Why We Need a New Genetic Species Concept

1989 ◽  
Vol 38 (3) ◽  
pp. 270 ◽  
Author(s):  
J. C. Masters ◽  
H. G. Spencer
Keyword(s):  
Species Concept ◽  
Genetic Species Concept ◽  
Genetic Species

scholarly journals “Genetic Species” Concept in Xanthomonas

1965 ◽  
Vol 89 (1) ◽  
pp. 95-100
Author(s):  
S. Friedman ◽  
J. De Ley
Keyword(s):  
Species Concept ◽  
Genetic Species Concept ◽  
Genetic Species

scholarly journals Evolutionary Genetic Species Detected in Prokaryotes by Applying the K/θ Ratio to DNA Sequences

2020 ◽  
Author(s):  
C. William Birky
Keyword(s):  
Dna Sequences ◽  
Core Genome ◽  
Species Concept ◽  
Single Gene ◽  
Species Boundaries ◽  
Genetic Theory ◽  
Evolutionary Genetic ◽  
Genetic Species Concept ◽  
Genetic Species ◽  
General Method

AbstractIn previous papers in this series, I described the “evolutionary genetic species concept” which is based on population genetic theory and should be applicable to any organism. I also described a species criterion, the K/θ ratio, that delimits independently evolving evolutionary species based on single-gene sequences. I then illustrated its application to sexual and asexual eukaryotes. Here, I show how the evolutionary genetic species concept and the K/θ ratio can be applied to bacteria, using the sequences from some genes of the core genome that are rarely, if ever, transferred horizontally between different species. This completes the demonstration that K/θ is a general method for species delimitation, applicable to all organisms. Also, it adds to the evidence that bacteria have species in the most general sense, even though they have the ability to exchange genes across species boundaries. Finally, I show that a published critique of the use of K/θ ≥ 4 as a criterion for independently evolving species rests on two errors in the application of population/evolutionary genetic theory.

The genetic species concept and its versatility

2021 ◽  
pp. 60-68
Author(s):  
Sergey Mezhzherin
Keyword(s):  
Gene Pool ◽  
Species Concept ◽  
Biological Species ◽  
Species Concepts ◽  
Structural Genes ◽  
Evolutionary Genetic ◽  
Genetic Species Concept ◽  
Genetic Species

A review of the species criteria of the four most popular species concepts (typological, genetic, bio-logical, and evolutionary-phylogenetic) shows that they are essentially the same. In each of them, the fact of fixing alternative alleles in diverging populations is a key circumstance in one form or another. Such groups of populations should be considered as a kind of evolutionary genetic dis-creteness supported by a protected gene pool. Therefore, a biological species should be understood as a set of populations, individuals of which have the fixation of common unique alleles for a num-ber of structural genes. Differences between the concepts are secondary and are due to the emphasis on different sides of the same phenomenon or the use of different methods for determining the ge-netic structure. It is indicated that there are subjective difficulties in the application of the genetic concept (the reluctance of traditional taxonomists to lose their monopoly) and objective problems caused by the unequal period of divergence of taxa of the species rank and different ways of form-ing genetically discrete entities.

scholarly journals SPECIATION IN MAMMALS AND THE GENETIC SPECIES CONCEPT

2006 ◽  
Vol 87 (4) ◽  
pp. 643-662 ◽  
Author(s):  
Robert J. Baker ◽  
Robert D. Bradley
Keyword(s):  
Species Concept ◽  
Genetic Species Concept ◽  
Genetic Species

scholarly journals On the Bennelongia barangaroo lineage (Crustacea, Ostracoda) in Western Australia, with the description of seven new species

2013 ◽  
Author(s):  
Koen Martens ◽  
Stuart Halse ◽  
Isa Schön
Keyword(s):  
New Species ◽  
Western Australia ◽  
Molecular Evidence ◽  
Nominal Species ◽  
Rock Pools ◽  
Additional Species ◽  
Coi Sequences ◽  
The Right ◽  
Genetic Species Concept ◽  
Genetic Species

The ostracod genus Bennelongia De Deckker & McKenzie, 1981 is endemic to Australia and New Zealand. Extensive sampling in Western Australia (WA) revealed a high specific and largely undescribed diversity. Here, we describe seven new species belonging to the B. barangaroo lineage: B. timmsi sp. nov., B. gnamma sp. nov., B. hirsuta sp. nov., B. ivanae sp. nov., B. mcraeae sp. nov., B. scanloni sp. nov. and B. calei sp. nov., and confirm the presence of an additional species, B. dedeckkeri, in WA. For five of these eight species, we could construct molecular phylogenies and parsimonious networks based on COI sequences. We also tested for cryptic diversity and specific status of clusters with a statistical method based on the evolutionary genetic species concept, namely Birky’s 4 theta rule. The analyses support the existence of these five species and a further three cryptic species in the WA B. barangaroo lineage. The molecular evidence was particularly relevant because most species described herein have very similar morphologies and can be distinguished from each other only by the shape, size and position of the antero-ventral lapel on the right valve, and, in sexual populations, by the small differences in shape of the hemipenes and the prehensile palps in males. Four species of the WA B. barangaroo lineage occur in small temporary rock pools (gnammas) on rocky outcrops. The other four species are mainly found in soft bottomed seasonal water bodies. One of the latter species, B. scanloni sp. nov., occurs in both claypans and deeper rock pools (pit gnammas). All species, except for B. dedeckkeri, originally described from Queensland, have quite clearly delimited distributions in WA. With the seven new species described here, the genus Bennelongia now comprises 25 nominal species but several more await formal description.

Systematics and evolution of Nepenthes

2018 ◽  
Author(s):  
Charles Clarke ◽  
Jan Schlauer ◽  
Jonathan Moran ◽  
Alastair Robinson
Keyword(s):  
Southeast Asia ◽  
Analytical Methods ◽  
Best Practice ◽  
Species Concept ◽  
Reticulate Evolution ◽  
Ecological Information ◽  
Plastid Genomes ◽  
The Status ◽  
Species Descriptions ◽  
Adequate Research

Nepenthes is a genus of 130-160 species, almost half of which were described after 2001. The recent, rapid increase in species descriptions has been driven by application of a less rigorous species concept by botanists, taxonomic inflation, and discoveries of new taxa during explorations of remote parts of Southeast Asia. Many recently published species descriptions of Nepenthes are based entirely upon qualitative morphological information and are not supported by adequate research. Accordingly, the status of many Nepenthes taxa is contested. Evolution within the genus is not well understood, because nuclear and maternally inherited plastid genomes cannot resolve relationships between many species, particularly those that evolved recently through introgression or reticulate evolution. Improvement in our understanding of the systematics and evolution of Nepenthes requires the adoption of ‘best practice’ collection and preservation methods, and the application of quantitative analytical methods for morphological, genetic, and ecological information.

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