Awards of JSE Outstanding Papers (2021)

In 2015, Journal of Systematics and Evolution (JSE) established the Awards of JSE Outstanding Papers to recognize the papers published in JSE with important impact in systematics and evolution (Ge & Wen, 2015). Two Outstanding Papers and two Outstanding Papers by Young Investigators have been awarded each year since 2018. The selection of the awards was based on votes and assessments from all 17 editors of the journal with the consideration of the citations (data from Clarivate Web of Science) and the perceived impact on systematics and evolution. The winners of the Awards will receive a certificate and a prize of $800 (JSE Outstanding Papers) or $500 (JSE Outstanding Papers by Young Investigators) (Ge & Wen, 2021, 2022). Here we are delighted to announce the recipients of the awards for the 2021 papers and highlight the significance of the four awarded papers.

Roalson et al. A framework infrageneric classification of Carex (Cyperaceae) and its organizing principles

The genus Carex L. (Cyperaceae) is widely distributed across continents and represents one of the largest genera in angiosperms, including about 2000 species. Although taxonomists continue to use subgenera and sections in Carex classification, the current understanding of phylogenetic relationships in this genus is not yet sufficient for a global reclassification of the genus within a Linnean infrageneric framework because numerous phylogenetic studies have demonstrated that most subgenera and sections in the genus are polyphyletic. In this study, Roalson et al. (2021) presented a hybrid classification framework of Carex to reflect the current state of our knowledge using a combination of informally named clades and formally named infrageneric groups. Based on an order corresponding to a linear arrangement of the clades on a ladderized phylogeny, the authors organized Carex into six subgenera, which were further subdivided into 62 formally named sections plus 49 informal groups. As the authors remarked, as many as 113 species were not placed in a clade with any confidence in this study and difficulties remained for untangling intricate nomenclature and identifying types for the many available sectional names. Despite these challenges, the proposed infrageneric classification of Carex will serve as a roadmap for better organizing our understanding of phylogeny, identifying species groups and stimulating further studies of this important genus.

Larridon et al. A new classification of Cyperaceae (Poales) supported by phylogenomic data

As the third largest monocot family with great economic and ecological importance, Cyperaceae (sedges) represent an ideal model family to study various questions in evolutionary biology. Despite considerable advances in molecular phylogenetic studies at the family level, evolutionary relationships at the tribal and generic levels remain largely unresolved due to insufficient sampling of some genera and conflicting relationships among major lineages in previous studies. By sampling 361 accessions of Cyperaceae species and 21 accessions representing other families in the order Poales, Larridon et al. (2021) presented the first family-wide phylogenomic study of Cyperaceae based on targeted sequencing using the Angiosperms probe kit. Their results supported the majority of previously recognized suprageneric groups, and placed previously unplaced genera in the family phylogeny for the first time. Based on the resolved phylogenetic framework, the authors proposed a new classification for the family at the tribal, subtribal, and generic levels, with a taxonomic treatment including identification keys and diagnoses for the two subfamilies, 24 tribes, and also 10 subtribes, and taxonomic information on the 95 genera recognized. Moreover, this study implicated that the high-throughput technique—targeted sequencing (Weitemier et al., 2014; Zimmer & Wen, 2015) is able to sequence historical herbarium specimens with poor DNA quality and thus might be widely applicable to molecular evolutionary studies in plants (also see Wang et al., 2021; Gallego-Narbón et al., 2022).

Abdullah et al. Correlations among oligonucleotide repeats, nucleotide substitutions, and insertion–deletion mutations in chloroplast genomes of plant family Malvaceae

Genetic diversity consists of different types of variation or mutations, which are changes at molecular level from a single base pair to alterations of longer DNA sequences and to changes affecting entire chromosomes or even an entire genome. Nucleotide substitutions, insertions–deletions (InDels) and oligonucleotide repeats are major types of mutations and their co-occurrence has less been investigated and remains elusive in terms of organisms and organelle genomes. Based on 19 whole-chloroplast genomes representing 12 genera of Malvaceae (three newly sequenced and 16 publicly available), this study calculated the correlation coefficients among these mutational events at family, subfamily, and genus levels. By defining a correlation coefficient to categorize the extent of correlations among substitutions, InDels and repeats, the authors revealed weak-to-strong correlations among these mutational events and confirmed the co-occurrence of up to 90% of oligonucleotide repeats with substitutions. Abdullah et al. (2021) supported the previous argument that oligonucleotide repeats could be used as a proxy for finding the mutational hotspots. The authors also hypothesized that the correlations among these mutations might be a common characteristic of chloroplast genomes in all plant lineages, which deserves further investigations in various lineages of organisms.

Yao et al. Phylogeny and biogeography of the hollies (Ilex L., Aquifoliaceae)

The holly genus (Ilex, Aquifoliaceae) is a large woody dioecious genus and consists of over 664 species, with many of them being economically important. Despite numerous studies on the phylogeny of this genus, there remains widespread discordance between plastid and nuclear trees, and uncertainties regarding the origin of specific lineages. Based on sequences of two nuclear genes representing 177 species and calibrated using three macrofossil records, Yao et al. (2021) constructed a phylogeny of Ilex and investigated the biogeographic patterns of the genus. They identified five main clades that had a common ancestor in the early Eocene, much earlier than previously hypothesized. They also demonstrated that Ilex originated in subtropical Asia and subsequently colonized the Americas, Australia, Europe and Africa, and that the current near-cosmopolitan distribution reflects a balance between dispersal, diversification and extinction. This work provides an important evolutionary framework for further studies in comparative ecology and evolution using Ilex as a feasible system.

We herein congratulate the winners of the 2021 JSE Awards for their important contributions to systematics and evolution! We also cordially invite colleagues in systematics and evolution to submit their first-rate research papers to JSE and be considered for these awards in the coming years!