Abstract Detail

Recent Topics Posters

Baiakhmetov, Evgenii [1], Ryzhakova, Daria [2], Gudkova, Polina D. [2], Nobis, Marcin [1].

Evidence for extensive hybridisation and past introgression events in feather grasses using genome-wide SNP genotyping.

The proper identification of feather grasses in nature is often limited due phenotypic variability and high morphological similarities between many species. Among plausible factors influencing this issue are hybridisation and introgression recently detected in the genus. Nonetheless, to date, only a bounded set of taxa were investigated using integrative taxonomy combining morphological and molecular data. Here, we report the first big-scale study on five feather grass species across several hybrid zones in Russia and Central Asia. In total, 302 specimens were sampled in the field and classified based on the current descriptions of these taxa. They were then genotyped with high density genome-wide markers and measured based on a set of morphological characters to delimitate species and assess levels of hybridisation and introgression. Moreover, we tested species for past introgression and estimated divergence times between them. Our findings demonstrated that 250 specimens represent five distinct species: S. baicalensis, S. capillata, S. glareosa, S. grandis and S. krylovii. The remaining 52 individuals provided evidence for the extensive hybridisation between S. capillata and S. baicalensis, S. capillata and S. krylovii, S. baicalensis and S. krylovii, as well as to a lesser extent between S. grandis and S. krylovii, S. grandis and S. baicalensis. We detected past reticulation events between S. baicalensis, S. krylovii, S. grandis and inferred that diversification within species S. capillata, S. baicalensis, S. krylovii and S. grandis started ca. 130–96 kya. In addition, the assessment of genetic structures revealed signs of contemporary gene flow between populations across species from the section Leiostipa, despite significant distances between some of them. Lastly, we concluded that only 5 out of 52 hybrid taxa were properly identified solely based on morphology. Our results support the hypothesis that hybridisation is an important mechanism driving evolution in Stipa. As an outcome, this phenomenon complicates identification of hybrid taxa in the field using morphological characters alone. Thus, integrative taxonomy seems to be the only reliable way to properly resolve the phylogenetic issue of Stipa. Moreover, we believe that feather grasses may be a suitable genus to study hybridisation and introgression events in nature.

1 - Jagiellonian University , Institute of Botany , Gronostajowa 3, Krakow, Lesser Poland, 30-387, Poland
2 - National Research Tomsk State University, Research laboratory 'Herbarium', Lenin 36 Ave., Tomsk, 634050, Russia

Keywords:
feather grasses
hybridisation
Introgression
Integrative taxonomy
genome-wide genotyping
DArTseq
divergence time estimation
population genetic structure.

Presentation Type: Recent Topics Poster
Session: P1, Recent Topics Posters
Location: Virtual/Virtual
Date: Thursday, July 22nd, 2021
Time: 5:00 PM(EDT)
Number: P1RT004
Abstract ID:1373
Candidate for Awards:None