Figure 1.
RNA-FISH activity maps of the platypus Xs and chicken Z chromosomes.
Bars represent the percentage of homogametic nuclei transcribing 2 (blue), 1 (red) or 0 (grey) alleles for each locus. Loci in pseudoautosomal regions (grey boxes) were tested in both male (indicated by a circle) and female (indicated by a star). Green coloring on platypus Xs represents homology to the chicken Z [23]. Platypus X chromosomes are not to scale (see Figure S5). Genes denoted by * were analysed in [24].
Figure 2.
Transcriptional activity of neighbouring chicken Z loci and platypus X5 loci in fibroblasts.
Gene names are color coded to correspond to signal color. A) In nuclei with only one allele active for both genes the signals co-locate in both sexes. B) Nuclei from the homogametic sex in which both genes are 2Z/2X-active. C) Nuclei from the homogametic sex in which the active Z/X expresses both genes and the other (inactivatable) Z/X expresses only one gene.
Table 1.
RNA-FISH analysis of transcription from neighbouring loci in homogametic nuclei.
Table 2.
Frequency of nuclei transcribing both alleles of neighbouring loci.