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From: J.M.Spencer@newcastle.ac.uk (J.M. Spencer)
Newsgroups: rec.pets,sci.bio
Subject: Re: What is a species?
Keywords: artificial selection makes species identity meaningless
Message-ID: <1990Feb8.100425.16932@newcastle.ac.uk>
Date: 8 Feb 90 10:04:25 GMT
References: <2495@leah.Albany.Edu>
Sender: news@newcastle.ac.uk
Distribution: rec.pets sci.bio
Organization: Computing Laboratory, U of Newcastle upon Tyne, UK NE17RU
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In article <2495@leah.Albany.Edu> gmr044@leah.Albany.Edu (Gregg Recer) writes:
>
>
>In article  <2285@uwm.edu>  debbie@csd4.csd.uwm.edu (Debbie Forest)
>writes:
>
>
>>yes, all dogs are the same species.  but why then aren't wolves in the
>>species too, since dogs and wolves can breed.
I believe that the domestic dog is a *sub-species*.  (Correct me
if I'm wrong).
>
>
>I don't know from what wild species domestic dogs were derived, but
>even if it wasn't wolves dogs might still be able to breed with wolves
>and produce viable offspring.  
It *was* the wolf.
>However, those offspring would then be
>infertile.  This same kind of mating barrier occurs in the
>horse/donkey/mule system. 
I'm not convinced that a dog-wolf cross *would* be infertile.  Do
you have any references?  I saw an ITV documentary regarding Italian 
feral dogs interbreeding with wolves, and as I recall, their 
concern was that hybrids *were* fertile.  What is the inheritance
hierarchy of the horse and mule (I don't know?).  Is one inherited
from the other, as with wolves and dogs.  If not, then you are not
comparing like with like.
>
>Some general remarks:
>
>In many cases, including dogs and cats, a large number of breeds or
>varieties have been produced via artificial selection from a single
>wild species.  In some cases, such as the St. Bernard/Chihuahua
>example a mating barrier has been established via artificial
>selection.  
I don't buy this.  Both *breeds* belong to the same *species*.
Therefore they carry the same genes, right?  Therefore, in theory
at least, they should be able to breed.  Unless you are meaning
that they *physically* couldn't manage it?  If you do, then that
has nothing to do with genetics/species, does it?

>In a sense this mimics the process of speciation in
>natural populations when geographical barriers separate a population
>into two sub-populations and then
>morphological/physiological/behavioral/other variations develop
>between the two sub-populations which eventually render them unable
>to successfully interbreed.  However, by domesticating a wild species
>via artificial selection the domesticated breeds are effectively
>removed from the evolutionary and phylogenetic history of the species
>from which they were derived, in my view, and so asking if they are a
>new species or if several new species have been created is an
>irrelevant question. 
>
>
>
>Gregg