One of my new AncestryDNA autosomal matches has the last name of Rucker–she has no tree. It’s also the maiden name of my 4th great-grandmother. The last name is not unusual and most of us are related distantly through an early 18th century immigrant to Virginia. Most, but not all. That’s the first thing to remember.
I do not want to assume that my new DNA match connects to me through her strict paternal line because I also have that name in my family tree. There are several things to consider. Rucker could be her married name, or the name of a step-parent who adopted her, both of which would change things immediately. Even if Rucker is her birth name, she could be related to me on another family entirely. The amount of DNA we share is small (10 cM). We also have no shared matches to allow me to narrow down where we likely connect.
Even if her earliest male Rucker ancestor is the same as my Rucker ancestor, it is still possible that the DNA we share comes from another common ancestor in another portion of her tree entirely. Given that we have no shared matches and there’s not tree, any conclusions are speculative.