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.

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 diversity in red pine: evidence for low genic heterozygosity

1977 ◽  
Vol 7 (2) ◽  
pp. 343-347 ◽  
Author(s):  
D. P. Fowler ◽  
R. W. Morris
Keyword(s):  
Genetic Diversity ◽  
Gel Electrophoresis ◽  
Allozyme Variation ◽  
Red Pine ◽  
Starch Gel Electrophoresis ◽  
Banding Patterns ◽  
Coniferous Species ◽  
Low Degree ◽  
Starch Gel ◽  
Genetically Determined

Starch gel electrophoresis was used to survey for genetically determined enzyme mobility differences among 297 megagametophytes of red pine (Pinusresinosa Ait.) from five widely separated geographical sources. Consistent and reproducible enzyme banding patterns were observed with five of the seven isozyme systems assayed. No variation in band mobility was observed in any of these systems. This result stands in contrast with those reported from surveys of allozyme variation in other coniferous species but is consistent with the low degree of genetic variation observed in red pine for higher levels of genetic organization. It is concluded that red pine is genetically depauperate.Possible explanations for restricted genetic diversity are discussed. The most plausible explanation suggests that red pine was at sometime, possibly during the Pleistocene, reduced to a small refugial population and has yet to reestablish equilibrium heterozygosity.

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.

scholarly journals Enzyme variability in the Drosophila willistoni Group. V. Genic variation in natural populations of Drosophila equinoxialis

1972 ◽  
Vol 20 (1) ◽  
pp. 19-42 ◽  
Author(s):  
Francisco J. Ayala ◽  
Jeffrey R. Powell ◽  
Martin L. Tracey
Keyword(s):  
Genetic Variation ◽  
Allelic Variation ◽  
Natural Populations ◽  
Starch Gel Electrophoresis ◽  
Gene Frequencies ◽  
Group V ◽  
Neutral Genetic Variation ◽  
Starch Gel ◽  
Genic Variation ◽  
Standard Techniques

SUMMARYWe have studied genetic variation at 27 loci in 42 samples from natural populations of a neotropical species, Drosophila equinoxialis, using standard techniques of starch-gel electrophoresis to detect allelic variation in genes coding for enzymes. There is considerarle genetic variability in D. equinoxialis. We have found allelic variation in each of the 27 loci, although not in every population. On the average, 71% of the loci are polymorphic – that is, the most common allele has a frequency no greater than 0·95 – in a given population. An individual is heterozygous on the average at 21·8% of its loci.The amount of genetic variation fluctuates widely from locus to locus. At the Mdh-2 locus arout 1% of the individuals are heterozygotes; at the other extreme more than 56% of the individuals are heterozygous at the Est-3. At any given locus the configuration of allelic frequencies is strikingly similar from locality to locality. At each and every locus the same allele is generally the most common throughout the distribution of the species. Yet differences in gene frequencies occur between localities. The pattern of genetic variation is incompatible with the hypothesis that the variation is adaptively neutral. Genetic variation in D. equinoxialis is maintained by balancing natural selection.The amount and pattern of genetic variation is similar in D. equinoxialis and its sibling species, D. willistoni. Yet the two species are genetically very different. Different sets of alleles occur at nearly 40% of the loci.

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.

Genetic variation in populations of the endemic Achillea millefolium ssp. megacephala from the Athabasca sand dunes and the widespread ssp. lanulosa in western North America

1996 ◽  
Vol 74 (7) ◽  
pp. 1138-1146 ◽  
Author(s):  
Brett G. Purdy ◽  
Randall J. Bayer
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Gene Diversity ◽  
Sand Dunes ◽  
Achillea Millefolium ◽  
Starch Gel Electrophoresis ◽  
Widespread Species ◽  
Polymorphic Loci ◽  
Endemic Taxon ◽  
Starch Gel

As part of an analysis of genetic diversity in endemic taxa of the Athabasca sand dunes in northern Saskatchewan, Canada, genetic variation was examined by starch gel electrophoresis in six populations of the endemic Achillea millefolium ssp. megacephala, and 13 populations of the closely related widespread taxon, A. millefolium ssp. lanulosa. Endemic populations had more alleles per locus, a higher percentage of polymorphic loci, and greater genetic diversity than did populations of the widespread taxon. At polymorphic loci, total gene diversity was comparable in both taxa, although within-population gene diversity was higher in the endemic taxon. Population differentiation (GST) was considerably lower in ssp. megacephala than in ssp. lanulosa, although GST values were reduced when the parameter was calculated separately for geographic subdivisions of the widespread taxon. Our results differ from previous studies in which the endemic is typically depauperate of genetic variation relative to related widespread species. We suggest that obligate sexual reproduction and the absence of long-term asexual reproduction may be one of a number of factors that help populations of ssp. megacephala maintain higher levels of genetic variation on the Athabasca sand dunes. Keywords: genetic variation, endemic, rare species, Athabasca sand dunes, Achillea millefolium.

ETUDE DE L'HEREDITE DE PHOSPHATASES ACIDES CHEZ LE DACTYLE (DACTYLIS GLOMERATA) DIPLOIDE ET TETRAPLOIDE

1981 ◽  
Vol 23 (3) ◽  
pp. 513-523 ◽  
Author(s):  
R. Lumaret
Keyword(s):  
Polymorphic Locus ◽  
Natural Populations ◽  
Dactylis Glomerata ◽  
Wild Plants ◽  
Starch Gel Electrophoresis ◽  
Ploidy Levels ◽  
Orchard Grass ◽  
In The Wild ◽  
Starch Gel ◽  
Dactylis Glomerata L

Starch gel electrophoresis of leaves of diploid and more particularly tetraploid orchard grass (Dactylis glomerata L.) from cultivars as well as natural populations disclosed several anodal stable bands with fast migration and phosphatasic activity. Six different phenotypes with one band, many others with three regular bands or six bands (only in the tetraploid individuals), were observed, showing the dimeric structure of the enzymes. Inheritance studies showed one polymorphic locus with six codominant alleles AcPH 11.00, AcPH 10.95, AcPH 10.90, AcPH 10.88, AcPH 11.02 and AcPH 11.04 with differences in enzymatic expression. AcPH 1.00 and AcPH 10.90 have been found in the two ploidy levels. Results from the tetraploid progenies involved tetravalents in meiosis for individuals originating from cultivars but bivalents in the wild plants. The two loci AcPH 1 and GOT 1 (this last one coding for a glutamate oxaloacetate transaminase) are not linked and seem to be located on different chromosomes.

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.

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