Aussie marsupials descended from common South American ancestor

July 29th, 2010 - 1:49 pm ICT by ANI  

Melbourne, July 29 (ANI): The kangaroo and all other Aussie marsupials, such as wombats and Tassie devils, have a common South American ancestor, suggests new research.

According to previous research, the marsupial family tree began in what is now Australia some 120 million years ago with some migrating to South America while it, Australia and Antarctica were one giant land mass.

Thereafter, South American marsupials began their own evolutionary journey when the continents split nearly 80 million years ago. However, scientists found few fossils to support the theories.

Researchers at Germany’s Munster University turned to an unusual genetic marker to unravel the mystery.

They analysed the genomes of the South American opossum and the Australian tammar wallaby, as well as the DNA of 20 other marsupials for a “jumping gene” called retroposons.

Even as the rest of an animal’s genetic code can mutate, retroposons and their locations are stable, making them a reliable indicator of relationships between animals.

The scientists found all marsupials shared the same 10 retroposons, meaning they all descended form a common ancestor, reports The Courier Mail.

However, since South American marsupials had fewer retroposon updates, they are the older branches of the marsupial tree.

The scientists concluded that the single ancestor of Australian marsupials migrated from South America - and not the other way around - before the landmass split.

Their findings of the study appear in the journal PLoS Biology. (ANI)

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