loss in fitness, the faster should mutant alleles be selected out of a population, and the fewer should be found at equilibrium as recurring mutations balance natural selection." https://lnkd.in/eyTNv3H View in LinkedIn