Abstract Detail

Phylogenomics

Renner, Susanne S. [1], Bai, Wei-Ning [2], Zhang, Da-Yong [3].

Whom to trust wehn a microsynteny- and gene-content-based topology differs drastically from sequenced-based trees: Juglandaceae as a test case.

Most flowering plants have experienced whole-genome duplications (WGD) during their evolution, often because polyploidy allows hybrid fertility by restoring proper chromosome pairing. Depending on the subsequent evolution of the duplicated chromosomes, gene phylogenies may not reflect the species tree. While this problem has been understood for 25 years, the extent to which phylogenies based on DNA alignments may have misled analyses is unknown, especially under introgression. The Juglandaceae, an ancient family of ten species-poor genera, are known to have undergone a WGD and ancient hybridizations in Juglans. We assembled, or downloaded from public databases, chromosome-level genomes of seven species from five genera representing the deepest divergences within Juglandaceae, with several Fagales as outgroups, and carried out analyses using alignment-, microsynteny-, and gene-content-based tree inference. Results show that the WGD involved all Juglandaceae, with microsynteny- and gene-content-based phylogenies pointing to an ancient hybridization between two extinct or unsampled progenitors (subgenomes) nested within Myricaceae. Genus relationships in the new phylogeny differ strongly from those obtained in numerous studies over the past 20 years, requiring exploration of the sensitivity of these results to underlying assumptions. That will be the topic of this talk.

1 - 7191 Washington Ave., Saint Louis, MO, 63130, United States
2 - Beijing Normal University, College of Life Sciences, Beijing, 100093, China
3 - Beijing Normal University, College of Life Sciences, 100093, China

Keywords:
allopolyploidy
DNA repair
gene-content-based tree
whole-genome duplication
introgression.

Presentation Type: Oral Paper
Number: PHYLO I002
Abstract ID:37
Candidate for Awards:None