Figure 2

Histogram of the copy number by date of insertion for 10 LTR retrotransposon families. The LTR divergence is an estimate of the insertion date of the copies, each time scale corresponding to a LTR divergence of 0.01 (0.385 My). For complete copies, ("2 LTRs") this divergence corresponds to the divergence between the two LTRs. For truncated copies (Internal Region [IR], LTR, and LTR-Internal region [LTR-IR]), the divergence is derived from the "2 LTRs" copies (see Materials and Methods and Figure 1).