skip to main content


Search for: All records

Creators/Authors contains: "Medina, Rafael"

Note: When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external site maintained by the publisher. Some full text articles may not yet be available without a charge during the embargo (administrative interval).
What is a DOI Number?

Some links on this page may take you to non-federal websites. Their policies may differ from this site.

  1. Abstract

    Allopolyploids represent a new frontier in species discovery among embryophytes. Within mosses, allopolyploid discovery is challenged by low morphological complexity. The rapid expansion of sequencing approaches in addition to computational developments to identifying genome merger and whole-genome duplication using variation among nuclear loci representing homeologs has allowed for increased allopolyploid discovery among mosses. Here, we test a novel approach to phasing homeologs within loci and phasing loci across subgenomes, or subgenome assignment, called Homologizer, in the family Funariaceae. We confirm the intergeneric hybrid nature of Entosthodon hungaricus, and the allopolyploid origin of Physcomitrium eurystomum and one population of Physcomitrium collenchymatum. We also reveal that hybridization gave rise to Physcomitrium immersum, as well as to yet unrecognized lineages sharing the phenotype of Physcomitrium pyriforme and Physcomitrium sphaericum. Our findings demonstrate the utility of our approach when working with polyploid genomes, and its value in identifying progenitor species using target capture data.

     
    more » « less
  2. Introduction. Physcomitrium eurystomum is rare in Europe and threatened with extinction. This study investigates its status and ecology in Britain. Methods. A detailed search was made for P. eurystomum at all sites where it has been reported in Britain, plus four other locations nearby. Geographic coordinates of colonies were recorded with GPS units and used to derive counts of occupied Ordnance Survey (OS) grid cells at resolutions of 1, 10 and 100 m. DNA barcoding was used to help identify non-fruiting plants. Habitat and community composition were recorded by relevés. Results. In this study Physcomitrium eurystomum was found at five locations, one in Hertfordshire and four in West Norfolk, and occupied 109 OS 1 m grid cells. A small pond in West Norfolk (Wicken Pond) supported the majority (61%) of the population. DNA barcoding helped confirm its occurrence at Wilstone Reservoir (Hertfordshire), at which it was thought extinct. The moss occured exclusively within the drawdown zone of seasonally fluctuating freshwater bodies, both natural and artificial. Vegetation was dominated by vascular plants, most frequently Agrostis stolonifera, Persicaria lapathifolia, Ranunculus sceleratus, Rorippa palustris and Stellaria aquatica. Soil pH varied from strongly acidic to slightly alkaline. Conclusions. Unsuccessful searches of five sites with historic records raises concern for the species. The significant importance of Wicken Pond has not been recognised previously and suggests statutory protection of the site is warranted. The non-native and invasive Crassula helmsii is a major risk to P. eurystomum at sites in Britain and elsewhere in Europe. 
    more » « less
  3. Abstract

    Selection on spore dispersal mechanisms in mosses is thought to shape the transformation of the sporophyte. The majority of extant mosses develop a sporangium that dehisces through the loss of an operculum, and regulates spore release through the movement of articulate teeth, the peristome, lining the capsule mouth. Such complexity was acquired by the Mesozoic Era, but was lost in some groups during subsequent diversification events, challenging the resolution of the affinities for taxa with reduced architectures. The Funariaceae are a cosmopolitan and diverse lineage of mostly annual mosses, and exhibit variable sporophyte complexities, spanning from long, exerted, operculate capsules with two rings of well‐developed teeth, to capsules immersed among maternal leaves, lacking a differentiated line of dehiscence (i.e., inoperculate) and without peristomes. The family underwent a rapid diversification, and the relationships of taxa with reduced sporophytes remain ambiguous. Here, we infer the relationships of five taxa with highly reduced sporophytes based on 648 nuclear loci (exons complemented by their flanking regions), based on inferences from concatenated data and concordance analysis of single gene trees.Physcomitrellopsisis resolved as nested within one clade ofEntosthodon.Physcomitrellas. l., is resolved as a polyphyletic assemblage and, along with its putative relativeAphanorrhegma, nested withinPhyscomitrium. We propose a new monophyletic delineation ofPhyscomitrium, which accommodates species ofPhyscomitrellaandAphanorrhegma. The monophyly ofPhyscomitriums. l. is supported by a small plurality of exons, but a majority of trees inferred from exons and their adjacent non‐coding regions.

     
    more » « less