The systematic status of the lagoon periwinkle, Littorina tenebrosa

1999 ◽  
Vol 79 (4) ◽  
pp. 653-660 ◽  
Author(s):  
Iain F. Wilson ◽  
Elizabeth M. Gosling ◽  
William Tapper
Keyword(s):  
Phylogenetic Analysis ◽  
Genetic Variation ◽  
Gene Flow ◽  
Genetic Distance ◽  
Gel Electrophoresis ◽  
Distinct Group ◽  
Starch Gel Electrophoresis ◽  
Allopatric Populations ◽  
Starch Gel ◽  
The Mean

Eight samples of Littorina tenebrosa and L. saxatilis (Mollusca: Gastropoda) from Ireland and Britain, including pairs of each form from two locations in Ireland, were screened for genetic variation at 12 polymorphic enzyme loci using starch gel electrophoresis. Levels of polymorphism and heterozygosity were similar in L. tenebrosa and L. saxatilis, apart from a sample of L. tenebrosa from Britain which was less polymorphic than the Irish samples. No alleles were found to be unique to either form. Phylogenetic analysis using UPGMA showed that L. saxatilis and L. tenebrosa populations clustered as a monophyletic group. Nevertheless, the mean genetic distance between parapatric populations of L. saxatilis and L. tenebrosa (D=0.076) was similar to the mean for allopatric populations of either species (D=0.080). This indicates that there is a barrier to gene flow between the two forms Despite this, L. tenebrosa does not merit specific status since populations of this snail do not cluster as a distinct group, separate from L. saxatilis populations.

Allozyme differentiation among gopher tortoises (Gopherus): conservation genetics and phylogenetic and taxonomic implications

1994 ◽  
Vol 72 (9) ◽  
pp. 1665-1671 ◽  
Author(s):  
David J. Morafka ◽  
Gustavo Aguirre L. ◽  
Robert W. Murphy
Keyword(s):  
Genetic Distance ◽  
Gel Electrophoresis ◽  
Genetic Similarity ◽  
Species Variation ◽  
Starch Gel Electrophoresis ◽  
Direct Count ◽  
Allopatric Populations ◽  
Starch Gel ◽  
Taxonomic Implications ◽  
Weinberg Expectation

The genetic diversity among 18 loci within and among four species of gopher tortoises was investigated using horizontal starch gel electrophoresis. Within species variation ranged from 2 to 4% by direct count and from 2 to 8% by Hardy–Weinberg expectation. Of the loci resolved, 11–22% expressed variation. The northern and southern populations of Gopherus flavomarginatus could not be distinguished. No fixed differences were observed between G. agassizii and G. berlandieri, as reflected in a Nei genetic distance of 0.008. These latter species may be little more than allopatric populations of G. agassizii. Differentiation between the two remaining species was not extensive; G. polyphemus was only slightly distinct from G. flavomarginatus, being separated by a Nei genetic distance of only 0.006. The two pairs of species were separated by an average genetic distance of 0.200. The evolutionary rates of divergence were observed to be unequal, especially between G. polyphemus and G. flavomarginatus. The overall genetic similarity suggests a relatively recent age of origin.

Survey of the Genetic Variation Among Eastern Lake Superior Lake Trout (Salvelinus namaycush)

1981 ◽  
Vol 38 (12) ◽  
pp. 1738-1746 ◽  
Author(s):  
Terrence R. Dehring ◽  
Anne F. Brown ◽  
Charles H. Daugherty ◽  
Stevan R. Phelps
Keyword(s):  
Genetic Variation ◽  
Gel Electrophoresis ◽  
Lake Trout ◽  
Lake Superior ◽  
Salvelinus Namaycush ◽  
Starch Gel Electrophoresis ◽  
Average Heterozygosity ◽  
Management Implications ◽  
Salmonid Species ◽  
Starch Gel

Patterns of genetic variation among lake trout (Salvelinus namaycush) of eastern Lake Superior were examined using starch gel electrophoresis. We used 484 individuals sampled from three areas, representing three morphological types (leans, humpers, and siscowets). Of 50 loci examined, 44 were monomorphic in all groups sampled. Genetic variation occurs at six loci AAT-1,2, MDH-3,4, ME-1, and SOD-1. The average heterozygosity found (H = 0.015) is low relative to other salmonid species. A significant amount of heterogeneity exists among the 10 lake trout samples. These differences are due to variation within as well as between morphological types. The significance and management implications of these data are discussed.Key words: genetic variation, lake trout, Salvelinus namaycush, Lake Superior

