Some 3.5 million of today's Ashkenazi Jews -- about 40 percent of the total Ashkenazi population -- are descended from just four women, a genetic study indicates.

Those women apparently lived somewhere in Europe within the last 2,000 years, but not necessarily in the same place or even the same century, said lead author Dr. Doron Behar of the Rambam Medical Center in Haifa, Israel.

He did the work with Karl Skorecki of the Technion-Israel Institute of Technology and others.

Each woman left a genetic signature that shows up in their descendants today, he and colleagues say in a report published online by the American Journal of Human Genetics. Together, their four signatures appear in about 40 percent of Ashkenazi Jews, while being virtually absent in non-Jews and found only rarely in Jews of non-Ashkenazi origin, the researchers said.

They said the total Ashkenazi population is estimated at around 8 million people. The estimated world Jewish population is about 13 million.

The theory of spontaneous evolution of life, in contrast to the religious worldview of creationism, has been given a boost with the  powerful telescopes on Hawaii confirming that a disk of dust and hot gases surrounding an infant star forming near our solar system is rich in two compounds needed for organic molecules and DNA.

The discovery offers a new hint at how life might have emerged on Earth. The compounds are common in our own solar system. The study of the star and the disk around it marks the first time that molecules of acetylene and hydrogen cyanide have been found in another system that seems to be developing in a similar manner as our own.

The forming star and the dust belt together are known as IRS 46, and make up a system that "might look a lot like ours did billions of years ago, before life arose on Earth," said Fred Lahuis of Leiden Observatory in the Netherlands, in a statement released by the W.M. Keck Observatory on Mauna Kea and the Jet Propulsion Laboratory of the California Institute of Technology. Lahuis is the lead author of a paper describing the results that will be published in an upcoming issue of the Astrophysical Journal Letters.