Year: 2022

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

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

DRIVEN TO EXTINCTION. "At a snapshot in time, hazards lie low for a stretch of ages, climb at ages where remaining net fertility is dropping off, and link up with the old-age segment. As time goes by, the climbing phase shifts down to younger and younger ages, until the hazard rate at every adult age comes to be marching toward infinity. Unbounded accumulation of mutations across the whole reproductive span drives any population to extinction." http://www.pnas.org/content/110/25/10141.full View in LinkedIn

UNWOUND THEORY. "It seems logical that organisms should acquire mechanisms that push the age of onset of ill effects from numerous minor defects associated with genetic load toward later ages. However, our analysis suggests that such mechanisms, if carried to extremes, have bad evolutionary repercussions." http://www.pnas.org/content/110/25/10141.full View in LinkedIn

VAST RANGE. "Although mutations provide the ultimate material upon which natural selection depends, most mutations are deleterious, and in certain settings can lead to a substantial fitness load. We are attempting to understand the nearly 1000-fold range of variation in the mutation rate that exists across the Tree of Life, through the study of a diversity of invertebrates and unicellular eukaryotes and prokaryotes." http://www.bio.indiana.edu/faculty/directory/profile.php?person=milynch View in LinkedIn

ERROR RATES. "We have recently developed a novel method that allows us to estimate transcription error rates and the degree to which these vary among eukaryotic lineages. Remarkably, error rates at this level are typically >1000x those at the level of genome replication. The implication is that >1% of transcripts typically contain an erroneous base." http://www.bio.indiana.edu/faculty/directory/profile.php?person=milynch View in LinkedIn

MISSING REFERENCE. https://lnkd.in/dnzRdnG View in LinkedIn

GENETIC DRIFT. "We are promoting the idea that the power of random genetic drift imposes a lower bound to the degree to which natural selection can reduce the mutation rate. This drift-barrier hypothesis seems to support a number of previously disconnected observations, including the increase in the mutation rate with reductions in effective population size, the magnified error rates associated with DNA polymerases and repair enzymes used only infrequently in replication, and the extraordinarily high rates of base misincorporation into transcripts." https://biodesign.asu.edu/mechanisms-evolution/research View in LinkedIn

TWO GENE BUFFER. "It has long been appreciated that there is a limit to the number of deleterious mutations that an organism can sustain per generation. The presence of these mutations is usually not harmful, because diploid organisms generally require only one functional copy of any given gene." http://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1004351 View in LinkedIn

BAD GENE ACCUMULATION. "However, if the rate at which these mutations are generated is higher than the rate at which natural selection can weed them out, then the collective genomes of the organisms in the species will suffer a meltdown as the total number of deleterious alleles increases with each generation." http://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1004351 View in LinkedIn