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Article: New genome research data have been reported by scientists at Australian National University.
- Article from:
- Science Letter
- Article date:
- August 26, 2008
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"In therian mammals (placentals and marsupials), sex is determined by an XX female: XY male system, in which a gene (SRY) on the Y affects male determination. There is no equivalent in other amniotes, although some taxa (notably birds and snakes) have differentiated sex chromosomes," scientists in Canberra, Australia report (see also Genome Research).
"Birds have a ZW female: ZZ male system with no homology with mammal sex chromosomes, in which dosage of a Z-borne gene (possibly DMRT1) affects male determination. As the most basal mammal group, the egg-laying monotremes are ideal for determining how the therian XY system evolved. The platypus has an extraordinary ...