scholarly journals LOW GENE VARIATION IN DROSOPHILA BUSCKII

Genetics ◽  
1973 ◽  
Vol 75 (3) ◽  
pp. 571-576
Author(s):  
Satya Prakash
Keyword(s):  
Allozyme Variation ◽  
The Other ◽  
Polymorphic Loci ◽  
Domestic Species ◽  
Gene Variation ◽  
Food Niche ◽  
Drosophila Busckii

ABSTRACT Study of allozyme variation in D. busckii at thirty loci gives the proportion of polymorphic loci =.166 and the proportion of loci heterozygous per individual =.044. D. busckii has a narrower seasonal and food niche than the other domestic species D. melanogaster which has more allozyme variation. It is suggested that the low gene variation in D. busckii might be due to adaptation of this species to a narrow niche.

scholarly journals POPULATION GENETIC CONSEQUENCES OF FEEDING HABITS IN SOME FOREST LEPIDOPTERA

Genetics ◽  
1979 ◽  
Vol 92 (3) ◽  
pp. 1005-1021
Author(s):  
Charles Mitter ◽  
Douglas J Futuyma
Keyword(s):  
Genetic Variation ◽  
Environmental Heterogeneity ◽  
Feeding Habits ◽  
Functional Relation ◽  
Allozyme Variation ◽  
Unexpected Result ◽  
Polymorphic Loci ◽  
Allozyme Loci ◽  
Race Formation ◽  
Relationship Of

ABSTRACT By surveying variation at allozyme loci in several phytophagous lepidopteran species (Geometridae), we have tested two hypotheses about the relationship of genetic variation to environmental heterogeneity: (1) that allozyme polymorphisms may exist because of associations between genotypes and "niches" (different host plants, in this instance), and (2) that the overall genetic variation of a species is correlated with environmental heterogeneity (or breadth of the species' overall ecological niche) .—Genetic differentiation among samples of oligophagous or polyphagous species taken from different host species was observed in one of three species, at only one of seven polymorphic loci. The data thus provide no evidence for pronounced genetic sub-structuring, or "host race" formation in these sexually reproducing species, although host plant-genotype associations in a parthenogenetic moth give evidence of the potential for diversifying selection.—In a comparison of allozyme variation in polyphagous ("generalized") and oligophagous ("specialized") species, heterozygosity appeared to be higher in specialized species, at all polymorphic loci but one. I t is possible that this unexpected result arises from a functional relation between breadth of diet and genetic variation.

scholarly journals Genetic variability in four samples of Neoplecostomus yapo (Teleostei: Loricariidae) from the rio Paranapanema basin, Brazil

2009 ◽  
Vol 7 (1) ◽  
pp. 25-30 ◽  
Author(s):  
Juliana S. Philippsen ◽  
Erasmo Renesto ◽  
Ana Maria Gealh ◽  
Roberto F. Artoni ◽  
Oscar A. Shibatta ◽  
...  
Keyword(s):  
Genetic Variability ◽  
Genetic Distance ◽  
Corn Starch ◽  
The Other ◽  
Allozyme Electrophoresis ◽  
Polymorphic Loci ◽  
Two Samples ◽  
Starch Gel ◽  
The Mean ◽  
Electrophoresis Technique

Four samples of Neoplecostomus yapo were analyzed through the allozyme electrophoresis technique in corn starch gel. The allozyme pattern was similar to those found in N. paranensis with 24 loci scored. Two samples (ribeirão Atlântico and ribeirão Uraí) showed monomorphic bands for all 24 loci, whereas the other two (rio Verde and rio Fortaleza) showed 8.3% of polymorphic loci. The He genetic variability estimates for the rios Verde and Fortaleza populations were 0.0195 and 0.0179, respectively, too much inferior to the mean heterozygosity summed to species from the whole world (0.051). The Wright statistical values F IS = 0.5181, F IT = 0.5681 and F ST = 0.1039 and the genetic distance of Nei values showed that the four samples are genetically very similar to each other and that there is homozygote excess in the polymorphic loci.

