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    High-throughput sequencing for algal systematics
    Oliveira, MC ; Repetti, SI ; Iha, C ; Jackson, CJ ; Diaz-Tapia, P ; Lubiana, KMF ; Cassano, V ; Costa, JF ; Cremen, MCM ; Marcelino, VR ; Verbruggen, H (TAYLOR & FRANCIS LTD, 2018-01-01)
    In recent years, the use of molecular data in algal systematics has increased as high-throughput sequencing (HTS) has become more accessible, generating very large datasets at a reasonable cost. In this perspectives paper, our goal is to describe how HTS technologies can advance algal systematics. Following an introduction to some common HTS technologies, we discuss how metabarcoding can accelerate algal species discovery. We show how various HTS methods can be applied to generate datasets for accurate species delimitation, and how HTS can be applied to historical type specimens to assist the nomenclature process. Finally, we discuss how HTS data such as organellar genomes and transcriptomes can be used to construct well-resolved phylogenies, leading to a stable and natural classification of algal groups. We include examples of bioinformatic workflows that may be applied to process data for each purpose, along with common programs used to achieve each step. We also discuss possible strategies and the new skill set that will be required to fully embrace HTS as a part of algal systematics, along with considerations of cost and experimental design. HTS technology has revolutionized many fields in biology, and will certainly do the same in algal systematics.
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    The golden paradox - a new heterokont lineage with chloroplasts surrounded by two membranes
    Wetherbee, R ; Jackson, CJ ; Repetti, SI ; Clementson, LA ; Costa, JF ; van de Meene, A ; Crawford, S ; Verbruggen, H ; Graham, L (WILEY, 2019-04)
    A marine, sand-dwelling, golden-brown alga is described from clonal cultures established from a high intertidal pool in southeastern Australia. This tiny, unicellular species, which we call the "golden paradox" (Chrysoparadoxa australica gen. et sp. nov.), is benthic, surrounded by a multilayered cell wall and attached to the substratum by a complex adhesive plug. Each vegetative cell gives rise to a single, naked zoospore with heterokont flagella that settles and may become briefly amoeboid prior to dividing. Daughter cells are initially amoeboid, then either permanently attach and return to the benthic stage or become motile again prior to final settlement. Two deeply lobed chloroplasts occupy opposite ends of the cell and are surrounded by only two membranes. The outer chloroplast membrane is continuous between the two chloroplasts via the outer membrane of the nuclear envelope. Only two membranes occupy the chloroplast-nucleus interface, the inner membrane of the nuclear envelope and the inner chloroplast membrane. A small pyrenoid is found in each chloroplast and closely abuts the nucleus or protrudes into it. It contains an unusual, membrane-bound inclusion that stains with SYBR green but is unlikely to be a nucleomorph. Phylogenies inferred from a 10-gene concatenated alignment show an early-branching position within the PX clade. The unusual morphological features and phylogenetic position indicate C. australica should be classified as a new class, Chrysoparadoxophyceae. Despite an atypical plastid, exploration of the C. australica transcriptome revealed typical heterokont protein targeting to the plastid.