I'm debating a creationist and he claims that chromosome number difference causes infertility, always. My understanding is different. However I can't seem to find a good source to reference.
http://www.talkorigins.org/indexcc/CB/CB141.html mentions that if genes can still align reproductions is still possible. Not sure if that really gives definate answer about infertility or fertility of the offspring.
Do you (or, rather, the creationist) by this mean that interbreeding between two species (or other groups) with different chromosome number always result in infertile offspring (or, at least, does so in those cases when offspring is gained at all)?
If the parent organisms have the possibility to either reproduce asexually or by self-fertilization, the offspring need not be infertile regardless of wether the offspring goes through doubling of the hybrid chromosome set or not.
An example of this would be
Lumbriculus variegatus, an annelid I have studied to some extent. It is highly variable in chromosome numbers (although I don't know if this is due to auto- or allopolyploidy, or both), with the highest countable chromosome number being 11-ploid (2n=c.185). After this, the chromosomes are reportedly too small and too many for counting to be at all practical, but do supposedly exist. Still, they seem to manage reproducing pretty well, and are in no way infertile.
(However, it seems that sexual reproduction in
L. variegatus and some of the related species is either incredibly infrequent or simply overlooked in nature, why this is not a very good example.)
So, can anyone help me with a link to a study on this?
I believe I have a copy of that
Hyla versicolor study that is mentioned in the link you posted in your second post at work. If it interests you, I could find it and post a complete reference, as that seems to be missing from the TalkOrigins site.
