A fully resolved backbone phylogeny reveals numerous dispersals and explosive diversifications throughout the history of Asteraceae

Abstract

The sunflower family, Asteraceae, comprises 10% of all flowering plant species and displays an incredible diversity of form. Asteraceae are clearly monophyletic, yet resolving phylogenetic relationships within the family has proven difficult, hindering our ability to understand its origin and diversification. Recent molecular clock dating has suggested a Cretaceous origin, but the lack of deep sampling of many genes and representative taxa from across the family has impeded the resolution of migration routes and diversifications that led to its global distribution and tremendous diversity. Here we use genomic data from 256 terminals to estimate evolutionary relationships, timing of diversification(s), and biogeographic patterns. Our study places the origin of Asteraceae at ∼83 MYA in the late Cretaceous and reveals that the family underwent a series of explosive radiations during the Eocene which were accompanied by accelerations in diversification rates. The lineages that gave rise to nearly 95% of extant species originated and began diversifying during the middle Eocene, coincident with the ensuing marked cooling during this period. Phylogenetic and biogeographic analyses support a South American origin of the family with subsequent dispersals into North America and then to Asia and Africa, later followed by multiple worldwide dispersals in many directions. The rapid mid-Eocene diversification is aligned with the biogeographic range shift to Africa where many of the modern-day tribes appear to have originated. Our robust phylogeny provides a framework for future studies aimed at understanding the role of the macroevolutionary patterns and processes that generated the enormous species diversity of Asteraceae.

A chromosome‐scale draft sequence of the Canada fleabane genome

“…Future efforts should focus on sequencing of additional biotypes to examine the diversity of the species and, in turn, provide clues to explain the high phenotypic variability that characterize weeds in general. The genome sequence reported here also represents additional knowledge for the study of evolution in the Asteraceae, a family that represents 10% of flowering plant diversity, including numerous weeds and crops …”

An empirical assessment of a single family‐wide hybrid capture locus set at multiple evolutionary timescales in Asteraceae

“…However, phenomena such as whole genome duplications (WGDs), ancestral and recent hybridization, and rapid radiations remain a challenge even when using HTS data (Straub et al., ; Tiley et al., ). Asteraceae, the largest flowering plant family (10–12% of all flowering plants, 25,000–33,000 species; Mandel et al., , ), serves as a good example for the aforementioned challenges (Fig. ).…”

“…() published a probe set designed for hybrid capture in combination with genome skimming, using HTS (hereafter Hyb‐Seq; Weitemier et al., ), that targets 1061 nuclear loci that are potentially low‐copy and orthologous across the Asteraceae family, based on conserved markers (hereafter referred to as the conserved orthologous set [COS]; Mandel et al., ). The COS locus set (MyBaits COS Compositae/Asteraceae1kv1; Arbor Biosciences, Ann Arbor, Michigan, USA) has been demonstrated to provide a well‐resolved family backbone, with high resolution at the subfamily and tribal levels (Mandel et al., , ). The locus set has also helped to disentangle relationships among complex and diverse genera within tribe Cardueae (Herrando‐Moraira et al., , ).…”

“…The locus set has also helped to disentangle relationships among complex and diverse genera within tribe Cardueae (Herrando‐Moraira et al., , ). Robust divergence time estimations across the family can now be performed (Mandel et al., ). However, there is a need for a critical assessment of the applicability of the Asteraceae COS locus set across multiple taxonomic levels (i.e., tribes, genera, species), including tests for the proportions of parsimony informative (PI) loci.…”

Morphological and molecular analyses of South American Microliabum (Compositae, Liabeae, Paranepheliinae) and reinstatement of Austroliabum

“…We thank the Administración de Parques Nacionales for collection permits to the Parque Nacional Calilegua (2007 and. When this paper was in press, we received the sad news of the passing of our colleague and friend Vicki Ann Funk (1947Funk ( -2019, who made many important scientific contributions to the systematics of tribe Liabeae. Rest in peace.…”