Bio-Rad Image Lab™ Software - Manual (Page 79)

Setting Up a Default Protocol
User Guide | 79
Standard Lanes
Choose the lane that contains your standards by typing lane numbers or the words
First and Last in the Standard Lanes field. The format is xx, xx, xx, ... where xx is the
lane number. For example, if you run an 18-well gel and you want your standards in
lanes 1, 10, and 18, enter First, 10, and Last.
Note: Lane detection works best when standards are placed in the first and
last lanes.
Regression Methods
A regression method is used to calculate the molecular weight of the unknown
bands. The software uses the relative front and molecular weight values of the
standard bands to calculate the standard curve. The standard curve is then used to
calculate the values of the unknown bands. The shape of the standard curve is
based on the selected regression method. Choose one of four regression methods.
The methods and the minimum number of standard bands required for each type
are shown in the following table.
Table 6. Regression methods and minimum number of bands
Linear (semilog) 2
Point-to-point (semilog) 2
Logistic 5
Cubic spline 5
If you do not have enough data points for the selected method, the molecular
weight of the unknown bands is not calculated.
Select the appropriate method for the gel type:
 Gradient gels: The linear (semilog) regression method works well for these
gels because the mobility of the bands is linear to the log of their molecular
Regression Method Minimum Number of
Standard Bands