GEOGRAPHIC VARIATION OF THE CHROMOSOMAL POLYMORPHISM IN DROSOPHILA FLAVOPILOSA

1976 ◽  
Vol 18 (1) ◽  
pp. 111-118 ◽  
Author(s):  
Danko Brncic

Natural populations of the Chilean species Drosophila flavopilosa Frey are polymorphic for the banding sequences in the fifth chromosome due to the existence of four paracentric inversions. Qualitative analysis of the polymorphism demonstrated that there are seasonal fluctuations and geographic variations of two kinds: altitudinal gradients and a north-south gradient. In addition, the northernmost and southernmost samples examined are polymorphic only for one inversion (inversion "B"). In the light of previous experimental evidence, it was concluded that the seasonal fluctuations and elevational differences are probably controlled by weather conditions, especially temperature. However, the observed differences between the central and marginal populations require another type of interpretation, similar to that postulated for other species that exhibit the same pattern of chromosomal variation. A photomicrographic map of the Standard banding pattern of the salivary gland polytene chromosomes of D. flavopilosa is presented.

Genetika ◽  
2007 ◽  
Vol 39 (3) ◽  
pp. 343-354 ◽  
Author(s):  
Víctor Salceda ◽  
Judith Guzmán ◽  
Olga Olvera

Samples of D. pseudoobscura were taken in seventeen localities in Central Mexico inside the parallels 18o - 20o N, with the purpose of determine the chromosomal polymorphism in the third of the different populations of this species. From each captured female a single larva of its offspring was taken, its salivary glands extracted and stained with a solution of aceto orcein to observe the polytene chromosomes. From these smears the corresponding karyotype of each larva was determined, keeping a record of them. With the information gathered the relative frequency of each one of the fourteen different inversions found was calculated. A grand total of 1894 third chromosomes were analyzed. The fourteen different inversions found are equivalent to a 34.1 % of the total chromosomal variation of the species. The most abundant inversions found were: TL 50.6 %, CU 27.2 5, SC 9.1 % and EP 5.5 %; the remaining ten inversions detected are in general grounds rare ones with variable relative frequencies depending on the locality. Analysis of the predominant inversions for each population was done. The presence of West-East gradients is reported, even if in cases not so well defined, since as one moves in a particular direction the ups and downs in relative frequency for the alternating pairs TL-CU; TL-SC in the western populations and TL-CU in the eastern ones were observed. The assignment of each population to a particular race was also done, and such a way we were able to recognize three different races coexisting in the area of study.


Genetika ◽  
2006 ◽  
Vol 38 (2) ◽  
pp. 97-105 ◽  
Author(s):  
Víctor Salceda ◽  
José Espinoza-Velazquez

Chromosomal polymorphism for the third chromosome in Drosophila pseudoobscura has been widely studied for genetic variation in different environments or locations far apart. However, there is less information regarding sites geographically near one another. Targeting on possible micro-geographic variation in the species, a serial study was done on 12 Mexican populations grouped in four regions, including locations in Durango (DU), the border area of Guanajuato-San Luis Potosi states (GP), Chiapas (CH) and Saldilo (SA). Flies were trapped in their natural habitats using fermenting bananas as bait. They were individually cultivated in the laboratory for larvae production. In a given population sample several flies were cultivated together but only one larva per culture provided salivary tissue to observe polytene chromosomes. Gene arrangements or inversions were identified and frequencies were calculated. A total of 767 third chromosomes were studied and 11 different inversions detected. The type and relative frequencies of the arrangements varied among regions. From the 11 inversions observed, 10 were found in Durango, five in Guanajuato-San Luis Potosi and Chiapas, and eight in Saltillo. The inversion frequencies in the Durango locations varied in four cases, but only one in Chiapas, three cases in Guanajuato-San Luis Potosi, and five in Saltillo. It was also observed that there were geographical gradients for inversions within regions as follows: four arrangements in Saltillo and Durango, three in Guanajuato-San Luis Potos? and one in Chiapas. Moreover, all four regions studied showed evidences for micro-geographical variation. Nevertheless, more studies are needed to elucidate the relevance of the inversion frequencies changes in neighboring populations and also any seasonal-annual frequencies observed in the locations studied here.


1959 ◽  
Vol 37 (4) ◽  
pp. 571-589 ◽  
Author(s):  
V. R. Basrur ◽  
K. H. Rothfels

Populations of Cnephia mutata in southern Ontario contain both diploid and triploid individuals. The diploid form is bisexual and lacks chromosomal polymorphism except for a rearrangement involved in its cytological sex determining mechanism. The triploids are parthenogenetic; they produce female progeny only and are highly heterozygous for inversions. The banding pattern of the salivary gland chromosomes of diploids and triploids is very similar; the identical standard sequence occurs in both. The complete lack of autosomal inversions in diploids contrasted with their abundance in triploids indicates that effective genetic exchange does not occur between the two forms; they are reproductively completely isolated, although opportunity for cross-mating would seem to exist. The origin of polyploid parthenogenetic forms in black flies is discussed and the view is favored that they are autopolyploid and automictic.


