Nope. Active Directory Domain Services and DNS are two different server roles. They work tightly together but does not mean they are on the same machine. I had a Domain Controller which wasn't a DNS server at one site as well as the other way around, a server had DNS but not AD.
Microsoft Active Directory Domain Services are the foundation for
distributed networks built on Windows 2000 Server, Windows Server 2003
and Microsoft Windows Server 2008 operating systems that use domain
controllers. Active Directory Domain Services provide secure,
structured, hierarchical data storage for objects in a network such as
users, computers, printers, and services. Active Directory Domain
Services provide support for locating and working with these objects.
And even better:
What is the AD DS server role?
AD DS provides a distributed database that stores and manages
information about network resources and application-specific data from
directory-enabled applications. Administrators can use AD DS to
organize elements of a network, such as users, computers, and other
devices, into a hierarchical containment structure. The hierarchical
containment structure includes the Active Directory forest, domains in
the forest, and organizational units (OUs) in each domain. A server
that is running AD DS is called a domain controller.
From: Active Directory Domain Services Overview