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.

scholarly journals ENZYME VARIABILITY IN THE DROSOPHILA WILLISTONI GROUP. IV. GENIC VARIATION IN NATURAL POPULATIONS OF DROSOPHILA WILLISTONI

Genetics ◽  
1972 ◽  
Vol 70 (1) ◽  
pp. 113-139
Author(s):  
Francisco J Ayala ◽  
Jeffrey R Powell ◽  
Martin L Tracey ◽  
Celso A Mourão ◽  
Santiago Pérez-Salas
Keyword(s):  
Genetic Variation ◽  
Central America ◽  
West Indies ◽  
Allelic Variation ◽  
Natural Populations ◽  
Group Iv ◽  
The West ◽  
Drosophila Willistoni ◽  
Genic Variation ◽  
South Brazil

ABSTRACT We describe allelic variation at 28 gene loci in natural populations of D. willistoni. Seventy samples were studied from localities extending from Mexico and Florida, through Central America, the West Indies, and tropical South America, down to South Brazil. At least several hundred, and often several thousand, genomes were sampled for each locus. We have discovered a great deal of genetic variation. On the average, 58% loci are polymorphic in a given population. (A locus is considered polymorphic when the frequency of the most common allele is no greater than 0.95). An individual fly is heterozygous, on the average, at 18.4% loci.—Concerning the pattern of the variation, the most remarkable finding is the similarity of the configuration of allelic frequencies from locality to locality throughout the distribution of the species. Our observations support the conclusion that balancing natural selection is the major factor responsible for the considerable genetic variation observed in D. willistoni.

Studies of the inheritance of bovine serum transferrins

1964 ◽  
Vol 6 (1) ◽  
pp. 107-117 ◽  
Author(s):  
G. A. E. Gall ◽  
R. T. Berg
Keyword(s):  
Gel Electrophoresis ◽  
Bovine Serum ◽  
Embryonic Mortality ◽  
Genetic Mechanism ◽  
Starch Gel Electrophoresis ◽  
Gene Frequencies ◽  
Starch Gel ◽  
Cattle Herds

SUMMARY1. The transferrins in two cattle herds were studied by means of starch gel electrophoresis. Three phenotypes were observed in a Hereford herd and six in a Hybrid herd comprised of Galloway, Aberdeen Angus and Charolais breeds.2. Gene frequencies were calculated for each herd. Great variation was found in the frequency of the transferrin alleles between breed and source within the Hybrid herd and between the Hybrid and Hereford herds. The frequencies of the transferrin alleles found in the cows in the Hereford herd were TfA = 0·467 and TfD = 0·533; those found in the cows in the Hybrid herd were TfA = 0·382, TfD = 0·506 and TfE = 0·112.3. Progeny data were in general agreement with the three-allele theory of inheritance, although the data suggested that offspring in the Hybrid herd carrying the TfE allele occurred at a lower frequency than expected.4. The possible relation of transferrin type to embryonic mortality was studied. The results were in general agreement with those of other workers, indicating a possible interaction between the genotypes of the foetus and dam.5. The characteristics of the transferrin types and the postulated three-allele genetic mechanism for the control of the observed variation are discussed.

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

scholarly journals Haemoglobin polymorphism in selected farm animals: A review

2014 ◽  
Vol 30 (3) ◽  
pp. 377-390 ◽  
Author(s):  
S.S.A. Egena ◽  
R.O. Alao
Keyword(s):  
Genetic Improvement ◽  
Raw Materials ◽  
Farm Animals ◽  
Starch Gel Electrophoresis ◽  
Gene Frequencies ◽  
Starch Gel ◽  
And Performance ◽  
Polypeptide Chains ◽  
Degree Of Similarity

Biochemical diversity or polymorphism is the occurrence of varieties attributed to biochemical differences which are under genetic control. It has created a leeway for the genetic improvement of farm animals. This is because it can be used as a useful tool for the characterization of livestock breeds and population. This way, the degree of similarity or differences within and between breeds can be ascertained and this differences or similarity are important raw materials for genetic improvement of animals. Data obtained on gene frequencies and genotypes through polymorphism study makes it not only possible to compare the gene stocks of animals, the possible effects of the genes on reproductive and performance traits, but also study genetic variability under different environmental conditions of selection. This study was carried out to review haemoglobin (Hb) polymorphism in selected farm animals with the view of finding out the type of polymorphism observed by starch gel electrophoresis due to variation in the amino acid sequence in the polypeptide chains of Hb. The review showed clearly that there is a gene-controlled diversity in the different farm animals considered. This could serve as a reference point for future studies earmarked for the improvement of the animals possibly via marker-assisted selection.

scholarly journals The molecular through ecological genetics of abnormal abdomen. IV. Components of genetic variation in a natural population of Drosophila mercatorum.

