Dissecting 2 Meiotic Mutations (dmc1 and asy1) in Artificial Autopolyploid Arabidopsis thaliana

Polyploidization affects chromosomal behavior especially during meiosis. After the establishment of polyploid plants, autopolyploids featured with polysomic inheritance show numerous multivalents such as trivalents and quadrivalents, rather than unique bivalent formation, but allopolyploids usually exhibit diploid-like features that are characterized with disomic inheritance. In the present study, we aimed to analyze meiotic chromosomal behavior in 2 specific meiotic mutations (dmc1 and asy1), and attempted to seek cytological interpretation of polyploidy dominance in flowering plants. The results show tetraploids dmc1 and asy1 display reduced fertility but are rather fertile in comparison with diploid mutants (dmc1 and asy1). The cytological analyses demonstrate that tetraploid asy1 has a higher frequency of residual chiasmata and/or bivalent formation than those of diploids, although tetraploid dmc1 did not show improved meiotic progression after polyploidization. These results to some extent indicate that polyploidy can potentially alleviate lethal effects brought by some mutations via more aneuploidy propagated in plant reproductive life cycles.