Phylogenetic relationships within the Jarava-Pappostipa clade (Pooideae; Stipeae) with emphasis on the population genomics of Jarava neaei and J. psylantha

SANTIAGO MORELLO; SASSONE, AGOSTINA B.; SEDE, S. M.; GIUSSANI, L. M.; STARR, J.

Congreso; BOTANY 2021; 2021

Botanical Society of America, ASPT, IAPT

The New World genus Jarava is widely distributed in South America and consist of 31 species, although as currently defined, it is polyphyletic. Jarava psylantha and J. neaei are sibling species that are sympatric in the southernmost part of the Argentinian Patagonian steppe (ca. 45 °-52 ° South latitude). Both species are closely related to species of Pappostipa in a clade characterized by long-hairy awns that differ in their position. Owing to the limited representation of these South American taxa in phylogenetic studies, their population genetics and interspecific relationships remain unclear. The goal of this study was to assess extant genomic variation, geographic structure, and admixture within and among the species of the Jarava-Pappostipa Clade. For the first time, a phylogenomic analysis was carried out in 40 populations of Jarava psylantha and J. neaei using genome-wide single-nucleotide polymorphism (SNP) data from ddRAD to determine species relationships within their wider clade and to test whether these taxa were good species. Loci were assembled using the ipyRAD pipeline, and the analyses were performed using the ipyrad API toolkit. A total of 98,220 loci were retained for the ingroup after filtering, and a concatenated matrix of 8,778,097 bp was generated. Principal component analysis and a Neighbor-Net network were performed to explore the data. Phylogenetic analyses were performed using RAxML and tetrad. Results were similar for all methods in suggesting that J. psylantha and J. neaei are sisters, reciprocally monophyletic (100% BS), and distantly related to Pappostipa. Bayesian clustering using STRUCTURE indicated high levels of differentiation between populations of each species. Future analyses will focus on the population dynamics of the Jarava species studied.