Abstract Detail

Phylogenomics

Skibicki, Sam [1], Barrett, Craig [2].

Plastid genomes provide resolution and support for phylogenetic relationships in Zinniinae (Asteraceae; Heliantheae).

Herbarium specimens contain a wealth of information, and can be leveraged for high throughput genomic sequencing in systematic studies. This is especially relevant for clades that contain rare, difficult-to-collect, or even extinct species. One such clade that displays these features is the subtribe Zinniinae. The Zinniinae are a subtribe of seven genera and about 54 species of New World subshrubs, perennials, and annuals with highly variable chromosome counts, and it includes two economically and ecologically important genera, Echinacea and Zinnia. However, little is known about their placement in the tribe. Their subgeneric relationships have been posited using purely morphological analysis and are primed for study using molecular methods. They range from the temperate regions of North and South America, but are most diverse in arid regions of Mexico. Apart from Echinacea, the subtribe is understudied and most genera within have limited genetic sequences publicly available. Further, species and generic level relationships delimitations are unclear. We hypothesize that the Zinniinae is monophyletic and also expect to find either support for current subgeneric delimitations or uncover new subgeneric cladogenesis that eluded purely morphological researchers. We have generated a robust phylogenetic hypothesis for this clade using ‘herbariomics’, genomic libraries, Illumina sequencing, de-novo assembly pipelines, and Maximum likelihood approaches to tree building. Leaf tissue samples were taken from 60 pressed and dried plants stored at herbaria, with specimens dating back to 1930. Dual-indexed libraries were created as an input for genome skimming. Sequences were obtained through the Illumina HiSeq platform. Complete plastomes were assembled using the Fast-Plast pipeline. A preliminary tree was created using a subset of our samples (18), combined with over 130 publicly available plastid genomes from across the family Asteraceae. We recovered highly resolved relationships and bootstrap values of 100 for: 1) the Zinniinae as monophyletic, 2) monophyly of Echinacea, Heliopsis, Sanvitalia, and Zinnia and 3) splits in the largest and namesake genus, Zinnia, that dispute current subtribal delimitations. As a future direction, this tree will be used to study speciation rates, biogeographic patterns, and chromosome number evolution in regards to arid adaptation in this clade.

1 - West Virginia University, Biology, 53 Campus Drive, Morgantown, WV, 26506, USA
2 - West Virginia University, Biology, 52 Campus Dr, Morgantown, WV, 26506, USA

Keywords:
phylogenomics
Asteraceae
Herbariomics
Plastid genomes
Zinniinae.

Presentation Type: Oral Paper
Session: PHYLOIII, Phylogenomics III
Location: Virtual/Virtual
Date: Thursday, July 22nd, 2021
Time: 10:15 AM(EDT)
Number: PHYLOIII002
Abstract ID:519
Candidate for Awards:None