EXHIBIT A In accordance with Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended, each of the undersigned does hereby consent and agree to the joint filing on behalf of each of them of a statement on Schedule 13G and all amendments...

                                         EXHIBIT A

     In accordance with Rule 13d-1(k) under the Securities Exchange Act of 1934,
as amended,  each of the undersigned  does hereby consent and agree to the joint
filing  on  behalf  of  each  of them of a  statement  on  Schedule  13G and all
amendments thereto with respect to the Common Stock of Ardea  Biosciences,  Inc.
beneficially  owned by each of them,  and the  inclusion  of this  Joint  Filing
Agreement as an exhibit thereto.

Dated: February 14, 2007


                              /s/ Xxxx Xxxxxxxx
                              -----------------------------
                                  Xxxx Xxxxxxxx


                              XXXXXXXX EQUITY ADVISORS, L.L.C.
                              By:  Xxxx Xxxxxxxx

                              /s/ Xxxx Xxxxxxxx
                              -----------------------------
                              Name:  Xxxx Xxxxxxxx
                              Title: Managing Member

                              MAPLE LEAF CAPITAL I, L.L.C.
                              By: Xxxx Xxxxxxxx

                              /s/ Xxxx Xxxxxxxx
                              ------------------------------
                              Name:  Xxxx Xxxxxxxx
                              Title:  Managing Member


                              MAPLE LEAF PARTNERS, L.P.
                              By: Xxxx Xxxxxxxx


                              /s/ Xxxx Xxxxxxxx
                              ---------------------------------------
                              Name:  Xxxx Xxxxxxxx
                              Title:  Managing Member of its General Partner


                              MAPLE LEAF OFFSHORE, LTD.
                              By: Xxxx Xxxxxxxx

                               /s/ Xxxx Xxxxxxxx
                              ---------------------------------------
                              Name:  Xxxx Xxxxxxx
                              Title:  General Partner