scholarly journals Standardized nuclear markers advance metazoan taxonomy

2021 ◽  
Author(s):  
Lars Dietz ◽  
Jonas Eberle ◽  
Christoph Mayer ◽  
Sandra Kukowka ◽  
Claudia Bohacz ◽  
...  

Species are the fundamental units of life and their recognition is essential for science and society. DNA barcoding, the use of a single and often mitochondrial gene, has been increasingly employed as a universal approach for the identification of animal species. However, this approach faces several challenges. Here, we demonstrate with empirical data from a number of metazoan animal lineages that multiple nuclear-encoded markers, so called universal single-copy orthologs (USCOs) performs much better than the single barcode gene to discriminate closely related species. Overcoming the general shortcomings of mitochondrial DNA barcodes, USCOs also accurately assign samples to higher taxonomic levels. These loci thus provide a powerful and unifying framework for species delimitation which considerably improves the DNA-based inference of animal species.

Genetics ◽  
1998 ◽  
Vol 150 (4) ◽  
pp. 1605-1614
Author(s):  
Junyuan Wu ◽  
Konstantin V Krutovskii ◽  
Steven H Strauss

Abstract We examined mitochondrial DNA polymorphisms via the analysis of restriction fragment length polymorphisms in three closely related species of pines from western North America: knobcone (Pinus attenuata Lemm.), Monterey (P. radiata D. Don), and bishop (P. muricata D. Don). A total of 343 trees derived from 13 populations were analyzed using 13 homologous mitochondrial gene probes amplified from three species by polymerase chain reaction. Twenty-eight distinct mitochondrial DNA haplotypes were detected and no common haplotypes were found among the species. All three species showed limited variability within populations, but strong differentiation among populations. Based on haplotype frequencies, genetic diversity within populations (HS) averaged 0.22, and population differentiation (GST and θ) exceeded 0.78. Analysis of molecular variance also revealed that >90% of the variation resided among populations. For the purposes of genetic conservation and breeding programs, species and populations could be readily distinguished by unique haplotypes, often using the combination of only a few probes. Neighbor-joining phenograms, however, strongly disagreed with those based on allozymes, chloroplast DNA, and morphological traits. Thus, despite its diagnostic haplotypes, the genome appears to evolve via the rearrangement of multiple, convergent subgenomic domains.


Zootaxa ◽  
2018 ◽  
Vol 4403 (2) ◽  
pp. 378 ◽  
Author(s):  
EUGENYI A. MAKARCHENKO ◽  
MARINA A. MAKARCHENKO ◽  
ALEXANDER A. SEMENCHENKO ◽  
DMITRY M. PALATOV

Illustrated descriptions of the adult male, pupa and fourth instar larva, as well as DNA barcoding results of Chaetocladius (Chaetocladius) elisabethae sp. nov. in comparison with closely related species of Chaetocladius s. str. from the Moscow Region are provided. A reference 658 bp barcode sequence from a fragment of the mitochondrial gene cytochrome oxidase I (COI) was used as a tool for species delimitation. Comparisons with corresponding regions of COI between C. (s. str.) elisabethae sp. nov. and other species of the subgenus produced K2P genetic distances of 0.11–0.16, values well associated with interspecific variation. The barcodes of the new species were identical to the Chaetocladius sp. 2ES in BOLD systems. Molecular data were also used for the reconstruction of the phylogenetic relationships within the subgenus Chaetocladius s. str. 


Zootaxa ◽  
2017 ◽  
Vol 4362 (3) ◽  
pp. 359 ◽  
Author(s):  
ANDRE WAGNER ◽  
LAURENT VUATAZ ◽  
MICHEL SARTORI

A new species belonging to the speciose genus Electrogena Zurwerra & Tomka, 1985 is described based on all stages from material collected in Switzerland, northern Italy and Slovenia. Electrogena brulini Wagner sp. nov. is closely related to E. gridellii (Grandi, 1953). A genetic analysis based on the mitochondrial gene CO1, including 9 specimens from 5 populations, reveals a K2P distance of 22% between both species. Our investigations demonstrate that the description of the nymph of E. gridellii sensu Belfiore (1996) refers in fact to both species. Therefore, E. gridellii is redescribed in all stages. The number of bristles on each mandibular prostheca in the nymphs, the shape of titillators in male genitalia and the shape of the subanal plate in female imagines are the main characters allowing discrimination of these two species. This study also shows that in this case it is possible and helpful to use colour patterns to separate two closely related species. The re-examination of the type material of Electrogena vipavensis Zurwerra & Tomka, 1986 described from western Slovenia indicates that this species is a junior subjective synonym of E. gridellii. 


