FIG. 1.

Conservation of genomes sizes in Buchnera. Buchnera chromosomes digested with rare-cutting restriction enzymes were run on pulsed field gels to estimate genome sizes. Lanes are labeled by the abbreviation for the host name (Ap, A. pisum; Rp, R. padi; Sg, S. graminum; Mr, M. rhois). Note that I-CeuI cuts once and linearizes the Buchnera chromosome. With this enzyme, genomes sizes of Buchnera from S. graminum, R. padi, and A. pisum are indistinguishable. The finding of a slightly smaller genome size of Buchnera from M. rhois is supported by several independent enzyme digests.