Genetic structure of the western rock lobster, Panulirus cygnus, with the benefit of hindsight

1996 ◽  
Vol 47 (7) ◽  
pp. 889 ◽  
Author(s):  
AP Thompson ◽  
JR Hanley ◽  
MS Johnson
Keyword(s):  
Genetic Structure ◽  
Western Australia ◽  
Allozyme Variation ◽  
Genetic Homogeneity ◽  
Latitudinal Variation ◽  
Rock Lobster ◽  
Polymorphic Loci ◽  
Allelic Frequencies ◽  
Genetic Subdivision ◽  
Panulirus Cygnus

Allozyme variation was used to investigate the genetic structure of the western rock lobster, Panulirus cygnus, along the coast of Western Australia. The study involved genetic surveys in 1980 and 1994. The first survey showed strong suggestions of latitudinal variation at two polymorphic loci, EST and GPI, but these suggestions were statistically suspect. With the benefit of hindsight gained from 1980, the 1994 survey was designed to examine more directly the suggestion of latitudinal genetic subdivision in this species. No evidence of genetic subdivision was found at either the EST or the GPI locus. In addition, the average FST value over nine polymorphic loci was a very low 0.0002. The evidence is consistent with current interpretations that P. cygnus is a single, panmictic population. In contrast with this spatial genetic homogeneity, however, there were significant changes in allelic frequencies at the GPI locus between 1980 and 1994, indicating genetic differences among cohorts.

Seasonal variation and clonal selection in cyclically parthenogenetic rose aphids (Macrosiphum rosae)

1985 ◽  
Vol 27 (2) ◽  
pp. 224-232 ◽  
Author(s):  
L. R. Rhomberg ◽  
S. Joseph ◽  
R. S. Singh
Keyword(s):  
Genetic Variation ◽  
Seasonal Variation ◽  
Clonal Selection ◽  
Natural Populations ◽  
Allozyme Variation ◽  
Polymorphic Loci ◽  
Esterase Loci ◽  
Allozyme Loci ◽  
Macrosiphum Rosae ◽  
Asexual Cycle

Patterns of geographic and seasonal genetic variation were assessed in natural populations of cyclically parthenogenetic rose aphids Macrosiphum rosae (L.). Nine populations were studied for a red–green colour morph and 30 allozyme loci (20 coding for enzymes and 10 for abundant proteins). Genetic variation was found at 5 of 20 enzyme loci (20%); all 10 abundant proteins proved monomorphic. The average heterozygosity was 4.3%. At some polymorphic loci genotypic frequencies showed significant deviations from Hardy–Weinberg proportions. Six local populations from Hamilton, Ontario, were studied for seasonal variation at the colour locus and at two polymorphic esterase loci (Est-2 and Est-4). All three loci showed large changes in genotypic frequencies over the season during the asexual cycle, but only for Est-4 were changes consistent among populations. This locus undergoes a regular seasonal cycle, the directional changes during the asexual phase presumably being balanced by changes during the sexual phase. The frequencies of three-locus genotypes within each locality fluctuated dramatically over the course of a season, reflecting the domination of local infestations by a few particularly successful clones. We speculate that because of such clonal competition followed by extensive migration, much of the selectively neutral variation is purged from aphid populations. The remaining polymorphic loci, which are mostly di- or tri-allelic, are subject to balancing natural selection at the gene or at closely linked loci. The Est-4 in rose aphids is an example of such a selectively maintained polymorphism.Key words: aphids, allozyme variation, seasonal variation, parthenogenesis, clonal selection, population structure.

Highly repeated DNA and allozyme variation between sibling species: evidence for introgression

Genome ◽  
1987 ◽  
Vol 29 (2) ◽  
pp. 272-279 ◽  
Author(s):  
M. L. Arnold ◽  
P. Wilkinson ◽  
D. D. Shaw ◽  
A. D. Marchant ◽  
N. Contreras
Keyword(s):  
Sibling Species ◽  
Dna Sequences ◽  
Clustering Analysis ◽  
Introgressive Hybridization ◽  
Allozyme Variation ◽  
The Other ◽  
Repeated Dna ◽  
Highly Repeated Dna ◽  
Pattern Of Variation ◽  
Two Populations