Genetic variation in pika populations

1977 ◽  
Vol 55 (11) ◽  
pp. 1841-1845 ◽  
Author(s):  
D. G. Glover ◽  
M. H. Smith ◽  
L. Ames ◽  
J. Joule ◽  
J. M. Dubach
Keyword(s):  
Genetic Variation ◽  
Gel Electrophoresis ◽  
Starch Gel Electrophoresis ◽  
Genetic Loci ◽  
Starch Gel

Analysis of 26 genetic loci by horizontal starch gel electrophoresis was performed on 197 pikas from one Montana and four Colorado populations. Only four loci were polymorphic within populations and individual heterozygosity was low for a mammal [Formula: see text]. The Montana and Colorado populations were fixed for alternate allelles at three loci. Because of the insular nature of pika habitat, drift is probably important in determining low heterozygosities and genetic similarities measured between widely separated pika populations.

Little genetic variation in the oil sardine, Sardinella longiceps Val., from the western coast of India

1994 ◽  
Vol 45 (2) ◽  
pp. 257 ◽  
Author(s):  
MR Menezes
Keyword(s):  
Genetic Variation ◽  
Gel Electrophoresis ◽  
Western Coast ◽  
Starch Gel Electrophoresis ◽  
Marine Fish Species ◽  
Average Heterozygosity ◽  
Enzyme Gene ◽  
Starch Gel ◽  
Sardinella Longiceps ◽  
Gene Variability

Enzyme gene variability in the oil sardine, Sardinella longiceps, from three localities along the western coast of India was studied by starch-gel electrophoresis. Out of 19 loci scored, no locus was polymorphic by the 95% criterion. Seven loci were polymorphic at the P=0.99 level. The average heterozygosity ranged from 0.6% to 0.9%. These values are very low compared with those of other marine fish species.

scholarly journals A preliminary study of the allozyme variation in the grey hamster, Cricetulus migratorius (Mammalia: Rodentia), from the Asian part of Turkey

2011 ◽  
Vol 63 (2) ◽  
pp. 381-391 ◽  
Author(s):  
Osman İbiş ◽  
Coşkun Tez ◽  
Servet Özcan ◽  
Metin Kiliç ◽  
Murat Telcioğlu
Keyword(s):  
Genetic Variation ◽  
Gene Flow ◽  
Gel Electrophoresis ◽  
Allozyme Variation ◽  
Genetic Distances ◽  
Average Value ◽  
Enzyme Systems ◽  
The Mean ◽  
Preliminary Study ◽  
Allozyme Loci

The aim of the present study was to evaluate the degree of genetic variation and divergence by cellulose acetate gel electrophoresis between samples of Cricetulus migratorius, a cricetine rodent distributed in the Asian part (Anatolia) of Turkey. Out of twenty allozyme loci scored for fifteen enzyme systems, eleven loci were detected to be polymorphic in at least one locality of the Turkish C. migratorius. Indices of genetic variability (the percentage of polymorphic loci, mean number of alleles per locus, and mean observed and expected heterozygosities) were found to be P(95%) = 28, A = 1.3, Ho = 0.226 and He = 0.218, respectively. Nei?s unbiased genetic distances ranged from 0.000 to 0.153, with an average value of 0.069. The mean gene flow was calculated to be Nm = 0.7484. This is a preliminary study describing the allozymic variations of C. migratorius from Turkey. As there are no extensive data on the allozymic variations of C. migratorius from other regions, our results could not be compared, in detail with those of other populations of the species C. migratorius.

Genotypic Diversity of Kikuyugrass (Pennisetum clandestinum) Populations in California

Weed Science ◽  
1995 ◽  
Vol 43 (2) ◽  
pp. 209-214 ◽  
Author(s):  
Cheryl A. Wilen ◽  
Jodie S. Holt ◽  
Norman C. Ellstrand ◽  
Ruth G. Shaw
Keyword(s):  
Genetic Variation ◽  
Genetic Variability ◽  
Plant Species ◽  
Gel Electrophoresis ◽  
Genotypic Diversity ◽  
Clonal Reproduction ◽  
Golf Course ◽  
Starch Gel Electrophoresis ◽  
Geographic Locations ◽  
Starch Gel

Using starch gel electrophoresis, we examined the genetic variability of kikuyugrass collected from three golf course sites within its geographical range in California. These experiments were conducted to determine the method of spread of kikuyugrass in areas where it is considered invasive. Samples from roughs and fairways of each of these locations were compared. of the 354 plants examined, 12 different genotypes were identified by isozyme analysis, and only three of the nine putative loci varied among the genotypes. Two genotypes, representing 73% of the plants examined, were found at all three geographic locations. Our results imply that under common golf course practices, kikuyugrass is maintained by clonal reproduction. We conclude that low genetic variation does not preclude a plant species from being an aggressive invader.

