Some aspects of the genetics of Australian marsupials, with an appendix on the genetics of monotremes.

Abstract

Except for their cytogenetics, marsupials have not been studied genetically until the last decade. This paper discusses various aspects of their genetics, excluding cytogenetics. (1) The choice of the best experimental animal is still uncertain. So far most work has been done on kangaroos of the genus Macropus, the brush-tailed possum Trichosurus vulpecula, and the potoroo, Potorus tridactylus. However, small dasyurids like Sminthopsis crassicaudata and Dasyuroides byrnei seem to have the most potential. (2) A brief summary is given of the genetic analysis of field data, particularly mother-pouch young combinations. (3) A comprehensive list of all the known biochemical polymorphisms is presented, together with some brief notes on their use to date in the analysis of speciation and population structure. ( 4) Sex chromosome behaviour in marsupials is discussed. Kangaroos appear to have paternal X-inactivation rather than the random X-inactivation characteristic of eutherians. The evidence for this hypothesis is summarized and possible exceptions to it noted. Mention is made of X and Y elimination in bandicoots. (5) The potential of marsupial cells for use in cell biology and somatic cell genetics is stressed, with a table giving characteristics of marsupial cell lines. (6) A summary of the little that is known of monotreme genetics is included in an appendix.