Genome ◽  
1999 ◽  
Vol 42 (1) ◽  
pp. 80-86 ◽  
Author(s):  
Chaliow Kuvangkadilok ◽  
Suwannee Phayuhasena ◽  
Visut Baimai

A standard photographic map of Simulium feuerborni (Diptera: Simuliidae) was constructed from larval salivary gland polytene chromosomes and is described herein. Analysis of polytene chromosomes was made from wild larvae collected from the four populations at Doi Inthanon National Park, Chiang Mai Province, northern Thailand. Simulium feuerborni has three pairs of chromosomes (2n = 6) which are arranged from the longest to the shortest. Chromosome I is metacentric while chromosomes II and III are submetacentric. A total of six simple paracentric inversions have been detected in these natural populations of S. feuerborni. These inversions (IS-1, IL-1, IIL-1, IIL-2, IIIS-1, IIIL-1) occurred in all chromosome arms except for the arm IIS. Significant deviation from Hardy-Weinberg equilibrium has been observed in inversion IIIL-1 at Hui Sai Luaeng suggesting the existence of two gene pools in this population. There is no indication of sex linkage associated with an inversion sequence in these populations. Thus, the X and Y chromosomes of S. feuerborni could not be recognized in this study.Key words: Simulium, polytene chromosome map, inversion polymorphisms


Genome ◽  
1995 ◽  
Vol 38 (3) ◽  
pp. 426-434 ◽  
Author(s):  
Anan Poopittayasataporn ◽  
Visut Baimai

Photographic maps and rearrangements of each salivary gland polytene chromosome arm of Anopheles nemophilous (species F) and of An. dirus species A, B, C, and D of the Dirus group from natural populations in Thailand are presented. Structural conformation of heterokaryotypes and comparison of chromosome banding sequences reveal 10 paracentric inversions. The data on fixed inversion of 3Rb and inversion polymorphism of the X chromosome shared by these species were used to construct a phylogeny of the five members of the An. dirus complex, thereby outlining their patterns of speciation through chromosomal rearrangements.Key words: polytene chromosome rearrangements, Anopheles dirus, phylogeny.


1998 ◽  
Vol 76 (2) ◽  
pp. 361-376
Author(s):  
Iya I Kiknadze ◽  
Malcolm G Butler ◽  
Karlygash G Aimanova ◽  
Evgenya N Andreeva ◽  
Jon Martin ◽  
...  

Chromosomal polymorphism is described for natural populations of Chironomus pallidivittatus in both the Palearctic and Nearctic regions. The Palearctic populations studied exhibit 24 banding sequences, whereas 10 banding sequences have been recorded from Nearctic C. pallidivittatus. In total, 29 sequences and 37 genotypic combinations have been found. Of the 29 sequences known, only 5 are Holarctic (common to both the Nearctic and Palearctic), 19 are exclusively Palearctic, and 5 are Nearctic. The karyotype of Nearctic C. pallidivittatus is characterized by specific, homozygous Nearctic sequences in arms B and G and fixed Holarctic inversion sequences in the other arms. Only two chromosome arms in C. pallidivittatus, but all seven arms in the sibling species Chironomus tentans, differ between Palearctic and Nearctic forms by the presence of unique, homozygous sequences in the Nearctic karyotype. This indicates a great difference in the cytogenetic histories of these closely related species; much less karyotypic divergence between continents has occurred in C. pallidivittatus than in C. tentans. The cytogenetic distance between Palearctic and Nearctic populations of C. tentans is higher (DN = 1.62) than in C. pallidivittatus (DN = 0.27). Thus, Palearctic and Nearctic C. tentans should be regarded as sibling species, but Palearctic and NearcticC. pallidivittatus are best viewed as strongly divergent races of the same species. A photomap of polytene chromosomes of C. pallidivittatus is presented in which banding sequences are mapped by using C. tentans as a standard.


Genetika ◽  
2010 ◽  
Vol 42 (1) ◽  
pp. 67-78
Author(s):  
Víctor Salceda ◽  
Judith Guzmán

Chromosomal polymorphism in natural populations of Drosophila pseudoobscura have been broadly studied in the USA but scarcely in Mexico where only about 60 localities have been analyzed. Differences among both regions are notorious with respect to their chromosomal constitution. Northern populations, those of USA, have as representative inversions the sequences ST, AR and CH contrasting with those in Southern populations (Mexico) in which prevail the gene arrangements TL, CU and SC. Assuming as a probable mechanism that has allowed these substitutions the flow generated by the presence of a North - South clines, we took as a goal find out if such clines really exist. With that objective in mind we studied 29 populations of this species distributed along four North - South transects. Specimens of D. pseudoobscura caught by attracting them with fermenting bananas were carried to the laboratory where from each female an isofemale line was established. When their offspring appeared a single larva from each isofemale was taken, its salivary glands extracted and stained with a solution of lacto- aceto- orcein, by these means the polytene chromosomes were obtained. On these chromosomes we identified, for each larva, the inversion (s) carried in the third chromosome, in such a way 3439 third chromosomes were analyzed. Among the 29 localities we identified 17 different inversions but the number of them varied from population to population from three to eleven. Relative frequencies of each inversion at every location were calculated and with them for each transect the presence or absence of clines was determined. Among each transect the existence of clines was observed only between two or three near by populations, but we were not able to find a clear manifestation of the presence of clines along a complete transect. Our results at this respect are similar to those previously reported for USA populations. A mechanism that explains North - South substitutions of predominant inversions remains as open question.


