Dependence of cell doubling time on generation number for old pole and new pole daughter cells.

a) Old pole daughter cells took longer to divide than new pole daughter cells (our linear mixed model analysis returned χ2df=1 =5.192, p = 0.023). For both cell types, division time progressively increased over successive generations (our linear mixed model analysis returned χ2df=1 = 38.327, p &lt; 0.001). This analysis was carried out including data for generations 2 to 11 from two experimental runs.<br>(b) Inspecting the 24-generation data set revealed that the progressive increase in division times gradually asymptotes to a steady state division time with increasing generation number (LMM: linear effect of generation number: χ2df=1 = 52.199, p &lt; 0.001; quadratic effect of generation number: χ2df=1 = 32.832, p &lt; 0.001). Old pole daughter cells also took longer to divide than new pole daughter cells within this 24-generation data set (LMM: χ2df=1 = 11.222, p = 0&lt;0.001). <br>