Data from: Fitness change in relation to mutation number in spontaneous mutation accumulation lines of Chlamydomonas reinhardtii

Although all genetic variation ultimately stems from mutations, their
properties are difficult to study directly. Here, we used multiple
mutation accumulation (MA) lines derived from five genetic backgrounds of
the green algae Chlamydomonas reinhardtii that have been previously
subjected to whole genome sequencing to investigate the relationship
between the number of spontaneous mutations and change in fitness from a
non-evolved ancestor. MA lines were on average less fit than their
ancestors and we detected a significantly negative correlation between the
change in fitness and the total number of accumulated mutations in the
genome. Likewise, the number of mutations located within coding regions
significantly and negatively impacted MA line fitness. We used the fitness
data to parameterize a maximum likelihood model to estimate discrete
categories of mutational effects, and found that models containing one to
two mutational effect categories (one neutral and one deleterious
category) fitted the data best. However, the best-fitting mutational
effects models were highly dependent on the genetic background of the
ancestral strain.