2016 ◽  
Vol 14 (4) ◽  
pp. 41 ◽  
Author(s):  
Natalia V Vinokurova ◽  
Evgeniya A Kalinina ◽  
Edgar E Stol’

Background. A larvae of family Chironomidae are the most mass and widespread species of macrozoobenthos and play an important role in the lives of almost all types of reservoirs. They constitute a convenient model in the analysis of anthropogenic influences. Besides, chironomids have the largest polytene chromosomes in nature that allow carrying out cytogenetic analysis of the impact of various toxic substances on chromosomal aberrations. Materials and methods. The karyotype and chromosomal inversion polymorphism one of the species phytophilic chironomids Glyptotendipes glaucus (Meigen, 1818) from five reservoirs of Kaliningrad (ponds Chistyi and Mel’nichnyi, system of ponds Karasevka, lakes Pen’kovoe and Shkol’noe) was studied. Cytological mapping of chromosomes was performed by system of Belyanina and Durnova (1998). Results. The levels of natural inversion polymorphism for each populations were determined. Comparison of inversion polymorphism with early data for Saratov, Bryansk and Kaliningrad regions was carried. The preservation of tendencies of distribution and prevalence gomo-and heterozygotic inversions of glaB1.2, glaB2.2 and also consolidation in the karyofund of populations sequence glaA2 in the heterozygous state in ponds Karasevka and Chistyi was observed. The characteristic for an earlier research of populations Glyptotendipes glaucus of Kaliningrad the presence inversion sequences glaG4 and glaD2 is retained. The level of inversion polymorphism for reservoirs of Kaliningrad has decreased and has approached nearer to data for Bryansk and Saratov regions. Conclusion. Based on these results we can offer a working hypothesis of a direct dependence of value of chromosomal polymorphism on the level of pollution of reservoirs ions of heavy metals (Kaliningrad), long-living radionuclides (Bryansk region), nitrates and ions of ammoniac nitrogen (Saratov region).


Genetika ◽  
2009 ◽  
Vol 41 (2) ◽  
pp. 155-167
Author(s):  
Víctor Salceda

Chromosomal polymorphism in natural populations of Drosophila pseudoobscura have been broadly studied in the USA but scarcely in Mexico where only about 60 localities have been analyzed. Differences among both regions are notorious with respect to their chromosomal constitution. Northern populations, those of USA, have as representative inversions the sequences ST, AR and CH contrasting with those in Southern populations (Mexico) in which prevail the gene arrangements TL, CU and SC. Assuming as a probable mechanism that has allowed these substitutions the flow generated by the presence of a North - South clines, we took as a goal find out if such clines really exist. With that objective in mind we studied 29 populations of this species distributed along four North - South transects. Specimens of D. pseudoobscura caught by attracting them with fermenting bananas were carried to the laboratory where from each female an isofemale line was established. When their offspring appeared a single larva from each isofemale was taken, its salivary glands extracted and stained with a solution of lacto-aceto- orcein, by these means the polytene chromosomes were obtained. On these chromosomes we identified, for each larva, the inversion (s) carried in the third chromosome, in such a way 3439 third chromosomes were analyzed. Among the 29 localities we identified 17 different inversions but the number of them varied from population to population from three to eleven. Relative frequencies of each inversion at every location were calculated and with them for each transect the presence or absence of clines was determined. Among each transect the existence of clines was observed only between two or three near by populations, but we were not able to find a clear manifestation of the presence of clines along a complete transect. Our results at this respect are similar to those previously reported for USA populations. A mechanism that explains North - South substitutions of predominant inversions remains as open question.


Genetics ◽  
1983 ◽  
Vol 103 (3) ◽  
pp. 465-482
Author(s):  
Hampton L Carson

ABSTRACT Of 103 picture-winged Drosophila species endemic to the high Hawaiian islands, all but three are endemic to single islands or island complexes. They are presumed to have evolved in situ on each island. The banding pattern sequences of the five major polytene chromosomes of these species have been mapped to a single set of Standard sequences. Sequential variation among these chromosomes is due to 213 paracentric inversions. An atlas of their break points is provided. Geographical, morphological and behavioral data may be used to supplement the cytological information in tracing ancestry. Starting at the newer end of the archipelago, the 26 species of the Island of Hawaii (less than 700,000 years old) are inferred to have been derived from 19 founders, 15 from the Maui complex, three from Oahu and one from Kauai. The existence of 40 Maui complex species is explicable as resulting from 12 founders, ten from Oahu and two from Kauai. The 29 Oahu species can be explained by 12 founder events, five from Kauai and seven from Maui complex (summary in Figure 5). Although the ancestry of two Kauai species can be traced to newer islands, the ten remaining ones on this island (age about 5.6 million years) are apparently ancient elements in the fauna, relating ultimately to Palearctic continental sources.


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