Number of standard deviations away from the background for selected reduced taxonomic classes, with a negative value representing classes with lower representation in the specified population than the background, and a positive value representing a higher representation in the specified population than the background. Classes are ordered from least to most thermally evolved moving from left to right, with the most substantial under-representation in the C complex, and the most substantial over-representation in the V class and S/Q/V/A complex.