background nucleus(t)ide analogs (nas), containing lamivudine (lmv), adefovir dipivoxil (adv), endeavor (etv), telbivudine (ldt), and tenofovir (tdf) are widely used for the treatment of chronic hepatitis b (chb), but long term anti-hepatitis b virus (hbv) therapy with nas may give rise to the emergence of drug-resistant viral mutants. objectives this study aimed to find and identify some new r...

The molecular clock of neutral mutations, which represents linear mutation fixation over generations, is theoretically explained by genetic drift in fitness-steady evolution or hitchhiking in adaptive evolution. The present study is the first experimental demonstration for the molecular clock of neutral mutations in a fitness-increasing evolutionary process. The dynamics of genome mutation fixa...

A statistics-based adaptive non-uniform mutation (SANUM) is presented for genetic algorithms (GAs), within which the probability that each gene will subject to mutation is learnt adaptively over time and over the loci. SANUM uses the statistics of the allele distribution in each locus to adaptively adjust the mutation probability of that locus. The experiment results demonstrate that SANUM perf...

Adaptive mutation is a process by which an organism under nonlethal selective pressure produces mutations that relieve the selective pressure (see reference 5 for a review). It is illustrated particularly well by Escherichia coli strain FC40, a strain bearing an F episome carrying a lac allele with a frameshift mutation that makes it phenotypically Lac . When FC40 is plated on lactose-minimal m...

Stationary-phase mutation in microbes can produce selected ('adaptive') mutants preferentially. In one system, this occurs via a distinct, recombination-dependent mechanism. Two points of controversy have surrounded these adaptive reversions of an Escherichia coli lac mutation. First, are the mutations directed preferentially to the selected gene in a Lamarckian manner? Second, is the adaptive ...

Hill-Robertson interference (HRi) is expected to reduce the efficiency of natural selection when two or more linked selected sites do not segregate freely, but no attempt has been done so far to quantify the overall impact of HRi on the rate of adaptive evolution for any given genome. In this work, we estimate how much HRi impedes the rate of adaptive evolution in the coding genome of Drosophil...

In 1988 John Cairns, Julie Overbaugh, and Stephan Miller published a paper entitled “The origin of mutants,” in which they suggested that bacteria could choose which mutations to make (11). Shortly thereafter, Cairns and I began collaborating on a National Science Foundation-funded project to investigate the genetic basis of what was popularly called “directed mutation” (although at the time we...