Kangaroo gene mapping and sequencing: insights into mammalian genome evolution

Abstract

Abstract. The deep divergence of marsupials and eutherian mammals 160 million years ago provides genetic variation to explore the evolution of DNA sequence, gene arrangement and regulation of gene expression in mammals. Following the pioneering work of Professor Desmond W. Cooper, emerging techniques in cytogenetics and molecular biology have been adapted to characterise the genomes of kangaroos and other marsupials. In particular, genetic and genomic work over four decades has shown that marsupial sex chromosomes differ significantly from the eutherian XY chromosome pair in their size, gene content and activity. These differences can be exploited to deduce how mammalian sex chromosomes, sex determination and epigenetic silencing evolved.

Desmoglein-2 during pregnancy and its role in the evolution of viviparity in a marsupial (Sminthopsis crassicaudata; Dasyuridae)

“…The number of desmosomes in the uterine epithelium of S. crassicaudata decreases over the course of pregnancy. Marsupials diverged from placental mammals 160 million years ago (Luo et al, 2011) allowing time for differing mechanisms to evolve (Freyer et al, 2003;Graves, 2013) for cell adhesion and the process of live birth (viviparity). Despite marsupials having a short-lived placenta with low contribution to offspring development compared with the placenta of most eutherians (Selwood and Johnson, 2006;Renfree et al, 2013), S. crassicaudata shows a similar redistribution and decrease in the number of desmosomes throughout pregnancy to those of eutherian mammals (Illingworth et al, 2000;Preston et al, 2004) and squamates (Biazik et al, 2010).…”

Desmond Wishart Cooper: a life in science

“…Professor Jenny Graves gives a fascinating personal insight into Des' early career in her review of kangaroo gene mapping and sequencing (Graves 2013). A review of marsupial X chromosome inactivation provides further insights into mammalian genome evolution (Deakin 2013).…”