FASTQC Base mass distribution map

The horizontal axis represents each base position, reflecting the reading length information, such as the reading length of the sequencing is 150bp, the horizontal axis is 1 to 150;

The ordinate represents the base mass value,

The box plots in the figure represent the distribution of mass values of all bases at each location,

The middle red line represents the median number.

The upper and lower ends of the area filled with yellow represent the upper four and the lower four.

The top line of the box chart represents 90%, the bottom of the short term represents 10%

The Blue line represents the average

Background color from top to bottom is green, orange, red; Representing very good, reasonable, poor respectively; divide base mass into 3 different standards

A warning is given when there is a position of 10% four or less than 10, or if the median is less than 25;

When there is a position of 10% four the number of bits less than 5 or the median is less than 20 will be prompted to fail;

As shown in the following:

From the above picture we can see that the reading length of 75bp, the first 15bp about the quality of the sequencing is very good;

With the sequencing, due to the consumption of reagents and other reasons, the quality of sequencing began to gradually reduce, the final 60-75bp quality is very poor;

FASTQC Base mass distribution map