Polyploidy is a condition in which an organism has more than two complete sets of chromosomes in every cell (i.e. > diploid)
- Autopolyploidy occurs when a polyploid offspring is derived from a single parental species (usually via self fertilisation)
- Allopolyploidy occurs when a polyploid offspring is derived from two distinct parental species
Allopolyploidy
- Normally different species cannot interbreed because they have different chromosome numbers and cannot form diploid pairs
- Offsprings produced by such unions are typically sterile due to this uneven chromosome pairing
- If cytokinesis fails to occur in one of the gametes, the hybrid offspring will have paired chromosomes from that parent species
- If the hybrid interbreeds with a member of the other parent species, all chromosomes from both parent species will be paired
- The resulting offspring will now be fertile and have the combined chromosome composition of both parental species
Allopolyploids are more prevalent than autopolyploids as they do not show polysomic inheritance and have better fertility rates
Allopolyploidy
