In my case it seems to pull the first name from sAMAccountName.  The last name is the domain, there is no display name and the email address is the SAMAccountName with the @domain.com concatenated.  I would think that SN would be used for last name; givenName for the first name; displayName for the display name and mail for the eMail.  For smart card use it would also be useful to have distinguishedName in the DB as well.

I compared my profile with an LDAP read to get the information above.  I've checked in AD Users and Groups and in the DNN Users table to confirm what I stated.  For example here is information from AD:

In my profile ClarkW is listed as my last name.