Analysis of the base substitutions found in the Xenopus laevis 5 S RNA pseudogene

A 5 S RNA pseudogene is associated with the major oocyte 5 S RNA gene of Xenopus laevis. X. borealis has several oocyte specific 5 S RNA genes. Gene 1 is the dominant 5 S RNA gene. Gene 3 has sometimes been referred to as a pseudogene. We show that the base substitutions in the X. laevis 5 S pseudogene are non-random with respect to double and single-stranded regions of the 5 S RNA using the chi 2 test of homogeneity with Yates correction for continuity. In addition, conserved positions of eukaryotic 5 S RNAs are predominantly maintained. X. borealis gene 3 is random in mutations.