Selection For and Against Ethological Isolation Between Drosophila pseudoobscura and Drosophila persimilis

Evolution ◽  
1966 ◽  
Vol 20 (4) ◽  
pp. 634 ◽  
Author(s):  
Seymour Kessler
Genetics ◽  
1985 ◽  
Vol 111 (3) ◽  
pp. 517-554
Author(s):  
Laurence D Mueller ◽  
Lorraine G Barr ◽  
Francisco J Ayala

ABSTRACT We have obtained monthly samples of two species, Drosophila pseudoobscura and Drosophila persimilis, in a natural population from Napa County, California. In each species, about 300 genes have been assayed by electrophoresis for each of seven enzyme loci in each monthly sample from March 1972 to June 1975. Using statistical methods developed for the purpose, we have examined whether the allele frequencies at different loci vary in a correlated fashion. The methods used do not detect natural selection when it is deterministic (e.g., overdominance or directional selection), but only when alleles at different loci vary simultaneously in response to the same environmental variations. Moreover, only relatively large fitness differences (of the order of 15%) are detectable. We have found strong evidence of correlated allele frequency variation in 13-20% of the cases examined. We interpret this as evidence that natural selection plays a major role in the evolution of protein polymorphisms in nature.


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.


1964 ◽  
Vol 5 (1) ◽  
pp. 150-157 ◽  
Author(s):  
Lee Ehrman

Weak but statistically significant sexual isolation has been demonstrated among Vetukhiv's six experimental populations of Drosophila pseudoobscura, all originally descended from founders taken from cultures of the same hybrids from four geographic localities. These six populations were maintained separately for almost 4½ years and then tested for the existence of sexual isolation. The sexual isolation has arisen in the absence of any selection for isolation, evidently as a by-product of genetic divergence.


2003 ◽  
Vol 82 (2) ◽  
pp. 101-106 ◽  
Author(s):  
SOOJIN YI ◽  
BRIAN CHARLESWORTH

We have investigated the pattern of DNA sequence variation at the exuperantia2 locus in Drosophila pseudoobscura. This adds to the increasing dataset of genetic variation in D. pseudoobscura, a useful model species for evolutionary genetic studies. The level of silent site nucleotide diversity and the divergence from an outgroup Drosophila miranda are comparable with those for other X-linked loci. One peculiar pattern at the exu2 locus of D. pseudoobscura is a complete linkage disequilibrium between two SNPs, one of which is a replacement site. As a result, there are two distinct haplotype groups in our dataset. Based upon the comparisons with the outgroup sequences from D. miranda and Drosophila persimilis, we show that the newly derived haplotype group has lower diversity than the ancestral haplotype group. The pattern of protein evolution at exu2 shows some deviation from the neutral model. Together, these and other characteristics of the exu2 locus suggest the action of selection on the pattern of SNP variation, consistent with a partial selective sweep associated with the newly derived haplotype.


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.


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