Aboriginal Australians have been genetically isolated from the rest of humanity for 50,000 years with no direct evidence that they had ever intermarried with South-East Asians about 4,000 years ago, as some scholars have suggested, a DNA study has revealed.
A detailed analysis of the male Y chromosome from 13 Aboriginal men found no traces of DNA from other ethnic groups, such as people from the Indian sub-continent who were thought to have migrated to Australia about 2000BC.
http://www.sott.net/article/313075-Abor ... 0000-years
Take particular note of the number. 300 miles of open water. 50,000 years ago. Seems the Darwinian Caveman's finally on the ropes