liquid

Hi everyone, been away for a while because I only have net access at work. Back next summer as promised. In the meantime, here is a little tidbit for you; hope I am not repeating it if it has already been covered.

It appears <a href="http://news.bbc.co.uk/2/hi/science/nature/2399773.stm" target="_blank">here</a> that a mule (A donkey-horse hybrid) has had some sort of chromosomal mutation allowing it to produce offspring.

For those of you with biological knowledge (i.e. most people here!) the implications are pretty, clear, so I won't go into too much detail as I don't have the time. I would be grateful if one of the bio grads here goes into it a little bit though.

Suffice to say that this is, according to some species definitions, an instance of speciation, and macroevolution at that (across a species barrier). It certainly proves that this kind of fertile hybrid speciation is possible, although I should mention that it's been seen plenty of times in plants. But to see it in a mammal is pretty interesting.

But of course, it IS neither.

Unfortunately, it was not possible to find out if the extra/lesser chromosome was a mutation in the mother or child. If in the mother, it may be possible to develop a population. It would also be nice to find out if the child is fertile.

Mageth

Just for information, there are a few other documented cases where a jenny (female mule) has conceived and given birth. There are no documented cases, IIRC, where a jack (male mule) has sired a foal (although they're almost always gelded, so...).

Corwin

Mules aren't always sterile... never have been.

In the few cases where they've had a fertile mule, they've bred them back to either a horse or a donkey...

But the point is MOST mules are sterile... not all.

The Sound of Dogs Barking

I would also like some input on this:

It has been shown numerous times that inter-generic hybrids in snakes produce fertile offspring. The first that comes to mind is the so-called "jungle corn", a cross of the california kingsnake, Lampropeltis getula californiae, and the corn snake, elaphe guttata.

Does this indicate
A. The definition of "species" needs to be better defined;
B. The animals in question are much more related than current taxonomy suggests;
C. The current definition of species is A-OK, because in nature the two species are "reproductively isolated" because of location (but then, I've heard of "natural" hybrids)
or D. (fill in the blank)

Doubting Didymus

The answer is mostly A, but there is sod all you can really do about the definition of species. It might seem clear cut to a layman, but if you do a course in introductory biology one of the first things you learn is that the definition for species is screwed, and can never really be perfect. Taxonomists and phylogeneticists just have to cope with these things as they come.

However, there is a handy little term called 'cryptid' that you are allowed to brandy about when you get in trouble.

Corwin

Well mules aren't the only ones either....

Ligers have been bred before. Not often, but it's happened. Not yet with Tigrons tho... (either that or the other way around... I forget.)

Mageth

Ligers, not Tigrons, and Mules, oh my!

Doubting Didymus

Yes, but were they fertile? That's a far more important step than just hybridising. Most hybrids can never produce a population.

Corwin

Let me clarify, there have been mules that have been mated to donkeys, as well as either ligers or tigrons that have been mated to either lions or tigers. (I forget the specifics... been a while. I THINK it was a liger mated to a tiger. Yes offspring are produced.)

'Sterile' hybrid is a relative term.... MOST of them are sterile. But every so often you find one that's fertile.

scigirl

Exactly, which to me is perfect evidence of evolution, and a refutation of special creation. If all the kinds were created separately, why such amgiguity, as if the species tend to "blend" into other species? Could it be. . . because they weren't separately created but instead evolved?

scigirl