Population genetics and zoogeography of Australian freshwater golden perch, Macquaria ambigua (Richardson 1845) (Teleostei: Percichthyidae), and electrophoretic identification of a new species from the Lake Eyre basin

1992 ◽  
Vol 43 (6) ◽  
pp. 1585 ◽  
Author(s):  
MK Musyl ◽  
CP Keenan
Keyword(s):  
Drainage Basin ◽  
Gene Pools ◽  
Internal Drainage ◽  
Allopatric Species ◽  
Subspecies Level ◽  
Allelic Differences ◽  
Starch Gel ◽  
Average Gene ◽  
Australian Freshwater ◽  
Two Populations

Populations of golden perch (Macquaria ambigua) were sampled from both sides of the Great Dividing Range (GDR): from the Murray-Darling drainage basin (Murray R., L. Keepit and Condamine R.), the L. Eyre internal drainage basin (Barcoo R. and Diamantina R.), and the internal drainage basin of the Bulloo R.-all to the west of the GDR-and from the Fitzroy drainage basin (Dawson R. and Nogoa R.) east of the GDR. Starch-gel and polyacrylamide electrophoresis of 12 enzyme systems plus two general muscle proteins was used to estimate the genetic variation within and between populations. Of the 18 presumed genetic loci examined, nine were either polymorphic at the P0.99 criterion level or exhibited fixed allelic differences between some of the populations. Within the Murray-Darling drainage basin, there was little indication of heterogeneity. Contingency Χ2 analyses of allelic distributions among drainage basins indicated significant levels of heterogeneity at six variable loci. The isolated L. Eyre population exhibited diagnostic alleles at four loci when compared with the Murray- Darling and Fitzroy populations. The genetic distance of the L. Eyre population (Nei's D=0.23) from these two populations indicates that the L. Eyre golden perch is most probably a previously unrecognized allopatric species. The level of divergence (0 = 0.06) between Fitzroy and Murray-Darling golden perch indicates differentiation at the subspecies level, with no fixed differences observed between these two populations. Finally, golden perch from the Bulloo R. represent either (i) an intermediate evolutionary unit between the presumed ancestral L. Eyre population and the derived Murray-Darling and Fitzroy populations or (ii) a complex hybrid between these populations. Average gene-flow statistics, FST = 0.760 and Nem=0.08, suggest that the populations in each of the four basins can be regarded as separate gene pools that have been isolated for different, and considerable, periods of time.

scholarly journals A Vibrio cholerae Core Genome Multilocus Sequence Typing Scheme To Facilitate the Epidemiological Study of Cholera

2020 ◽  
Vol 202 (24) ◽  
Author(s):  
Kevin Y. H. Liang ◽  
Fabini D. Orata ◽  
Mohammad Tarequl Islam ◽  
Tania Nasreen ◽  
Munirul Alam ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Multilocus Sequence Typing ◽  
Core Genome ◽  
Geographic Origin ◽  
Data Set ◽  
Epidemiological Research ◽  
Content Type ◽  
Typing Scheme ◽  
Subspecies Level ◽  
Allelic Differences

ABSTRACT Core genome multilocus sequence typing (cgMLST) has gained popularity in recent years in epidemiological research and subspecies-level classification. cgMLST retains the intuitive nature of traditional MLST but offers much greater resolution by utilizing significantly larger portions of the genome. Here, we introduce a cgMLST scheme for Vibrio cholerae, a bacterium abundant in marine and freshwater environments and the etiologic agent of cholera. A set of 2,443 core genes ubiquitous in V. cholerae were used to analyze a comprehensive data set of 1,262 clinical and environmental strains collected from 52 countries, including 65 newly sequenced genomes in this study. We established a sublineage threshold based on 133 allelic differences that creates clusters nearly identical to traditional MLST types, providing backwards compatibility to new cgMLST classifications. We also defined an outbreak threshold based on seven allelic differences that is capable of identifying strains from the same outbreak and closely related isolates that could give clues on outbreak origin. Using cgMLST, we confirmed the South Asian origin of modern epidemics and identified clustering affinity among sublineages of environmental isolates from the same geographic origin. Advantages of this method are highlighted by direct comparison with existing classification methods, such as MLST and single-nucleotide polymorphism-based methods. cgMLST outperforms all existing methods in terms of resolution, standardization, and ease of use. We anticipate this scheme will serve as a basis for a universally applicable and standardized classification system for V. cholerae research and epidemiological surveillance in the future. This cgMLST scheme is publicly available on PubMLST (https://pubmlst.org/vcholerae/). IMPORTANCE Toxigenic Vibrio cholerae isolates of the O1 and O139 serogroups are the causative agents of cholera, an acute diarrheal disease that plagued the world for centuries, if not millennia. Here, we introduce a core genome multilocus sequence typing scheme for V. cholerae. Using this scheme, we have standardized the definition for subspecies-level classification, facilitating global collaboration in the surveillance of V. cholerae. In addition, this typing scheme allows for quick identification of outbreak-related isolates that can guide subsequent analyses, serving as an important first step in epidemiological research. This scheme is also easily scalable to analyze thousands of isolates at various levels of resolution, making it an invaluable tool for large-scale ecological and evolutionary analyses.

