The minimal mammalian Y chromosome - The marsupial Y as a model system

Abstract

The mammalian X and Y chromosomes are very different in size and gene content. The Y chromosome is much smaller than the X and consists largely of highly repeated non-coding DNA, containing few active genes. The 65-Mb human Y is homologous to the X over two small pseudoautosomal regions which together contain 13 active genes. The heterochromatic distal half of the human Yq is entirely composed of highly repeated non-coding DNA, and even the euchromatic portion of the differential region is largely composed of non-coding repeated sequences, amongst which about 30 active genes are located. The basic marsupial Y chromosome (about 10 Mb) is much smaller than that of humans or other eutherian mam..