Evolutionary Breakpoints ONE

Figure 1

Two-colour FISH of lemur-specific DNA probes for STS and SRY to metaphase chromosomes of (a) the ring-tailed lemur (L.catta) and (b) the crowned lemur (E.coronatus). The colors of the inserted gene names correspond to those of the fluorescence signals (green, biotin-FITC; red, digoxigenin-TRITC) on the DAPI- counterstained plates. Note that STS maps at the distal long arm segments of X and Y, and SRY maps in a distinct and clearly visible distance proximal to STS on the Y chromosomes of both lemur species, X and Y centromeres are marked by small bars.

Figure 2

Schematic comparison of the FISH mapping data of genes on R-banded idiogrammatic layouts of the X and Y chromosomes of human, ring-tailed lemur and crowned lemur. Brackets that connect the genes within the yellow colored meiotic X-Y pairing segment (PAR) indicate that a discrimination of these loci was not possible by FISH, thus the relative order is unknown in lemurs. Note that PRK and STS are X- and Y-specific in the human, but map within the PAR in lemurs, and that SRY maps close to the PAR in human but distant from the PAR in lemurs.

Literature: Glaser B, Myrtek D, Rumpler Y, Schiebel K, Hauwy M, Rappold GA, Schempp W. (1999) Transposition of SRY into the ancestral pseudoautosomal region creates a new pseudoautosomal boundary in a progenitor of simian primates Hum Mol Genet 8:2071-8 ( > Publication in full text )