Genetics ◽  
1992 ◽  
Vol 130 (2) ◽  
pp. 355-366
Author(s):  
H Hollocher ◽  
A R Templeton ◽  
R DeSalle ◽  
J S Johnston
Keyword(s):  
Genetic Variation ◽  
Natural Population ◽  
Allelic Variation ◽  
Natural Populations ◽  
Developmental Time ◽  
Ecological Genetics ◽  
Adult Longevity ◽  
Genetic Determinants ◽  
Drosophila Mercatorum ◽  
Y Chromosomes

Abstract Natural populations of Drosophila mercatorum are polymorphic for a phenotypic syndrome known as abnormal abdomen (aa). This syndrome is characterized by a slow-down in egg-to-adult developmental time, retention of juvenile abdominal cuticle in the adult, increased early female fecundity, and decreased adult longevity. Previous studies revealed that the expression of this syndrome in females is controlled by two closely linked X chromosomal elements: the occurrence of an R1 insert in a third or more of the X-linked 28S ribosomal genes (rDNA), and the failure of replicative selection favoring uninserted 28S genes in larval polytene tissues. The expression of this syndrome in males in a laboratory stock was associated with the deletion of the rDNA normally found on the Y chromosome. In this paper we quantify the levels of genetic variation for these three components in a natural population of Drosophila mercatorum found near Kamuela, Hawaii. Extensive variation is found in the natural population for both of the X-linked components. Moreover, there is a significant association between variation in the proportion of R1 inserted 28S genes with allelic variation at the underreplication (ur) locus such that both of the necessary components for aa expression in females tend to cosegregate in the natural population. Accordingly, these two closely linked X chromosomal elements are behaving as a supergene in the natural population. Because of this association, we do not believe the R1 insert to be actively transposing to an appreciable extent. The Y chromosomes extracted from nature are also polymorphic, with 16% of the Ys lacking the Y-specific rDNA marker. The absence of this marker is significantly associated with the expression of aa in males. Hence, all three of the major genetic determinants of the abnormal abdomen syndrome are polymorphic in this natural population.

Enzyme variation in the Anopheles gambiae Giles group of species (Diptera: Culicidae)

1978 ◽  
Vol 68 (1) ◽  
pp. 85-97 ◽  
Author(s):  
S. J. Miles
Keyword(s):  
Anopheles Gambiae ◽  
Natural Populations ◽  
Lactic Dehydrogenase ◽  
Starch Gel Electrophoresis ◽  
Malic Dehydrogenase ◽  
Glycerophosphate Dehydrogenase ◽  
Starch Gel ◽  
Anopheles Gambiae Giles ◽  
Species Specific ◽  
Glucose 6 Phosphate Dehydrogenase

AbstractThe genotypes of chromosomally-identified individuals from natural populations of the known species of the group of Anopheles gambiae Giles were scored for the enzyme protein structural loci coding for adenylate kinase (Adk), α-naphthyl acetate esterase (Est-1, Est-2, Est-3), glutamic-oxaloacetic transaminase (Got), α-glycerophosphate dehydrogenase (αGpd), hexokinase (Hk), isocitric dehydrogenase (Idh), lactic dehydrogenase (Ldh), ‘leucine’ aminopeptidase (Lap-2), malic enzyme (Me), octanol dehydrogenase (Odh), phosphoglucomutase (Pgm-1, Pgm-2), 6-phosphogluconic dehydrogenase (6-Pgd), phosphohexose isomerase (Phi) and superoxide dismutase (Sod), following starch gel electrophoresis. In the material examined, Est-1, Est-2, Est-3, Got, ldh, Lap-2, Odh, Pgm-1, Pgm-2 and Sod were segregating for two or more alleles; unique alleles at the Est-1, Got and Sod loci produced species-specific phenotypes in A. melas (Theo.), species C and species D, respectively. The further sampling of A. merus Dön, populations supported the presence of a unique SOD phenotype by which this species can also be identified. Of the other enzyme systems examined, no activity following electrophoresis was detected for aldolase and fructose-1,6-diphosphatase, and the resolution of acid and alkaline phosphatase, glyceraldehyde-3-phosphate dehydrogenase, glucose-6-phosphate dehydrogenase, malic dehydrogenase and xanthine dehydrogenase was too poor under the particular electrophoretic conditions for genetic analyses of the enzyme phenotypes.

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.

The Red Cell Acid Phosphatase Polymorphism in Greek b-Thalassemia Patients

1975 ◽  
Vol 24 (3-4) ◽  
pp. 337-338
Author(s):  
A. Kalos ◽  
K. Melissinos ◽  
A. Archimandritis ◽  
G. Kourounis ◽  
B. Angelopoulos
Keyword(s):  
Acid Phosphatase ◽  
Gel Electrophoresis ◽  
Starch Gel Electrophoresis ◽  
Red Cell ◽  
Gene Frequencies ◽  
Starch Gel ◽  
Acid Phosphatase Polymorphism ◽  
Cell Acid

Red cell acid phosphatase polymorphism was studied by starch gel electrophoresis in 70 b-thalassemia patients and in 310 healthy Greeks. Our results gave the following gene frequencies: b-thalassemia patients: pa 0.321, pb 0.643, pc 0.036; healthy Greeks: pa 0.302, pb 0.653, pc 0.045. No statistically significant differences were found between the two groups.

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