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 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.

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

Species limits in Pteruthius (Aves: Corvida) shrike-babblers: a comparison between the Biological and Phylogenetic Species Concepts

Zootaxa ◽  
2009 ◽  
Vol 2301 (1) ◽  
pp. 29-54 ◽  
Author(s):  
FRANK E. RHEINDT ◽  
JAMES A. EATON
Keyword(s):  
Species Concept ◽  
Molecular Data ◽  
Biological Species ◽  
Species Concepts ◽  
Biological Species Concept ◽  
Phylogenetic Species ◽  
Species Status ◽  
Phylogenetic Species Concept ◽  
Sampling Regime ◽  
Morphological And Molecular Data

The question of how to define a species continues to divide biologists. Meanwhile, the application of different species concepts has led to disparate taxonomic treatments that confound conservationists and other biologists. The most widely followed guidelines to species designation in avian and other vertebrate taxonomy are Ernst Mayr’s Biological Species Concept (BSC) and Joel Cracraft’s version of the Phylogenetic Species Concept (PSC). Although the BSC is considered to be more conservative in its assignment of species status, there is a lack of research demonstrating differences in taxonomic treatment between the BSC and the PSC with reference to a multi-taxon multi-trait study system. We examined the case of five traditionally recognized species of shrike-babbler (Pteruthius) that have recently been divided into 19 species under the PSC. Re-analyzing previous morphological and molecular data and adding new vocal data, we propose a BSC classification of 9 species. However, taking into consideration geographic gaps in the sampling regime, we contend that additional data will likely reduce discrepancies between the total numbers of species designated under the PSC and BSC. The current PSC species total is a likely overestimate owing to species diagnosis based on characters that erroneously appear to be unique to a taxon at low sample size. The current BSC species total as here proposed is a likely underestimate on account of the conservative designation of taxa as subspecies in equivocal cases, e.g. where BSC species status is potentially warranted but may be masked by insufficient data.

Species

2021 ◽  
pp. 219-238
Author(s):  
Andrew V. Z. Brower ◽  
Randall T. Schuh
Keyword(s):  
Species Concept ◽  
Biological Species ◽  
Species Concepts ◽  
Biological Species Concept ◽  
Character State ◽  
Phylogenetic Species Concept ◽  
Units Of Analysis ◽  
Perceived Reality

This chapter studies the systematists' perspective on species concepts and the role of species in systematics. No matter how sophisticated the tools and methods enhancing the conceptualization of reality may become in the future, systematists will still be constrained by their perceptions. In their more modest, empirical view, systematists embrace their perceived reality and prefer species concepts that incorporate tools for identifying and delimiting species as empirical hypotheses, thereby providing them with efficacious working terminal elements for phylogenetic analysis and classification of more inclusive taxa. It is fortunate that cladists employed the notion of a “phylogenetic” species concept based on diagnosability before more metaphysically inclined authors appropriated the term for concepts founded on monophyly or common ancestors. As noted, Willi Hennig's species concept was a version of the “biological” species concept, and it fell to his followers to develop a species concept that is well suited to cladistic principles. Among the earliest of the post-Hennigian empiricists was American Museum ichthyologist Donn Rosen. Rosen's concept, sometimes called the apomorphic concept because of its requirement that every recognized species must have its own derived character state, accomplished two key advances for systematics: it proposed a cladistic criterion for recognizing species, and it defined species as the minimal units of analysis, as far as taxonomy is concerned, thus setting a lower bound for systematic inquiry.

Is the taxonomy appropriate? Delineating species for conservation purposes

2017 ◽  
Author(s):  
Richard Frankham ◽  
Jonathan D. Ballou ◽  
Katherine Ralls ◽  
Mark D. B. Eldridge ◽  
Michele R. Dudash ◽  
...  
Keyword(s):  
Species Concept ◽  
Conservation Management ◽  
Biological Species ◽  
Species Concepts ◽  
Outbreeding Depression ◽  
Biological Species Concept ◽  
Genetic Rescue ◽  
Low Genetic Diversity ◽  
Inbred Populations ◽  
Species Definitions

The first step in conservation management is to delineate groups for separate versus combined management. However, there are many problems with species delineation, including diverse species definitions, lack of standardized protocols, and poor repeatability of delineations. Definitions that are too broad will lead to outbreeding depression if populations are crossed, while those that split excessively may preclude genetic rescue of small inbred populations with low genetic diversity. To minimize these problems, we recommend the use of species concepts based upon reproductive isolation (such as the biological species concept) and advise against the use of phylogenetic and general lineage species concepts. We provide guidelines as to when taxonomy requires revision and outline protocols for robust species delineations.

scholarly journals An alternative species taxonomy of the birds of Mexico

2004 ◽  
Vol 4 (2) ◽  
pp. 1-32 ◽  
Author(s):  
Adolfo G. Navarro-Sigüenza ◽  
A. Townsend Peterson
Keyword(s):  
Species Concept ◽  
Bird Species ◽  
Biological Species ◽  
Species Concepts ◽  
Biological Species Concept ◽  
Phylogenetic Species ◽  
Phylogenetic Species Concept ◽  
Alternative Species ◽  
Species Taxonomy

Extensive debate has surrounded the application of alternative species concepts in Ornithology. The biological species concept (BSC) and phylogenetic species concept (PSC) have typically been set in opposition, with extensive debate on the relative merits of each. An alternative is the evolutionary species concept (ESC), which offers a perspective similar to that of the PSC, yet with several significant differences. To date, no major avifauna has been examined and compared among taxonomic viewpoints. Herein, we develop an alternative phylogenetic/evolutionary species taxonomy to the current BSC treatment for the more than 1000 bird species of Mexico. A total of 135 biological species was divided to produce a total of 323 phylogenetic/evolutionary species, 122 of which represent “new” endemic forms in Mexico.

scholarly journals Philosophically speaking, how many species concepts are there?

Zootaxa ◽  
2011 ◽  
Vol 2765 (1) ◽  
pp. 58 ◽  
Author(s):  
JOHN S. WILKINS
Keyword(s):  
Gene Pool ◽  
Ecological Niche ◽  
Species Concepts ◽  
Modern Synthesis ◽  
Common Gene ◽  
Sexual Species ◽  
Physiological Evidence ◽  
Genetic Species

It’s an old question in biology: what is a species? Many different answers have been given over the years, and there are indefinitely many “definitions” in the literature. Adding to R. L. Mayden’s list of 22 definitions (Mayden, 1997) , I counted 26 in play since the Modern Synthesis (2009a), and a new one, which I call the “polyphasic” concept (basically a consilience of many lines of morphological, ecological, genetic, and physiological evidence), has been implicitly extended from bacterial and other microbial contexts to macrobial species, although the terminology has not yet been transplanted (Colwell, 1970; Vandamme et al., 1996). However, on another count there are seven “basic” species concepts: agamospecies (asexuals), biospecies (reproductively isolated sexual species), ecospecies (ecological niche occupiers), evolutionary species (evolving lineages), genetic species (common gene pool), morphospecies (species defined by their form, or phenotypes), and taxonomic species (whatever a taxonomist calls a species).

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
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