Figure 3 : Mutations and genome duplications.

From: The genome sequences of Arachis duranensis and Arachis ipaensis, the diploid ancestors of cultivated peanut

Figure 3

Frequency distributions are shown of values of synonymous substitutions (KS) for paralogous and orthologous genes in comparisons of A. duranensis (Ad), A. ipaensis (Ai) and Glycine max (Gm). Peaks in the G. maxG. max comparison represent the Glycine whole-genome duplication (WGD) at KS = 0.10 (10 million years ago) and the early papilionoid WGD at KS = 0.65 (58 million years ago). The same early papilionoid WGD also affected the Arachis lineage, so the shift in the A. duranensisA. duranensis and A. ipaensisA. ipaensis peaks (at KS = 0.90 and 0.95, respectively) indicates that Arachis has accumulated silent changes at a rate 1.4 times faster than that in G. max. On the basis of average rates of change for Arachis of 8.12 × 10−9 KS/year, we estimate that A. duranensis and A. ipaensis diverged 2.16 million years ago.