What ancestry companies provide actual genetic data?

This question is inspired by an article in today's New York Times business section ("DNA Tests Find Branches but Few Roots"). The article is nice in that it compares the cost of ancestry testing by various companies, shows that results differ, and quotes Henry Louis Gates Jr. making reasoned assessments of the role that DNA testing can play. However, the article fails to say which companies provide customers with the raw genotype information that they can use to make their own assessments as more information becomes publicly available.


This map (from the article) shows the results returned to the author (Ron Nixon) from five different companies. Presumably, the actual genetic information they gathered is a bit less variable than their interpretation. If I paid to have my DNA analyzed, I would want the actual data so that I could make my own interpretations using the best information available from all sources.

The article lists 20 companies that will test your DNA for the purpose of learning about ancestry. Can anyone tell us which ones provide the client with the actual information (sequence or polymorphism data) that can be compared with published genetic demographic data?

What can I learn about my ancestors from my DNA?

What can I learn about my ancestors from my DNA? What companies provide this information? How much does it cost? What exactly do I learn?