Sex-chromosome elimination in the bandicoot Isoodon macrourus using Y-linked markers

Cytogenetic studies have shown that the Y chromosome is eliminated from many somatic cell types of the bandicoot Isoodon macrourus, an Australian marsupial. Molecular techniques allow examination of a greater range of tissue types than that possible using cytogenetic techniques. The presence or absence of the Y chromosome was established using partial sequences of the Y-linked SRY and UBE1Y genes in I. macrourus, with the X-linked gene G6PD as a control. We show that a very small proportion of cells comprising hematopoietic tissues, and even fewer cells in peripheral blood, retain the Y chromosome. The Y chromosome is retained in most brain, liver, kidney, and lung cells and in cardiac and skeletal muscle. We also show that the bandicoot Y chromosome is retained in some cell types within tissues previously believed to completely eliminate the Y chromosome.