2007 ◽  
Vol 274 (1619) ◽  
pp. 1731-1739 ◽  
Author(s):  
T.L Whitworth ◽  
R.D Dawson ◽  
H Magalon ◽  
E Baudry

In DNA barcoding, a short standardized DNA sequence is used to assign unknown individuals to species and aid in the discovery of new species. A fragment of the mitochondrial gene cytochrome c oxidase subunit 1 is emerging as the standard barcode region for animals. However, patterns of mitochondrial variability can be confounded by the spread of maternally transmitted bacteria that cosegregate with mitochondria. Here, we investigated the performance of barcoding in a sample comprising 12 species of the blow fly genus Protocalliphora , known to be infected with the endosymbiotic bacteria Wolbachia . We found that the barcoding approach showed very limited success: assignment of unknown individuals to species is impossible for 60% of the species, while using the technique to identify new species would underestimate the species number in the genus by 75%. This very low success of the barcoding approach is due to the non-monophyly of many of the species at the mitochondrial level. We even observed individuals from four different species with identical barcodes, which is, to our knowledge, the most extensive case of mtDNA haplotype sharing yet described. The pattern of Wolbachia infection strongly suggests that the lack of within-species monophyly results from introgressive hybridization associated with Wolbachia infection. Given that Wolbachia is known to infect between 15 and 75% of insect species, we conclude that identification at the species level based on mitochondrial sequence might not be possible for many insects. However, given that Wolbachia -associated mtDNA introgression is probably limited to very closely related species, identification at the genus level should remain possible.


Genes ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 38 ◽  
Author(s):  
Dehuai Luo ◽  
Yanping Li ◽  
Qingyuan Zhao ◽  
Lianpeng Zhao ◽  
Arne Ludwig ◽  
...  

Order Acipenseriformes contains 27 extant species distributed across the northern hemisphere, including so-called “living fossil” species of garfish and sturgeons. Previous studies have focused on their mitochondrial genetics and have rarely used nuclear genetic data, leaving questions as to their phylogenetic relationships. This study aimed to utilize a bioinformatics approach to screen for candidate single-copy nuclear genes, using transcriptomic data from sturgeon species and genomic data from the spotted gar, Lepisosteus oculatus. We utilized nested polymerase chain reaction (PCR) and degenerate primers to identify nuclear protein-coding (NPC) gene markers to determine phylogenetic relationships among the Acipenseriformes. We identified 193 nuclear single-copy genes, selected from 1850 candidate genes with at least one exon larger than 700 bp. Forty-three of these genes were used for primer design and development of 30 NPC markers, which were sequenced for at least 14 Acipenseriformes species. Twenty-seven NPC markers were found completely in 16 species. Gene trees according to Bayesian inference (BI) and maximum likelihood (ML) were calculated based on the 30 NPC markers (20,946 bp total). Both gene and species trees produced very similar topologies. A molecular clock model estimated the divergence time between sturgeon and paddlefish at 204.1 Mya, approximately 10% later than previous estimates based on cytochrome b data (184.4 Mya). The successful development and application of NPC markers provides a new perspective and insight for the phylogenetic relationships of Acipenseriformes. Furthermore, the newly developed nuclear markers may be useful in further studies on the conservation, evolution, and genomic biology of this group.


Zootaxa ◽  
2008 ◽  
Vol 1691 (1) ◽  
pp. 67 ◽  
Author(s):  
M. ALEX SMITH

The 5' end (Folmer or Barcode region) of cytochrome c oxidase 1 (CO1) has been proposed as the gene region of choice for a standardized animal DNA barcode (Hebert et al. 2003). Concerns have been raised regarding the decision to utilize this particular mitochondrial gene region as a barcode. Nevertheless, widely divergent taxonomic groups have reported success using CO1 for both species identification and discovery. The utility of CO1 for barcoding amphibians was raised early on (Vences, et al. 2005) and concerns for this group were reported widely (Waugh 2007)—although some considered that the reporting of the concerns outstripped the data that had been analyzed at that point (Smith et al. 2008). Indeed, our analysis of CO1 for a small group of Holarctic amphibians was neither more difficult to generate nor to analyze than for other groups where we have utilized the technique.


PLoS ONE ◽  
2013 ◽  
Vol 8 (10) ◽  
pp. e76957 ◽  
Author(s):  
Carl J. Rothfels ◽  
Anders Larsson ◽  
Fay-Wei Li ◽  
Erin M. Sigel ◽  
Layne Huiet ◽  
...  
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2006 ◽  
Vol 36 (2) ◽  
pp. 337-350 ◽  
Author(s):  
Shelley L Ball ◽  
Karen F Armstrong

Reliable and rapid identification of exotic pest species is critical to biosecurity. However, identification of morphologically indistinct specimens, such as immature life stages, that are frequently intercepted at borders is often impossible. Several DNA-based methods have been used for species identification; however, a more universal and anticipatory identification system is needed. Consequently, we tested the ability of DNA "barcodes" to identify species of tussock moths (Lymantriidae), a family containing several important pest species. We sequenced a 617 base pair fragment of the mitochondrial gene cytochrome c oxidase 1 for 20 lymantriid species. We used these, together with other Noctuoidea species sequences from GenBank and the Barcoding of Life Database to create a "profile" or reference sequence data set. We then tested the ability of this profile to provide correct species identifications for 93 additional lymantriid specimens from a data set of mock unknowns. Of the unknowns, 100% were correctly identified by the cytochrome c oxidase 1 profile. Mean interspecific sequence (Kimura 2-parameter) divergence was an order of magnitude greater (14%) than mean intraspecific divergence (<1%). Four species showed deeper genetic divergences among populations. We conclude that DNA barcodes provide a highly accurate means of identifying lymantriid species and show considerable promise as a universal approach to DNA-based identification of pest insects.


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