Table 2.
Dependent Variable | Independent Variablesa | Adjusted R2 b | Test Statistic(F)c | df | P |
Shotgun human-chimp divergence values | |||||
3 Mb | .083 | 8.07 | 1, 475 | .005 | |
100 kb | .072 | 24.71 | 1, 475 | 9×10-7 | |
Local | .060 | 26.76 | 1, 475 | 3×10-7 | |
BAC human-chimp divergence values | |||||
3 Mb | .159 | 4.59 | 1, 98 | .035 | |
100 kb | .181 | 8.57 | 1, 98 | .004 | |
Local | .130 | 7.58 | 1, 98 | .007 | |
SeattleSNP human-chimp divergence values | |||||
3 Mb | .071 | 1.63 | 1, 71 | .205 | |
100 kb | .072 | 4.86 | 1, 71 | .031 | |
Local | .078 | 6.37 | 1, 71 | .014 | |
Human-baboon divergence values | |||||
3 Mb | .203 | 3.38 | 1, 110 | .069 | |
100 kb | .136 | 7.72 | 1, 110 | .006 | |
Local | .395 | 18.35 | 1, 110 | 4×10-5 |
“3 Mb,” “100 kb,” and “local” refer to the CpG, GC, and polyAT content at each scale (see “Materials and Methods” section).
The adjusted R2 is the proportionate reduction of the variance in transformed divergence values achieved by the introduction of recombination rates and sequence motifs in a given regression model. Note that R2 values are not comparable across data sets. In particular, they depend on the variance of the error terms, which will differ across data sets, because of varying precision of divergence estimates (see “Materials and Methods” section). They also depend on the range of the independent variables.
By use of a partial F test, we examine whether adding the recombination rate to the regression model explains a larger proportion of the variance in divergence values than do the three aspects of sequence content alone.