I’m not aware of any such example. I’m not an expert, so could be wrong and the terminology in the following could wrong, but just to give you an idea:
If the species are genetically too different, it can already be a problem that the reproduction organs don’t match. For example, human sperm can’t even try to inseminate a chicken egg, because the egg shell simply blocks it.
This is a fairly obvious example, but even at microscopic scale, the sperm may not be compatible with the egg cell.
Then you’ve got the problem that the DNA needs to be combined in some fashion. If you’ve got a different number of chromosomes, that will cause problems.
But even if a successful insemination were to take place and a fetus develops, there’s a very high chance that the gene combination of e.g. a human and a chicken just does not develop into something that can survive. It might have a chicken heart in a human-sized body and just can’t pump enough blood to survive. All kinds of things like that can go wrong.
In general, nature is messy. It does not care about our definition of a species. But yeah, the chance of inter-species offspring is just very low when the species are very different.
I’m not aware of any such example. I’m not an expert, so could be wrong and the terminology in the following could wrong, but just to give you an idea:
If the species are genetically too different, it can already be a problem that the reproduction organs don’t match. For example, human sperm can’t even try to inseminate a chicken egg, because the egg shell simply blocks it.
This is a fairly obvious example, but even at microscopic scale, the sperm may not be compatible with the egg cell.
Then you’ve got the problem that the DNA needs to be combined in some fashion. If you’ve got a different number of chromosomes, that will cause problems.
But even if a successful insemination were to take place and a fetus develops, there’s a very high chance that the gene combination of e.g. a human and a chicken just does not develop into something that can survive. It might have a chicken heart in a human-sized body and just can’t pump enough blood to survive. All kinds of things like that can go wrong.
In general, nature is messy. It does not care about our definition of a species. But yeah, the chance of inter-species offspring is just very low when the species are very different.
While this doesn’t change the viability of humans fertilizing chickens, chicken sperms doesn’t have some special ability to penetrate the egg shell, the shell is formed well after the egg is fertilized.
Ah, that does make a lot of sense, yeah. Thanks!