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- Zamora, Juan Carlos, et al.
(författare)
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Considerations and consequences of allowing DNA sequence data as types of fungal taxa
- 2018
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Ingår i: IMA Fungus. - : INT MYCOLOGICAL ASSOC. - 2210-6340 .- 2210-6359. ; 9:1, s. 167-185
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Tidskriftsartikel (refereegranskat)abstract
- Nomenclatural type definitions are one of the most important concepts in biological nomenclature. Being physical objects that can be re-studied by other researchers, types permanently link taxonomy (an artificial agreement to classify biological diversity) with nomenclature (an artificial agreement to name biological diversity). Two proposals to amend the International Code of Nomenclature for algae, fungi, and plants (ICN), allowing DNA sequences alone (of any region and extent) to serve as types of taxon names for voucherless fungi (mainly putative taxa from environmental DNA sequences), have been submitted to be voted on at the 11th International Mycological Congress (Puerto Rico, July 2018). We consider various genetic processes affecting the distribution of alleles among taxa and find that alleles may not consistently and uniquely represent the species within which they are contained. Should the proposals be accepted, the meaning of nomenclatural types would change in a fundamental way from physical objects as sources of data to the data themselves. Such changes are conducive to irreproducible science, the potential typification on artefactual data, and massive creation of names with low information content, ultimately causing nomenclatural instability and unnecessary work for future researchers that would stall future explorations of fungal diversity. We conclude that the acceptance of DNA sequences alone as types of names of taxa, under the terms used in the current proposals, is unnecessary and would not solve the problem of naming putative taxa known only from DNA sequences in a scientifically defensible way. As an alternative, we highlight the use of formulas for naming putative taxa (candidate taxa) that do not require any modification of the ICN.
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| 2. |
- Sundberg, Henrik
(författare)
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Contributions to the understanding of diversity and evolution in the genus Coreomyces
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The Laboulbeniales is an order of enigmatic ascomycete fungi that are obligate microscopic parasites of arthropods, which are usually non-detrimental. They typically display a high degree of host specificity, and the genus Coreomyces, which is the recurring theme of this thesis, is no exception. Coreomyces is a small aquatic genus parasitising water boatmen (Corixidae). Members in this genus present something that is unique for Laboulbeniales, position specificity. This means that a parasite is restricted to a specific position on the host. This thesis aims at elucidating the patterns of host and position specificity present in the genus Coreomyces by the use of molecular markers. A second aim is to describe new taxa encountered during the course of the project. Finally we wanted to reveal what mating system is present in a member of the Laboulbeniales, something that has never been done before. Understanding the mode of sexual reproduction and to get insights into mating type organisation can give important clues to how the species patterns we observe may have evolved. To achieve these goals we first had to develop a robust and simple molecular methodology that made use of as little material as possible, preferably a single thallus. Our results showed that position specificity indeed exists in this genus, but that it is not as strict as previously presumed, all species we analysed occupied more than one position. Further we were able to show that thalli found in the same position on different hosts constitute the same species, and also that two sister species utilise the same position. We conclude that, in most cases, growth position is more important than host species or host sex in species delimitation. We confirmed the presence of four discrete taxa, two of which were described as new species, Coreomyces confusus H. Sundb. et al. and C. dextrorsus H. Sundb. et al. Finally we were able to show that C. macropus and C. confusus are likely to display a homothallic breeding system.
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