scholarly journals GENIC HETEROGENEITY AT TWO ALCOHOL DEHYDROGENASE LOCI IN DROSOPHILA PSEUDOOBSCURA AND DROSOPHILA PERSIMILIS

Genetics ◽  
1977 ◽  
Vol 87 (2) ◽  
pp. 285-304
Author(s):  
Jerry A Coyne ◽  
Alexander A Felton

ABSTRACT A sequential electrophoretic survey of the second chromosome loci, alcohol dehydrogenase-6 (Adh-6) and octanol dehydrogenase (Odh), was performed on 147 isochromosomal lines of Drosophila pseudoobscura and 60 lines of its sibling species, D. persimilis. Gels run with a variety of acrylamide concentrations and buffer pH's revealed the presence of 18 alleles of Adh-6 in the two species, where only eight had been previously detected by conventional electrophoretic methods. Only two alleles were added with our techniques to the previous total of nine in both species at the largely monomorphic Odh locus. Both enzymes show a predominance of one allele, with the other variants being fairly rare. There was no evidence of increased genetic divergence between the two species, but we found a striking increase in differentiation of Adh-6 alleles between the main body of D. pseudoobscura populations and the conspecific isolate from Bogotá, Colombia. These results are compared with our previous surveys of xanthine dehydrogenase in these species and discussed in reference to theories of genic polymorphism.

1983 ◽  
Vol 25 (4) ◽  
pp. 370-377 ◽  
Author(s):  
Dennis J. Wogaman ◽  
Marvin B. Seiger

Light preferences for ovipositing of the sibling species Drosophila pseudoobscura and D. persimilis were measured in a multichoice chamber. Behavioral differentiation was found among sympatric populations of D. pseudoobscura and D. persimilis and between allopatric populations of D. pseudoobscura. Differences among isofemale lines within populations indicated genetic variability for the behavior. Both D. pseudoobscura populations were less fecund in a uniform light environment than in the multichoice environment while D. persimilis showed no difference in fecundity in the two environments. The patterns for general photoresponse and ovipositional light response were shown to be different for each population. Thus, the motivation to oviposit may affect photopreference differentially in each population.


1984 ◽  
Vol 26 (3) ◽  
pp. 374-381 ◽  
Author(s):  
David R. Townsend ◽  
Rama S. Singh

Esterase-5 is a highly polymorphic enzyme in Drosophila pseudoobscura and its close relatives. Numerous alleles have been identified by employing a number of physicochemical properties of the enzyme (e.g. electrophoretic mobility, enzyme stability, subunit dimerization, and variation in monomer–dimer equilibrium). Variation in the monomer–dimer equilibrium of esterase-5 leads to differences in electrophoretic mobility of monomers produced by dimers all of which have the same mobility. In this report we have used this criterion to study variation within, as well as between, four closely related species: D. pseudoobscura pseudoobscura, D. pseudoobscura bogotana. D. persimilis, and D. miranda. All lines were characterized for esterase-5 monomer and dimer mobility at a number of gel concentrations and the comparison was made by plotting log10 monomer – dimer mobility as a function of gel concentration. No variation was found within D. p. pseudoobscura or D. p. bogotana but some variation (two distinct alleles) did occur in D. persimilis. Drosophila miranda is segregating for two alleles, one of which is fixed in D. pseudoobscura and the other one is common in D. persimilis. Thus it seems that the variation in monomer–dimer equilibrium is a rather conservative criterion and that the variation in D. miranda is a good deal older than the speciation event(s) which gave rise to D. miranda and the lineage leading to D. pseudoobscura and D. persimilis.Key words: esterase-5, Drosophila pseudoobscura, monomer–dimer equilibrium, population, polymorphism, speciation, electrophoresis.


Genetics ◽  
1980 ◽  
Vol 96 (3) ◽  
pp. 727-741
Author(s):  
R A Norman ◽  
Satya Prakash

ABSTRACT Efforts were made to discriminate new genetic variants among electrophoretic alleles that are associated with chromosome 3 inversions of Drosophila pseudoobscura and D. persimilis. Apparent genetic similarities for electrophoretic alleles between these two species and among the common inversions they carry were reexamined by altering gel concentration and buffer pH. At the amylase locus, the 1.09 electrophoretic allele could be further separated into two allelic classes that differentiated the WT and KL arrangements. Similarly, the 0.84 electrophoretic allele was divided into two allelic classes, one characteristic of the Santa Cruz phylad arrangements, TL and SC, and the other found in strains of the Standard phylad arrangements and CH. Uncommon amylase alleles proved to be different alleles in the two species. No new allelic variants, however, could be found among strains with the amylase 1.00 allele, the commonest allele in the Standard phylad of both species. No major new allelic variation was detected for acid phosphatase-3 and larval protein-10 that revealed any further differentiation among species or inversions. Variation at all three loci in strains of the Bogota population remained genetically similar to variation in strains of mainland D. pseudoobscura.


Genetics ◽  
1976 ◽  
Vol 84 (3) ◽  
pp. 593-607
Author(s):  
Jerry A Coyne

ABSTRACT Acrylamide gel electrophoresis was performed on the enzyme xanthine dehydrogenase in sixty isochromosomal lines of Drosophila persimilis from three geographic populations. Sequential electrophoretic analysis using varied gel concentrations and buffers revealed twenty-three alleles in this species where only five had been described previously. These new electrophoretic techniques also detected a profound increase in divergence of gene frequencies at this locus between D. persimilis and its sibling species D. pseudoobscura. The implications of these results for questions of speciation and the maintenance of genetic variability are discussed.


Genetics ◽  
1977 ◽  
Vol 85 (3) ◽  
pp. 507-511
Author(s):  
David Policansky ◽  
E Zouros

ABSTRACT The sibling species Drosophila pseudoobscura and D. persimilis each carry two gene arrangements in the right arm of the X chromosome; Standard (ST) and Sex Ratio (SR). The SR sequence of D. persimilis and the ST sequence of D. pseudoobscura have the same banding pattern. These cytologically identical arrangements carry different alleles at the esterase-5 (Est-5) and phosphoglucomutase-1 (Pgm-1) loci. All the alleles on the SR arrangement of D. persimilisare also present on the ST arrangement of that species, and the same allele was most common in all cases. However, the allele frequencies at the Pgm-1 locus are significantly different between the two arrangements. Within the ST arrangement of D. persimilis, the alleles at the Est-5 and Pgm-1 loci are in linkage equilibrium.


Genetics ◽  
1980 ◽  
Vol 96 (4) ◽  
pp. 927-938
Author(s):  
David R Wilcox ◽  
Satya Prakash

ABSTRACT Twenty-six D. pseudoobscura strains isogenic for xanthine dehydrogenase alleles from Mesa Verde, Colorado, were tested for differences in the biochemical properties of different allelic forms of xanthine dehydrogenase. No significant differences in binding affinity (Km) or substrate specificity of the enzyme were found. Significant variation among strains, in activity (V  max) and among electromorphs, as well as among strains, in thermolability was found. For the few strains tested, the activity and thermolability differences were shown to co-segregate with the electrophoretic mobility of the variant allele.


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