The Caledia captiva complex of grasshoppers includes two sibling species along with two subspecies. Two populations (Papuan Torresian and Daintree) representing the two sibling species were found to share six allozyme characters and a highly repeated DNA family not found in any of the other Caledia taxa. These two populations showed genic divergence that was equivalent to comparisons between the two subspecies from the complex. Sequenced, cloned repeats from the Papuan Torresian and Daintree taxa showed equivalent variation for both intra- and inter-specific comparisons. A phenetic clustering analysis did not separate the repeats from these two taxa into different clades. Furthermore, the overall genomic organization of the sequence family in the two species is very similar, although the repeats are cytologically dispersed in one form (Papuan Torresian) and clustered in the other form (Daintree). It is argued that the most likely evolutionary explanation for the observed pattern of variation in the allozymes and highly repeated DNA sequences between these types is introgressive hybridization. The possible consequences of such an event are discussed in light of the population genetics and distribution of the present day Caledia taxa. Key words: highly repeated DNA, Caledia, grasshopper, allozymes.

Geographic variability and wing plasticity in Sitona sulcifrons (Coleoptera: Curculionidae)

1994 ◽  
Vol 84 (2) ◽  
pp. 269-273
Author(s):  
Tomáš Pavlíček
Keyword(s):  
Gene Flow ◽  
Phenotypic Plasticity ◽  
Genetic Variability ◽  
Relative Size ◽  
The Other ◽  
Wing Size ◽  
Geographic Variability ◽  
Polymorphic Loci ◽  
Local Populations ◽  
Total Variability

AbstractGenetic variability in four polymorphic loci and variation in phenotypic plasticity in relation to the relative size of wings, were compared and contrasted among eight local populations of Sitonasulcifrons Thunberg from the Czech and Slovak republics. The distances between localities from which samples were taken were between 49 and 492 kilometres. The results demonstrated that: 1. The variability between populations was 5.5% and the other 94.5% of the total variability was realized within populations. 2. Significant differences in allozyme frequencies among populations existed when distances were more than 100 km. A similar trend was also found in variability of relative wing size in males among populations when distances were more than 200 km. 3. Overall, a significant deficiency of heterozygotes in relation to Hardy-Weinberg predictions existed from all samples. The results support the idea that, at least inagricultural areas, gene flow in S. sulcifrons does not seem to be strong enough to stabilize one large interbreeding population in distances over 100 kilometres.

Genetically distinct sympatric populations of resident and anadromous Atlantic salmon, Salmo salar

1989 ◽  
Vol 67 (6) ◽  
pp. 1453-1461 ◽  
Author(s):  
E. Verspoor ◽  
L. J. Cole
Keyword(s):  
Life History ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
River System ◽  
Population Variation ◽  
The Other ◽  
Gene Pools ◽  
Sympatric Populations ◽  
Polymorphic Loci ◽  
Atlantic Salmon Salmo Salar

Atlantic salmon (Salmo salar) from Little Gull Lake on the Gander River system of central Newfoundland were found to be electrophoretically polymorphic at 5 of 20 protein loci screened. Four of the polymorphic loci were structural and one was regulatory. Major heterozygote deficiencies relative to Castle–Hardy–Weinberg expectations were detected at the two most polymorphic loci, Aat-3 and Mdh-3,4, and significant nonrandom associations between genotypes at these loci and the other polymorphic loci, Sdh-1, Me-2, and Pgm1-t, were also found. The heterozygote deficiencies and the nonrandom genotype associations were attributable to the admixture of genetically distinct gene pools of resident and anadromous salmon in the lake. This is the first documented case of coexistence of reproductively separated populations of Atlantic salmon of the two life history types, and shows that the sympatric occurrence of the two forms can represent between-population variation.

Genetics of allozyme variation in Cuphea lanceolata Ait.

Genome ◽  
1989 ◽  
Vol 32 (1) ◽  
pp. 57-63 ◽  
Author(s):  
S. J. Knapp ◽  
L. A. Tagliani
Keyword(s):  
Goodness Of Fit ◽  
Capric Acid ◽  
Allozyme Variation ◽  
Test Statistics ◽  
Shikimate Dehydrogenase ◽  
Average Heterozygosity ◽  
Goodness Of Fit Test ◽  
Polymorphic Loci ◽  
Segregation Ratios ◽  
Cuphea Lanceolata

