`--abskew` *real*
: Set the minimum abundance skew ratio between a chimera and its
  potential parent. The assumption is that chimeras appear later in
  the PCR amplification process and are therefore less abundant than
  their parents. Any positive value equal or greater than 1.0 can be
  used. Default is 16.0, which means that the parents should be at
  least 16 times more abundant than the chimera.
