Abstract Detail

Phylogenomics

Kandziora, Martha [1], Gorospe, Juan Manuel [2], Sklenar, Petr [3], Fer, Tomas [4], Kolar, Filip [4], Schmickl, Roswitha [4].

Implausibly strong gene tree discordance in a radiating plant group that seems to lack hybrids and neopolyploids? A case study of high-Andean Loricaria (Asteraceae).

Gene tree discordance is common in phylogenomic datasets and sometimes so strong that it seems implausible. Evolutionary processes resulting in gene tree discordance are incomplete lineage sorting (ILS), hybridization and gene duplication. As species tree methods do not accommodate for all these processes simultaneously, a combination of multiple approaches is needed to disentangle them. We chose the high-Andean Asteraceae genus Loricaria (14 species out of ca. 20 species) to shed light on the potential sources of gene tree discordance. We generated a species tree hypothesis based on hundreds of nuclear loci, using Hyb-Seq, and a plastome phylogeny obtained from the off-target reads. We observed high gene tree discordance, which we found implausible at first sight, because the genus did not show any strong evidence of hybridity in previous studies. However, the low genetic differentiation of the species between the different Andean cordilleras could be indicative of a substantial amount of gene flow between populations, although it needs to be tested if it is gene flow after secondary contact (i.e. hybridization). Despite the absence of neopolyploids in the genus, paralogy may occur, resulting from the ancient hexapolyploidization event shared by all Asteraceae. The most obvious evolutionary process underlying gene tree discordance in Loricaria is ILS, as the genus is of relatively young age and radiating in the tropical high Andes. In this study, we use various phylogenomic analyses (trees and networks), including recently developed ParalogWizard approach that identifies paralogs and uses them for phylogenetic reconstruction, in combination with species delimitation and the ABBA-BABA test to disentangle the various evolutionary processes leading to gene tree discordance in the genus Loricaria.

1 - Department Of Botany, Faculty Of Science - Charles University, Benatska 2, Prague, PR, 12800, Czech Republic
2 - Faculty Of Science, Charles University, Department Of Botany, Benátská 433/2, Prague, PR, 128 01, Czech Republic
3 - Charles University, Department Of Botany, BENATSKA 2, PRAHA, PR, 12801, Czech Republic
4 - Charles University, Department Of Botany, Faculty Of Science, Benatska 2, Prague, 12800, Czech Republic

Keywords:
none specified

Presentation Type: Oral Paper
Session: PHYLOII, Phylogenomics II
Location: Virtual/Virtual
Date: Tuesday, July 20th, 2021
Time: 3:15 PM(EDT)
Number: PHYLOII002
Abstract ID:346
Candidate for Awards:None