Isozyme variation in eastern hemlock

1992 ◽  
Vol 22 (12) ◽  
pp. 1838-1842 ◽  
Author(s):  
Catherine Zabinski
Keyword(s):  
Genetic Variation ◽  
Polymorphic Locus ◽  
Continuous Distribution ◽  
Eastern Hemlock ◽  
Unexpected Result ◽  
Starch Gel Electrophoresis ◽  
Coniferous Species ◽  
Disjunct Populations ◽  
Starch Gel ◽  
Two Populations

Tsugacanadensis (L.) Carr., commonly known as eastern hemlock, is a coniferous tree native to eastern North America. The western and southern edges of its geographic distribution are characterized by disjunct populations 50–100 km or more from the continuous distribution. Genetic variation was measured using starch gel electrophoresis of needle tissue enzymes from 17 populations throughout the species' distribution. Six enzyme systems including 10 putative loci were assayed, with only 1 of the 10 loci being polymorphic. The polymorphic locus, cytochrome oxidase, consisted of two alleles present in all but two populations. Allele frequencies averaged 0.69 and 0.31. The low level of genetic variation in eastern hemlock was an unexpected result, given that most coniferous species are highly variable.

Genetic diversity between Italian and Greek buffalo populations

2001 ◽  
Vol 29 ◽  
pp. 31-40 ◽  
Author(s):  
B. Moioli ◽  
A. Georgoudis ◽  
F. Napolitano ◽  
G. Catillo ◽  
S. Lucioli ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Gene Diversity ◽  
Genetic Distances ◽  
Allele Frequency Distribution ◽  
Average Gene Diversity ◽  
Polymorphic Microsatellite ◽  
Average Gene ◽  
Degree Of Differentiation ◽  
Two Populations ◽  
Global Project

SummaryThe present study is a first step of a global project aiming at the estimation of the genetic distances and relationships among buffalo breeds and sub-populations and the investigation of the production potential and adaptability of different buffalo genotypes in various environments.Genetic diversity of Italian and Greek buffalo populations was estimated on the basis of allele frequencies at nine polymorphic microsatellite loci: CSSM43, CSSM38, DRB3, D21S4, CYP21, CSSM47, CSSM60, CSSM36 and CSSM33. The number of detected alleles per locus varied from two (D21S4) to thirteen (CSSM47). Allele frequency distribution was similar in the two populations, which have the same alleles at the highest frequency at all loci, except loci CSSM47 and CSSM60. Average gene diversity over all loci was 0.60. Across-loci average gene diversity increased with the number of alleles. Observed average heterozygosity was 0.167 and 0.177 in the Italian and Greek populations, respectively. The degree of differentiation between Italian and Greek buffalo was moderate and estimated at 0.021 ± 0.009.

Genetic Uniformity in an Introduced Population of Witchweed (Striga asiatica) in the United States

Weed Science ◽  
1984 ◽  
Vol 32 (5) ◽  
pp. 645-648 ◽  
Author(s):  
Charles R. Werth ◽  
James L. Riopel ◽  
Nan W. Gillespie
Keyword(s):  
South Carolina ◽  
The United States ◽  
Starch Gel Electrophoresis ◽  
Parasitic Weed ◽  
Limited Region ◽  
Striga Asiatica ◽  
Genetic Uniformity ◽  
Starch Gel ◽  
North And South ◽  
Two Populations

Witchweed, [Striga asiatica(L.) Kuntze5STRLU], an important parasitic weed throughout much of the old world, occurs as a recent (30 yr) introduction in a limited region in North and South Carolina. Reproduction in this population has been shown to occur primarily through self-pollination of flowers. Genetic diversity in two populations from this region was assessed, utilizing starch gel electrophoresis and staining of enzymes. An average of 64 individuals was observed to be monomorphic at an estimated minimum of 32 genetic loci coding 18 enzyme systems. This lack of polymorphism is attributable to the probable founding of the population by one or a few individuals coupled with the predominantly autogamous breeding system.

scholarly journals Genetic variation of Abies alba Mill. in Polish part of Sudety Mts.

