🚀 go-pugleaf

In article <ldsoderb.724677131@reading> David S. Oderberg,
ldsoderb@susssys1.reading.ac.uk writes:
>Could someone please tell me whether artificial breeding/selection has
>so far produced any new species, according to the generally accepted
>definition/s of `species' among biologists (interbreeding capacity etc.)?
>Even including the very latest in biotechnological achievements, has the
>creation of new species been attained?

The most obvious example is Zea mays (maize in Reading).  This species
was bred in Mexico before the conquistadores destroyed the lab notebooks
:-), so wee don't know exactly what process was used.  The domestic apple
is also a species that resulted from human intervention.  Most of the
food you eat comes from extreme variants of the wild species, usually
containg genes that have been introduced from related species.  Many may
be different enough that you would regard them as effectively being new
species.  This has been going on for millennia.

With plants, crossing barriers do not make a particularly effective
criterion for speciation because there are many ways to force crosses
that normally would not happen.  Beyond that, the question of what
consititutes a true species division is controversial enough that I am
not going to touch it.

The latest genetic engineering has not produced any new species, and to
my knowledge, that is not a goal of any of that work.  The benefit of
genetic engineering is that everything can be kept the same except for
one gene, thus changing the species as little as possible in other ways. 
Classic breeding brings in more extraneous genetic material, but genetic
engineering makes it possible to bring material in from a broader range
of organisms.

In article <ldsoderb.724677131@reading>,
ldsoderb@susssys1.reading.ac.uk (David S. Oderberg) writes:
|>
|>Could someone please tell me whether artificial breeding/selection has
|>so far produced any news species, according to the generally accepted
|>definition/s of `species' among biologists (interbreeding capacity etc.)?
|>Even including the very latest in biotechnological achievements, has the
|>creation of new species been attained?
|>
|>I am aware of the alleged creation of plant hybrids which can't be crossed
|>with either parent species: do these, if they exist, qualify?  

There are quite a lot of cases of this, if you use the generally accepted
definition of "same species" and "different species", namely, populations of
organisms that, if brought together geographically, will merge into a single
breeding population are considered to be in the same species, while those
that will remain distinct, due to physical or behavioral reproductive isolation,
are considered to be of different species.

Consider the domestic dog, for example.  Chihuahuas and Great Danes are quite
reproductively isolated, physically.  They are considerably more distinct on
both morphological and biological grounds than Mallard and Pintail ducks,
which are generally recognized as separate species, although they freely
interbreed and hybridize in captivity.  Yes, one can mix the two populations of
dogs  by "transitive closure" using intermediate breeds of dogs, but the
situation has several natural analogs to clinal variation among closely
related species in the wild, where the ends of the cline are reproductively
distinct and considered two species, but there is a chain of hybrids that
link the two populations.

Since new "species" of dogs can essentially be created this way more or less at
will by selective breeding, taxonomists don't bother to give them all status as
separate species, which technically they are entitled to, but instead lump them
all together in the single species Canis domesticus.  From a practical
standpoint, it simply isn't useful to consider all the domestic breeds and
strains as separate species.

--PSW

In article <ldsoderb.724677131@reading>, ldsoderb@susssys1.reading.ac.uk (David S. Oderberg) writes:
|> 
|> I am aware of the alleged creation of plant hybrids which can't be crossed
|> with either parent species: do these, if they exist, qualify?  

Yep, they qualify - allopolyploids (as they are called) are valid species.
In fact all of the standard 'breeds' of wheat are members of artificially bred
species.  The most common types of wheat grown today are hexaploids (twice
hybridized), but even most of the tetraploid wheats are artifically produced
(thought there *are* a few natural tetraploid wheats, I believe).

I forget the species names for the domestic wheat species.

|> I am also aware of Drosophila experiments, but again I do not know if there
|> are any results relevant to my question.

There was one claim for breeding a new species of Drosophila, but closer study
showed that the experiment had started with an undiagnosed pair of sibling
species.

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