Allozyme divergence and evolutionary relationships among Populus deltoides, P. nigra, and P. maximowiczii

Genome ◽  
1990 ◽  
Vol 33 (1) ◽  
pp. 44-49 ◽  
Author(s):  
Om P. Rajora ◽  
Louis Zsuffa
Keyword(s):  
Gel Electrophoresis ◽  
Populus Deltoides ◽  
Genetic Identity ◽  
Starch Gel Electrophoresis ◽  
Root Tips ◽  
Frequency Distributions ◽  
Starch Gel ◽  
The Mean ◽  
Populus Species ◽  
Allozyme Loci

Horizontal starch gel electrophoresis of enzymes was used to study genetic divergence among Populus deltoides Marsh. (section Aigeiros Duby, Salicaceae), P. nigra L. (section Aigeiros), and P. maximowiczii Henry (section Tacamahaca Spach.) at 37 to 40 allozyme loci coding for 12 enzyme systems in root tips. These three Populus species were genetically distinct from each other. Populus deltoides, P. nigra, and P. maximowiczii had mutually exclusive alleles at two loci, and each of these species had unique alleles at many loci. Certain allozyme loci were detected only in one or two of these species. Frequency distributions of allozyme loci were bimodal with respect to genetic identity for comparisons between any two species. The mean genetic distance was 0.36 ± 0.10 between P. deltoides and P. nigra, 0.39 ± 0.09 between P. deltoides and P. maximowiczii, and 0.34 ± 0.10 between P. nigra and P. maximowiczii. The enzyme electrophoretic evidence indicated a monophyletic origin of the three Populus species.Key words: poplars, genetic identity and divergence, allozymes, molecular evolution, phylogenetics.

Genetic variation in 26 populations of Racospermaauriculiforme and Racospermamangium using allozymes

1994 ◽  
Vol 24 (6) ◽  
pp. 1123-1132 ◽  
Author(s):  
P.D. Khasa ◽  
W.M. Cheliak ◽  
J. Bousquet
Keyword(s):  
Genetic Diversity ◽  
Genetic Distance ◽  
Unknown Origin ◽  
Population Level ◽  
Genetic Distances ◽  
Starch Gel Electrophoresis ◽  
Introduced Populations ◽  
Linear Relationships ◽  
Starch Gel ◽  
The Mean

Racospermaauriculiforme (Cunn. ex Benth.) Pedley and Racospermamangium (Willd.) Pedley are two fast-growing multipurpose leguminous species that have great potential for reforestation in the subhumid and humid tropics. The level and distribution of genetic variability were evaluated among and within 13 populations of each species at 18 loci encoding 10 enzymes, using starch gel electrophoresis. At the population level, the mean number of alleles per locus, the mean percentage of polymorphic loci, and mean expected heterozygosity were, respectively, 1.9, 52.1%, and 0.122 for R. auriculiforme, and 1.5, 24.3%, and 0.064 for R. mangium. Therefore, R. mangium appeared genetically depauperate compared with R. auriculiforme. The proportion of the total genetic diversity that resided among populations in R. auriculiforme (18%) was twice that in R. mangium (9%). No linear relationships were detected between genetic and geographic distances among populations. Cluster analysis of Nei's genetic distances and discriminant analysis did not show any significant geographic pattern of population differentiation for R. mangium. These same analyses revealed two distinct clusters of populations for R. auriculiforme, one in Queensland, Australia, and Papua New Guinea, and the other in the Northern Territory of Australia and Indonesia. For both taxa, seed of unknown origin of some introduced populations in Zaire and Congo could be identified. The genetic distance between the two species (D = 0.097) was, as expected, much larger than the average intraspecific genetic distance derived from comparisons of conspecific populations (D = 0.034 for R. auriculiforme and D = 0.007 for R. mangium). However, the amplitude of the interspecific genetic distance calculated is representative of divergence levels usually observed among subspecific taxa. Based on this, and the lower levels of genetic diversity found in R. mangium, it is suggested that R. mangium derived recently from R. auriculiforme.

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