Gene Loss or Expansion--Tree--question

[Tobias McNultey]

.        __________________Anoph1
--------[
        [                             ____________Anoph2
        [                          [
        [__________________________[
                                   [____________Dros2





      ___________________________________ Mouse1
     [
     [
---[
     [                          ________ Dros1
     [_________________________[
                               [     _____ Anoph1
                               [____[
                                    [___Anoph2

I am wrting a paper comparing  some  genes in
Anopheles and Drosophila. There are cases where
Anopheles has an extra gene (in a family) compared to Drosophila--
I figure it is either gene expansion in Anoph or gene  *loss*
in Drosophila. I'm going to say that when I get the bottom tree
it must be gene duplication/divergence in Anoph but when I get
the top tree it's gene loss in Drosophila. How would I say it though?
  Top tree "must be gene loss in Drosophila because gene duplication
/divergence of gene 1 and 2 occurred before divergence of
Anoph and Drosophila"? Is that the proper interpretation?
Please let me know. NJ and ML tree show same tree (top).
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