Abstract Detail

Comparative Genomics/Transcriptomics

Conti, Elena [1], Potente, Giacomo [2], Narjes, Yousefi [2], Keller, Barbara [2].

Comparative genomics offers new insights into the evolution of the heterostyly supergen.

The floral dimorphism known as heterostyly has attracted the attention of botanists since Darwin’s seminal studies on Primula. Heterostylous taxa of Primula comprise two different types of plants with distinct floral morphs characterized by reciprocally placed sexual organs. Long-styled flowers have high stigmas and low anthers; short-styled flowers have low stigmas and high anthers. Additionally, a heteromorphic incompatibility system typically prevents self- or intra-morph fertilization. Darwin proposed that heterostyly promotes cross-fertilization via disassortative pollination, thus avoiding the harmful effects of self-fertilization, a view generally confirmed by subsequent genetic analyses. Recent genomic studies in Primula have shown that the genetic control of heterostyly depends on five genes clustered in the heterostyly supergene, known as the S locus. Despite the numerous genetic, morphological, and reproductive studies on heterostyly, the evolutionary origins of the S locus remained unknown. Did the S locus evolve through a single, large duplication followed by loss of intervening genes or through multiple, asynchronous gene duplications followed by translocations? By generating a highly contiguous, chromosome-scale, haplotype-phased assembly of the Primula veris genome and performing comparative genomic analyses across Ericales we demonstrated that the S locus evolved according to the latter model. Current studies are aimed at testing whether the same genomic architecture of the Primula S locus is also found in Hottonia and Androsace, which evolved heterostyly independently. Thus, Primulaceae represent an ideal system to compare convergent evolution at the phenotypic vs. genotypic levels.

1 - Department Of Systematic And Evolutionary Botany, Zollikerstrasse 107, Zürich, 8008, Switzerland
2 - University of Zurich, Department of Systematic and Evolutionary Botany, Zollikerstrasse 107, Zurich, 8008, Switzerland

Keywords:
Supergene
convergent evolution
Primulaceae
reproductive biology
Heterostyly
Floral dimorphism
floral evolution
Gene duplication
Suppression of recombination.

Presentation Type: Oral Paper
Number: CGT5005
Abstract ID:1266
Candidate for Awards:None