High frequency of cosmopolitan inversions in natural populations of Drosophila ananassae from Kerala, South India

1984 ◽  
Vol 75 (6) ◽  
pp. 504-505 ◽  
Author(s):  
B. N. Singh
Keyword(s):  
High Frequency ◽  
South India ◽  
Natural Populations ◽  
Drosophila Ananassae

scholarly journals Cytogenetic differentiation between Palearctic and Nearctic populations of Chironomus plumosus L. (Diptera, Chironomidae)

Genome ◽  
1999 ◽  
Vol 42 (5) ◽  
pp. 797-815 ◽  
Author(s):  
Malcolm G Butler ◽  
Iya I Kiknadze ◽  
Veronica V Golygina ◽  
Jon Martin ◽  
Albina G Istomina ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
High Frequency ◽  
Natural Populations ◽  
Inversion Polymorphism ◽  
Chironomus Plumosus ◽  
Chromosomal Banding ◽  
Great Divergence ◽  
Holarctic Species

Macrogeographic patterns of polytene chromosomal banding sequences were studied in natural populations of the Holarctic species Chironomus plumosus. Of the 31 inversion sequences now known, 16 are endemic to the Palearctic, 7 are endemic to the Nearctic, and 8 are Holarctic sequences common to both zoogeographic zones. Differences in the sets of inversion sequences found on each continent, plus differing frequencies of Holarctic sequences, result in great overall divergence of karyotypes on the two continents. The karyotype of Nearctic C. plumosus differs from that of Palearctic populations primarily by the presence of a homozygous Nearctic sequence in arm A (n'plu A9), along with fixation (h'plu C2, h'plu E2, and h'plu F1), or high frequency (h'plu D2), of Holarctic sequences which are present but less frequent in the Palearctic. Although long continental isolation has led to great divergence of karyotypes on opposite sides of the Atlantic Ocean, all populations of C. plumosus show sufficient cytogenetic similarity to constitute a single Holarctic species.Key words: karyotype, inversion polymorphism, cytogenetic distances, Chironomus.

Crossing over does occur in males of Drosophila ananassae from natural populations

Genome ◽  
2012 ◽  
Vol 55 (7) ◽  
pp. 505-511 ◽  
Author(s):  
Beatriz Goñi ◽  
Muneo Matsuda ◽  
Masa-Toshi Yamamoto ◽  
Carlos R. Vilela ◽  
Yoshiko N. Tobari
Keyword(s):  
Natural Populations ◽  
Drosophila Ananassae ◽  
Crossing Over ◽  
Cytological Analysis ◽  
Wild Type ◽  
Cytological Evidence ◽  
Type Strains ◽  
Chromosome Breakages ◽  
Brazilian Populations

Spontaneous crossing over in males of Drosophila ananassae has been well demonstrated using F1 individuals from crosses between marker stocks and wild type strains. However, the question of its occurrence in males from natural populations remained open. Here we present the cytological evidence that crossing over does occur in males of D. ananassae from two Brazilian populations, sampled nearly 21 years apart, and in two recently sampled populations, one from Indonesia and one from Okinawa, Japan. Cytological analysis of meiosis in males collected from nature and in sons of females from the same population inseminated in nature revealed the presence of chiasmata, inversion chiasmata, and isosite chromosome breakages in the diplotene cells in all sampled populations. These data demonstrate that reciprocal and nonreciprocal exchanges and chromosome breakages, previously reported as related events of male crossing over, do occur at variable frequencies among males from natural populations.

scholarly journals Different Mechanisms of Resistance toBacillus thuringiensis Toxins in the Indianmeal Moth

2001 ◽  
Vol 67 (3) ◽  
pp. 1085-1089 ◽  
Author(s):  
Salvador Herrero ◽  
Brenda Oppert ◽  
Juan Ferré
Keyword(s):  
Binding Affinity ◽  
Binding Sites ◽  
High Frequency ◽  
Natural Populations ◽  
Slight Reduction ◽  
Mechanisms Of Resistance ◽  
Drastic Reduction ◽  
Toxin Binding ◽  
Toxicological Studies ◽  
Toxicological Data

ABSTRACT Susceptibility to protoxin and toxin forms of Cry1Ab and the binding of 125I-labeled Cry1Ab and Cry1Ac has been examined in three Plodia interpunctella colonies, one susceptible (688s) and two resistant (198r and Dplr) to Bacillus thuringiensis. Toxicological studies showed that the 198r colony was 11-fold more resistant to Cry1Ab protoxin than to Cry1Ab activated toxin, whereas the Dplr colony was 4-fold more resistant to protoxin versus toxin. Binding results with 125I-labeled toxins indicated the occurrence of two different binding sites for Cry1Ab in the susceptible insects, one of them shared with Cry1Ac. Cry1Ab binding was found to be altered in insects from both resistant colonies, though in different ways. Compared with the susceptible colony, insects from the Dplr colony showed a drastic reduction in binding affinity (60-fold higher Kd ), although they had similar concentrations of binding sites. Insects from the 198r colony showed a slight reduction in both binding affinity and binding site concentration (five-fold-higherKd and ca. three-fold-lowerRt compared with the 688s colony). No major difference in Cry1Ac binding was found among the three colonies. The fact that the 198r colony also has a protease-mediated mechanism of resistance (B. Oppert, R. Hammel, J. E. Throne, and K. J. Kramer, J. Biol. Chem. 272:23473–23476, 1997) is in agreement with our toxicological data in which this colony has a different susceptibility to the protoxin and toxin forms of Cry1Ab. It is noteworthy that the three colonies used in this work derived originally from ca. 100 insects, which reflects the high variability and high frequency of B. thuringiensisresistance genes occurring in natural populations.

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