Figure 3

Distances between all tissues studied. To illustrate the degree of variation in HERV-W gag expression patterns between tissue types and individuals, distances (mean squared differences of mixing proportions) were calculated. The average frequency distributions in all non-CNS and CNS tissues were used as references, which were calculated by adding all corresponding tissue data together. Distances from the references to individual tissues were defined as the sums of squares of mixing proportion differences, Tm-category by Tm-category. Panel A shows the variation in HERV-W gag expression pattern between averages of tissues. The red lines indicate distances between each CNS tissue to the average frequency distribution of all CNS tissues. The blue lines indicate distances between each non-CNS tissue to the average of all non-CNS tissues. The green line connecting the two nodes represents the distance between average CNS and non-CNS tissue frequency distributions. Panel B shows variations in HERV-W gag expression pattern between individuals and tissues for the subset of the data where individual tissue samples were available. The green, red and blue lines are the same as in Panel A. The distance to each individual is calculated relative to the average frequency distribution of each tissue. Panel C shows the variation in HERV-W gag expression pattern between human primary fibroblast cultures and the variation after serum deprivation. The two nodes represent the average pattern of expression in the five individual cultures under control and serum deprived culture conditions.