Studies on Metatherian Sex Chromosomes. IX. Sex Chromosomes of the Greater Glider (Marsupialia : Petauridae)

Abstract

The greater glider, currently but incorrectly known as Schoinobates vo/ans, is widely distributed in forested regions in eastern Australia. All animals studied from six different localities had 20 autosomes but there were four chromosomally distinct populations. At Royal National Park, N.S.W., all female greater gliders studied had 22 chromosomes including two large submetacentric X chromosomes with subterminal secondary constrictions in their longer arms. This form of X chromosome occurred also at Bondo State Forest, Myall Lakes and Coff's Harbour, N.S.W., and at Eidsvold, Qld. At Coomooboolaroo, Qld, the X chromosome was also a large submetacentric but a secondary constriction occurred in the shorter arm. Two chromosomally distinct types apparently occur in Royal National Park, one with XY m,ales as in all other populations, and one with XY1Y2 males. Y or Yb but not Y 2, chromosomes were eliminated from the bone marrow in all populations but were present in spermatogonia, primary sperrnatocytes and cultured fibroblasts. Animals from Bondo State Forest had three or more acrocentric or metacentric supernumerary chromosomes.

Petauroides volans (Diprotodontia: Pseudocheiridae)

“…However, variations in the morphology of the X and Y chromosomes have been found to occur, such that 2-6 supernumerary (or B) chromosomes may be present Martin 1965, 1969;McQuade et al 1994;Murray et al 1979).…”

Sex-chromosome elimination in the bandicoot <i>Isoodon macrourus</i> using Y-linked markers

“…The Y chromosome is eliminated from bone marrow tissues and retained in cultured fibroblasts and the germ line in these possums, as it is in bandicoots. Both supernumerary and sex chromosomes are eliminated in the bandicoot Echymipera kalabu (Hayman et al, 1969); however, the supernumerary chromosomes found in P. volans are not lost from somatic tissues (Murray et al, 1979). Y chromosome elimination is also found in two South American marsupials.…”

“…P. volans has an XY 1 Y 2 sex-chromosome constitution in some populations and is XY in other populations. This species eliminates either the Y or the Y 1 but not the X chromosome (Murray et al, 1979). The Y chromosome is eliminated from bone marrow tissues and retained in cultured fibroblasts and the germ line in these possums, as it is in bandicoots.…”

“…X chromosome elimination occurs in some species of eutherians (Fredga, 1970), but Y chromosome elimination from somatic tissues has been reported only for marsupials (Murray et al, 1979), except as a phenomenon of aging in humans (Guttenbach et al, 1995). It occurs in two species of the Australian pseudocheirid possum, Hemibelideus lemuroides and Petauroides volans, neither of which are closely related to bandicoots.…”