Biology subjects

Kinosian, S. P.

Publications and source records attributed to Kinosian, S. P..

3 recordsLinked to original sources

bioRxiv2024

Ancient polyploidy and low rate of chromosome loss explain the high chromosome numbers of homosporous ferns

A longstanding question in plant evolution is why ferns have many more chromosomes than angiosperms. The leading hypothesis proposes that ferns have ancient polyploidy without chromosome loss or gene deletion to explain the high chromosome numbers of ferns. Here, we test this hypothesis by estimating ancient polyploidy frequency, chromosome evolution, protein evolution in meiosis genes, and patterns of gene retention in ferns. We found similar rates of paleopolyploidy in ferns and angiosperms from independent phylogenomic and chromosome number evolution analyses, but lower rates of chromosome loss in ferns. We found elevated evolutionary rates in meiosis genes in angiosperms, but not in ferns. Finally, we found some evidence of parallel and biased gene retention in ferns, but this was comparatively weak to patterns in angiosperms. This work provides genomic evidence supporting a decades-old hypothesis on fern genome evolution and provides a foundation for future work on plant genome structure.

evolutionary biology↗

bioRxiv2020

Revealing the evolutionary history of a reticulate polyploid complex in the genus Isoëtes

O_LIPolyploidy and hybridization are important processes in the evolution of spore-dispersed plants. Few studies, however, focus these dynamics in heterosporous lycophytes, such as Isoetes, where polyploid hybrids are common and thought to be important in the generation of their extant diversity. We investigate reticulate evolution in a complex of western North American quillworts (Isoetes) and provide insights into the evolutionary history of hybrids, and the role of polyploidy in maintaining novel diversity. C_LIO_LIWe utilize low copy nuclear markers, whole plastomes, restriction site-associated DNA sequencing, cytology, and reproductive status (fertile or sterile) to investigate the reticulate evolutionary history of western North American Isoetes. C_LIO_LIWe reconstruct the reticulate evolutionary history and directionality of hybridization events in this complex. The presence of high level polyploids, plus frequent homoploid and interploid hybridization suggests that there are low prezygotic reproductive barriers in this complex, hybridization is common and bidirectional between similar--but not divergent--cytotypes, and that allopolyploidization is important to restore fertility in some hybrid taxa. C_LIO_LIOur data provide five lines of evidence suggesting that hybridization and polyploidy can occur with frequency in the genus, and these evolutionary processes may be important in shaping extant Isoetes diversity. C_LI

evolutionary biology↗

bioRxiv2020

Cryptic diversity in the model fern genus Ceratopteris (Pteridaceae)

Cryptic species are present throughout the tree of life. They are especially prevalent in ferns, because of processes such hybridization, polyploidy, and reticulate evolution. In addition, the morphological simple body plan of ferns limits phenotypic variation and makes it difficult to detect crypic species in ferns without molecular work. The model fern genus Ceratopteris has long been suspected to harbor cryptic diversity, specifically in the highly polymorphic C. thalictroides. Yet no studies have included samples from throughout the pan-tropical range of Ceratopteris or utilized genomic sequencing, making it difficult to assess the full extent of cryptic variation within this genus. Here, we present the first multilocus phylogeny of the genus using reduced representation genomic sequencing (RADseq) and examine population structure, phylogenetic relationships, and ploidy level variation. We recover similar species relationships found in previous studies, find support for a named cryptic species as genetically distinct, and identify a novel putative species from within C. thalictroides sensu latu in Central and South America.

plant biology↗