2014 ◽  
Vol 70 (3) ◽  
pp. 215-219 ◽  
Author(s):  
Andrzej Lewandowski ◽  
Maciej Filipiak ◽  
Jarosław Burczyk
Keyword(s):  
Gel Electrophoresis ◽  
Abies Alba ◽  
Silver Fir ◽  
Allozyme Polymorphism ◽  
Starch Gel Electrophoresis ◽  
Expected Heterozygosity ◽  
Starch Gel ◽  
The Mean ◽  
Allozyme Loci ◽  
Two Populations

The genetic structure of silver fir (<em>Abies alba</em> Mill.) was investigated among 8 populations from Sudety Mts. and 2 additional populations from other parts of Poland. Nine enzyme systems controlled by 13 allozyme loci were analyzed using starch gel electrophoresis. The mean expected heterozygosity, ranging from 0.06 to 0.11 and was lower compared to that found in other conifers. The mean genetic distance among all silver fir populations was 0.005. The Sudeten group of populations appeared to be genetically different from the two populations from other parts of Poland, indicating that at least two different centers are responsible for the current distribution of allozyme polymorphism in the tested populations.

Regional features of desertification processes of ecosystems on the border of the Baikal basin and Central Asian internal drainage basin

2015 ◽  
Vol 5 (3) ◽  
pp. 117-133 ◽  
Author(s):  
P. D. Gunin ◽  
S. N. Bazha ◽  
E. V. Danzhalova ◽  
Yu. I. Drobyshev ◽  
L. A. Ivanov ◽  
...  
Keyword(s):  
Drainage Basin ◽  
Internal Drainage ◽  
Baikal Basin ◽  
Regional Features ◽  
Central Asian

Gentic Differentiation, Hybridization and Reproductive Isolation in Mygalopsis marki Bailey (Orthoptera: Tettigoniidae)

1983 ◽  
Vol 31 (3) ◽  
pp. 353 ◽  
Author(s):  
IR Dadour ◽  
MS Johnson
Keyword(s):  
Linkage Disequilibrium ◽  
Hybrid Zone ◽  
Sibling Species ◽  
Random Mating ◽  
Gene Pools ◽  
Strong Linkage Disequilibrium ◽  
Strong Linkage ◽  
Number Of Teeth ◽  
The Mean ◽  
Two Populations

Differentiation between northern and southern populations of M. marki was revealed for the sex- linked enzyme PGM, the autosomal enzyme LGGP, and the number of teeth on the stridulatory file. Northern populations are fixed for the PGMb allele, and possess the LGGPd allele at moderate frequencies, whereas southern populations are fixed for PGMa and lack LGGPd. Northern populations also have lower mean numbers of teeth. A zone of overlap was indicated by two populations polymorphic for PGM. Within these populations, genotypic frequencies for both PGM (in females) and LGGP conform closely with Hardy-Weinberg expectations, implying random mating. Despite this, the unlinked PGM and LGGP are in strong linkage disequilibrium, with LGGPd found only with PGMb. Furthermore, the mean number of teeth is lower in PGMb than in PGMa males in the polymorphic populations. This association of genetically and functionally independent traits indicates that northern and southern gene pools are isolated, and that the area of overlap is a hybrid zone between two sibling species.

Enumeration and Identification of Asbestos Fibres in Water

1974 ◽  
Vol 32 ◽  
pp. 526-527 ◽  
Author(s):  
O. Mudroch ◽  
J. R. Kramer
Keyword(s):  
Water Supply ◽  
Water Samples ◽  
Drainage Basin ◽  
Lake Superior ◽  
Research Work ◽  
List Type ◽  
The West ◽  
Asbestos Fibre ◽  
Amphibole Asbestos

Approximately 60,000 tons per day of waste from taconite mining, tailing, are added to the west arm of Lake Superior at Silver Bay. Tailings contain nearly the same amount of quartz and amphibole asbestos, cummingtonite and actinolite in fibrous form. Cummingtonite fibres from 0.01μm in length have been found in the water supply for Minnesota municipalities.The purpose of the research work was to develop a method for asbestos fibre counts and identification in water and apply it for the enumeration of fibres in water samples collected(a) at various stations in Lake Superior at two depth: lm and at the bottom.(b) from various rivers in Lake Superior Drainage Basin.

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