Genetic markers are needed for mating systems and breeding experiments in Cuphea lanceolata Ait.; however, none have been described in this species. Allozyme variation was analyzed among 14 F2 populations assayed for aconitase (ACO), diaphorase (DIA), esterase (EST), fluorescent esterase transaminase (FEST), glutamine oxaloacetate transaminase (GOT), menadione reductase (MNR), phosphoglucomutase (PGM), phosphoglucose isomerase (PGI), and shikimate dehydrogenase (SKDH) enzyme activity. At least 23 loci were resolved in these enzyme systems: 6 monomorphic loci, 5 poorly resolved loci, and 12 clearly resolved polymorphic loci. Observed segregation ratios were generally not significantly different (P > 0.05) from expected segregation ratios; however, segregation distortion was observed at Skdh-1 and Mnr-1 (Dia-1) in some F2 populations. Skdh-1 and Pgm-2 and Est-1, Est-2, Fest-1, and Mnr-1 comprise putative linkage groups. Allozyme variation was observed between and within accessions. The expected average heterozygosity was 16.3%. There were one to eight polymorphic loci among the F2 populations analyzed. There were an average of 2.05 alleles per locus. Several useful codominant markers were identified and a partial allozyme linkage map was constructed. Additional work is needed to revise and complete the map.Key words: Cuphea, isozymes, goodness of fit test statistics, lauric acid, capric acid.

scholarly journals ALLOZYME DIVERSITY IN CHESTNUT (CASTANEA SPP.).

HortScience ◽  
1994 ◽  
Vol 29 (7) ◽  
pp. 736a-736
Author(s):  
Hongwen Huang ◽  
Fenny Dane ◽  
Joseph Norton
Keyword(s):  
Genetic Variability ◽  
Genetic Distance ◽  
The Other ◽  
Changjiang River ◽  
Allozyme Diversity ◽  
Allele Distribution ◽  
Polymorphic Loci ◽  
The Changjiang River ◽  
Enzyme Systems ◽  
River Region

Allozyme genetic variability in three chestnut (Castanea) species was investigated using 19 loci from ten enzyme systems. G-tests of heterogeneity of isozymic allele distribution showed significant differences in both intraspecific and interspecific populations. C. mollissima was found to possess a significantly higher value of mean gene heterozygosity (H=0.3050±0.0419), percentage of polymorphic loci (P=84.21%) and average number of alleles per locus (A=2.05) than any other species in the Castanea section Eucustanon. When the genetic variability of populations of C. mollissimo from four regions in China was investigated, population from the Changjiang river region showed a markedly higher mean gene heterozygosity (H=0.3480±0.0436) than populations from the other regions. An approximately identical genetic distance between the population from the Changjiang river region and populations from three other regions was observed, while populations from the latter regions showed almost the same genetic distance from each other.

Allozyme variation and geographic differentiation in the Chilean leptodactylid frog Batrachyla taeniata (Girard, 1854)

2001 ◽  
Vol 22 (4) ◽  
pp. 413-420 ◽  
Author(s):  
Lila Brieva ◽  
J. Ramón Formas
Keyword(s):  
Genetic Distance ◽  
Isolation By Distance ◽  
Allozyme Variation ◽  
Geographic Differentiation ◽  
Geographical Distance ◽  
Electrophoretic Variation ◽  
Statistics Analysis ◽  
Polymorphic Loci ◽  
The Mean ◽  
F Statistics

AbstractElectrophoretic variation in proteins encoded by 15 loci was analyzed in nine populations of the Chilean leptodactylid frog Batrachyla taeniata. The overall proportion of polymorphic loci was estimated to be 16.2% and the average number of alleles per locus, 1.18. The mean observed and expected heterozygosities for the populations were 0.9% and 5.9%, respectively. The average Rogers genetic distance among pairs of populations was 0.105. F statistics analysis showed high levels of genetic subdivision (Fst = 0.450). An isolation-by-distance test indicated significant correlation between genetic and geographical distance. Resumen. Se analizó la variabilidad electroforética de proteínas codificadas por 15 loci en nueve poblaciones de la rana leptodactílida chilena Batrachyla taeniata. La proporción general de loci polimórficos se estimó en 16,2% y el número promedio de alelos por locus en 1,18. Las heterocigosidades observadas y esperadas promedio fueron 0,9% y 5,9% respectivamente. El promedio de la distancia de Rogers entre pares de poblaciones fue 0,105. El análisis estadístico de F mostró altos niveles de subdivisión genética (Fst = 0,450). El análisis del aislamiento por distancia indicó una correlación significativa entre la distancia genética y la distancia geográfica.

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