I am a Lewis! I took the 23andMe test. I'm not sure how that would work if I am a Woman! It is my Paternal last name for 4 generations that I know of. Let me know how it goes!

LEWIS DNA CHART ONLINE :  http://www.familytreedna.com/public/LEWISSurnameDNAProject/default....

See if anyone in your family is there!

My son (Taylor surname) did in-dept Mt-DNA and Y-DNA testing.  The Mt-DNA (full test) includes me and my direct mother's line.  My mother's mother was born a Lewis, but her mother  was not a Lewis ( born Randolph / Randall).  The only people I can match on the Lewis line are my grandmother's brothers (all deceased), and my grandmother's sisters and their female descendants.  Males inherit their mother's Mt-DNA, but it is NOT passed down to their children.  This is not very useful for Lewis genealogy, since I know of my closer relatives, but it might become more useful in the future as later female generations do not know their families.

The Taylor DNA test taught me a lot.  I had to increase markers several time to get relevant genealogical information.  I DID get relevant information useful for genealogy eventually.  Both Taylor and Lewis are common names.  I encourage people interested in doing DNA testing to start with in-depth tests.  These tests are more expensive, but worth it.  As far as I am concerned, the more simple, and less expensive DNA tests are worthless for people with common names, and a waste of money.

Yes, Michael is correct that the genealogy research is also important along with the DNA.  However the DNA results will tell you when there is an error in the genealogy research.  Errors are easy in researching common names. I have a lot of common names in my direct lines. The DNA results is grouped with others with similar results, if you do testing with a certain company.  This results can also be compared with results from other companies at a certain web site. 

The biggest problem with DNA testing seems to be people not testing in-depth.  Superficial tests do not show much.