>1. What was his evolutionary ancestor like?
2. How do you know?
3. How many features does the Ubx deficient mutant share with its presumed
ancestor besides having two sets of wings?<<
1. and 2. I am a little uncertain what you are asking in #1. The
Pennsylvanian mayfly nymphs have wings on each segment. Knocking out certain
genes produce this feature. (see Nature Feb. 3, 1994 p. 460ff) The presumed
evolutionary ancestors had already been laid out prior to the time of this
work. Thus these experiments act as confirmations of evolutionary
predictions.
Do we have a genealogy of the fly's history? No. But in historical
theorizing, which is what evolution is, if I can say thus and such happened,
then go out and find that evidence, it acts like a confirmation. A recent
example in more recent work is the brouhaha about whether the Indo-Europeans
brought farming with them as they displaced other aboriginal peoples, or
whether the aboriginal peoples adopted the languange and technology of the
very successful farmers. Each view makes predictions which can be searched
for. If I recall correctly, the former view just got some confirmation from
mitochondiral DNA work.
3.It is not likely to share every feature because the mutations in genomic
phase space are mathematically, a random walk. Thus many features are altered
and can not be recovered. As to how many, an exact number? I don't know.
Art wrote:
>1. Did a reptile leg turn into a bird leg?
2. Did the biologists learn anything about how a reptile leg turned into a
bird leg?
3. Can a reptile leg turn into a bird leg in a few days?<
1. No. But this is the equivalent to a physicist's or astronomer's
experiment of making the clock run backwards. By doing this you can see
where things came from. I recently read that some calculations of the orbits
of the local galactic group, when run backward show that there have probably
been some interesting collisions in the recent galactic past. The question
of the origin of the moon (i.e. capture or formation in situ) involve runing
the clock backwards. I do not see why biologists should be denied this type
of tool.
2. I. think so. You might not and I might be wrong. But doesn't it strike
you as odd that this procedure yields a reptile leg from a bird leg? I see no
way to explain this except by evolution, unless someone can show that this
type of manipulation yields random morphologies. This why I asked about any
examples which form "non-ancestor" features e.g., mammalian legs/arms/skulls.
3. Possibly, with the correct mutation, but I don't think this has been
observed. And it would be accomplished during embryo development. I
certainly can't take the adult lizard outside my door and produce chicken
legs.
glenn