Abstract Detail

Population Genetics/Genomics

Scott, Alison [1], Kolesnikova, Uliana [1], Novikova, Polina [1].

Genomics of polyploid adaptation and formation in Siberian Arabidopsis lyrata.

Polyploidy is a critical and dynamic evolutionary mechanism with several downstream consequences including genome dominance, gene loss, genome rearrangement, sub- and neo-functionalization of genes, etc. Though polyploids are known to occur more frequently at higher latitudes, Siberia remains largely unexplored with regards to polyploid occurrence. With both live field collections and widely distributed herbarium specimens, we identified previously unknown tetraploid populations of Siberian A. lyrata via genotyping, followed by cytogenetic validation on fresh samples.
To investigate how these Siberian tetraploids are managing their duplicated genomes, we conducted selection scans between diploid and tetraploid populations. These analyses revealed that loci under selection in tetraploid populations include key players in meiosis, e.g. zyp1b, a central component of the synaptonemal complex that is involved in crossover mediation. These genes have been shown to facilitate adaptation to whole genome duplication in A. arenosa and European A. lyrata - putatively via adaptive introgression, but preliminary data suggest that maintenance of standing variation is also important.
We also identified a lineage of diploid Siberian A. lyrata rendered self-compatible due to the breakdown of the S-locus self-incompatibility system. In further investigating this lineage, we discovered that self-compatible accessions cluster strongly with allopolyploid A. kamchatica. Additional evidence from S-haplotypes indicate self-compatible Siberian A. lyrata is a parental lineage to A. kamchatica (which has multiple origins) suggesting that self-compatibility also facilitates the emergence of allopolyploid taxa.Taken together, these observations of the adaptation and formation of polyploids in Siberian A. lyrata change the story of polyploid evolution in Arabidopsis and provide opportunity to further our understanding of polyploid evolution as a whole.

1 - Max Planck Institute for Plant Breeding Research, Dept. of Chromosome Biology, Carl-von-linne-weg 10, Köln, NRW, 50829, Germany

Keywords:
polyploid
whole genome duplication
siberia
meiosis
arabidopsis.

Presentation Type: Oral Paper
Number: PGG5003
Abstract ID:416
Candidate for Awards:None