Figure 2
From: Both selective and neutral processes drive GC content evolution in the human genome
Analysis of fixed versus polymorphic retrotransposon insertions. (A) Analysis of average GC content flanking polymorphic (P, white) and fixed (F, gray) retrotransposons. GC content was calculated in 5 kb flanking the repeat. The number of repeat instances is also indicated. GC content is significantly higher for regions flanking fixed compared to polymorphic Alus ; the same holds for SVAs. (B) Analysis of polymorphic (white) and fixed (gray) retrotransposon relative frequency in different isochores (L1 to H3, ordered from 1 to 5, as described in [20]). Fixed Alus are significantly enriched in heavy isochores compared to polymorphic instances.