using System;

using AutoMapper;

public class Program

{

    public class Source

    {   

        public int A { get; set; }

        public string Str { get; set; }

    }

​

    public class DestinationBase

    {

        public int A { get; set; }

    }

    public class DestinationDerived : DestinationBase       

    {

        public string Str { get; set; }

    }

    public static void Main()

    {

        Mapper.Initialize(cfg => {

            cfg.CreateMap<Source, DestinationBase>();

            cfg.CreateMap<Source, DestinationDerived>()

                .IncludeBase<Source, DestinationBase>();

        });

        var src = new Source() { A = 1, Str = "foo" };

        var dest = new DestinationBase();

        Mapper.Map(src, dest);

        Console.WriteLine("dest.A: " + dest.A);

    }

}