Longer time scale for human evolution

Longer time scale for human evolution.

D uring the past few years, the best estimates of the human single nucleotide mutation rate have been cut in half. Until recently, estimates of mutation rate have relied on counting substitutions between primate species and assuming that fossil relatives of living species can accurately pin dates onto phylogenetic branches. This procedure allows very precise estimates, but introduces systematic...

Establishing a time-scale for plant evolution.

• Plants have utterly transformed the planet, but testing hypotheses of causality requires a reliable time-scale for plant evolution. While clock methods have been extensively developed, less attention has been paid to the correct interpretation and appropriate implementation of fossil data. • We constructed 17 calibrations, consisting of minimum constraints and soft maximum constraints, for di...

Immunological time scale for hominid evolution.

Several workers have observed that there is an extremely close immunological resemblance between the serum albumins of apes and man. Our studies with the quantitative micro-complement fixation method confirm this observation. To explain the closeness of the resemblance, previous workers suggested that there has been a slowing down of albumin evolution since the time of divergence of apes and ma...

P-86: Longer Culture of Human Blastocysts Doesn

Longer time steps for molecular dynamics

Simulations of the dynamics of biomolecules have been greatly accelerated by the use of multiple time-stepping methods, such as the Verlet-I/r-RESPA ~reversible reference system propagator algorithms! method, which is based on approximating ‘‘slow’’ forces as widely separated impulses. Indeed, numerical experiments have shown that time steps of 4 fs are possible for these slow forces but unfort...