(A) Chromosomal localizations of PpD6 (D6), PpD6+ (D6+), Pp1- Y1 (Y1), and Pp1-Y2 (Y2) genes. Chromosome segments are symbolized by horizontal bars, the coloring identifies Muller elements C, B and chromosome Y in blue, pink, and black, respectively. The directions of the coding regions are indicated by arrows, pointing from 5′ to 3′ in the sense strand. In chromosome Y the positions and orientations of inactive viral reverse transcriptase (RT), pol and gag genes are also shown for orientation; here the arrows represent only the relative directions within a short DNA segment. (B) The G−C content in the coding regions of the PpD6, PpD6+, Pp1- Y, and Pp1-Y2 genes. The upper part of the panel shows the average G−C content + SD for all PPP genes of a given species, while the lower part depicts the G−C content of the four selected phosphatases.