Characterization of the human Xq21.3/Yp11 homology block and conservation of organization in primates

The Xq21.3/Yp11 homology block on the human sex chromosomes represents a re cent addition to the Y chromosome through a transposition event. It is beli eved that this transfer of material occurred after the divergence of the ho minid lineage from other great apes. In this paper we investigate the struc ture and evolution of the block through fluorescence in situ hybridisation, contig assembly, the polymerase chain reaction, exon trapping, sequence co mparison, and annotation of sequence data. The overall structure is well co nserved between the human X chromosome and the Y chromosome as well as betw een the X chromosomes from different primates. Although the sequence data r eveal a high level of nucleotide sequence identity for the human X and Y, t here are regions of significant divergence, such as that around the marker DXS214. These are presumably the consequence of multiple rearrangements dur ing evolution and are of particular importance with respect to the potentia l gene content in this segment of the interval. (C) 2001 Academic Press.