Cytotaxonomy of Simulium (Montisimulium) ghoomense (Diptera: Simuliidae) from the Darjeeling Hills, India

Zootaxa ◽  
2011 ◽  
Vol 2872 (1) ◽  
pp. 49
Author(s):  
WILLIE HENRY ◽  
SACHIN THAPA ◽  
PETER H. ADLER ◽  
SUBRATA KUMAR DEY ◽  
RAKESH VARMA
Keyword(s):  
Sibling Species ◽  
Sex Chromosomes ◽  
Polytene Chromosomes ◽  
Haploid Number ◽  
Total Complement ◽  
Chromosomal Map

The polytene chromosomes are mapped for a scarce Himalayan simuliid, Simulium (Montisimulium) ghoomense Datta, from the Darjeeling area of India. This species has three tightly paired polytene chromosomes with a haploid number of 3. Chromosomes I, II, and III account for 39.6%, 30.3%, and 30.1% of the total complement length, respectively. The centromeres of chromosomes II and III consistently form a putative partial chromocenter. Sex chromosomes are undifferentiated and polymorphisms and sibling species are lacking in a sample of 35 larvae. This is the first chromosomal map for a species in the subgenus Montisimulium in India.

Sibling species and sex chromosomes in Eusimulium vernum (Diptera: Simuliidae)

1985 ◽  
Vol 63 (9) ◽  
pp. 2145-2161 ◽  
Author(s):  
C. Brockhouse
Keyword(s):  
Sex Determination ◽  
Sibling Species ◽  
Sex Chromosomes ◽  
Polytene Chromosomes ◽  
Biological Species ◽  
Undescribed Species ◽  
Ecological Segregation ◽  
Sex Locus

The polytene chromosomes of larvae from samples of Eusimulium vernum, E. bicorne, and an undescribed species (designated here as Eusimulium "Yukon") were examined. Twelve cytotypes within E. vernum were distinguished, of which at least eight appear to be good biological species. These cytotypes, together with the two allied morphospecies, were related in a cytophylogeny. An ecological segregation between some of the siblings was observed. One cytotype apparently utilizes two (possibly three) separate chromosome (arms) in sex determination. Five of the total of six chromosome arms are involved in sex determination in the various members of this complex. The genetics of sex determination and the mechanisms of sex-locus shift are discussed in the context of these findings.

Polytene chromosomes of three species of blackflies in the Simulium pictipes group (Diptera: Simuliidae)

1975 ◽  
Vol 53 (8) ◽  
pp. 1147-1164 ◽  
Author(s):  
Daniel G. Bedo
Keyword(s):  
Salivary Gland ◽  
Chromosome Number ◽  
Sibling Species ◽  
Sex Chromosomes ◽  
Polytene Chromosomes ◽  
Fluorescence Staining ◽  
Haploid Chromosome Number ◽  
Quinacrine Fluorescence ◽  
Individual Bands ◽  
Staining Methods

The salivary gland chromosomes of members of the Simulium pictipes group were examined by conventional staining and quinacrine fluorescence staining methods which proved to be a useful tool to show otherwise hidden details, especially in expanded centromere regions. Three cytologically definable species were found, one of which must represent a previously unrecognized species. Simulium longistylatum Shewell was the only species among the three siblings identified with certainty. The remaining pair were designated as S. pictipes A and S. pictipes B. In all three siblings the haploid chromosome number was three. Specific differences include a simple and a complex inversion, a shift of basal bands between the short arms of the second and third chromosome, details of the sex chromosomes, and the amount of DNA in certain individual bands and expanded centromere regions. Y chromosome markers are located in a different element of the complement in each of the three species, a unique situation within closely related blackfly sibling species. These findings are discussed in connection with the evolution of sex chromosomes and sibling species. A cytophylogeny is presented.

Genetic and cytogenetic analysis of the fruit fly Rhagoletis cerasi (Diptera: Tephritidae)

Genome ◽  
2008 ◽  
Vol 51 (7) ◽  
pp. 479-491 ◽  
Author(s):  
Ilias Kounatidis ◽  
Nikolaos Papadopoulos ◽  
Kostas Bourtzis ◽  
Penelope Mavragani-Tsipidou
Keyword(s):  
Salivary Gland ◽  
Sex Chromosomes ◽  
Cytogenetic Analysis ◽  
Polytene Chromosomes ◽  
Fruit Fly ◽  
Pest Species ◽  
Heteromorphic Sex Chromosomes ◽  
Weak Points ◽  
Heterogametic Sex ◽  
Rhagoletis Cerasi

The European cherry fruit fly, Rhagoletis cerasi , is a major agricultural pest for which biological, genetic, and cytogenetic information is limited. We report here a cytogenetic analysis of 4 natural Greek populations of R. cerasi, all of them infected with the endosymbiotic bacterium Wolbachia pipientis . The mitotic karyotype and detailed photographic maps of the salivary gland polytene chromosomes of this pest species are presented here. The mitotic metaphase complement consists of 6 pairs of chromosomes, including one pair of heteromorphic sex chromosomes, with the male being the heterogametic sex. The analysis of the salivary gland polytene complement has shown a total of 5 long chromosomes (10 polytene arms) that correspond to the 5 autosomes of the mitotic nuclei and a heterochromatic mass corresponding to the sex chromosomes. The most prominent landmarks of each polytene chromosome, the “weak points”, and the unusual asynapsis of homologous pairs of polytene chromosomes at certain regions of the polytene elements are also presented and discussed.

CYTOTAXONOMY OF BOMBYLIIDAE (DIPTERA)

1973 ◽  
Vol 15 (1) ◽  
pp. 21-37 ◽  
Author(s):  
J. W. Boyes ◽  
G. E. Shewell
Keyword(s):  
Sex Chromosomes ◽  
Chromosome Numbers ◽  
Total Complement ◽  
Variable Group

The karyotypes of 34 species of Bombyliidae are described, some in greater detail than others. It is suggested that two subfamilies, the Bombyliinae (for Homoeophthalmae) and Anthracinae (for Tomophthalmae) be recognized. In the Bombyliinae, one species has 2n = 8, one 2n = 10, three 2n = 12 and one 2n = 14. In the Anthracinae, two species have 2n = 10, four 2n = 12, six 2n = 14, three 2n = 16 and thirteen 2n = 18. Seventeen complements of Bombyliinae averaged 41.4 μ in total complement length (TCL) and thirtyeight of Anthracinae averaged 46.6 μ; so the 55 complements of the Bombyliidae averaged 44.9 μ in TCL, the complements with lower chromosome numbers averaging less than those with higher numbers. Thus Bombyliinae species have lower chromosome numbers and shorter complements than Anthracinae species which tend to have longer metacentric sex chromosomes. Thus both morphologically and karyotypically the Bombyliinae appear to be more advanced whereas the Anthracinae are a more primitive but highly variable group of species.

Sibling species and sex chromosome differentiation in Simulium neornatipes (Diptera: Simuliidae)

1984 ◽  
Vol 26 (3) ◽  
pp. 318-325 ◽  
Author(s):  
D. G. Bedo
Keyword(s):  
Polytene Chromosome ◽  
Sibling Species ◽  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Close Association ◽  
Chromosome Analysis ◽  
Sex Linkage ◽  
Direct Role ◽  
Chromosome Differentiation ◽  
Close Relationship

Polytene chromosome analysis of five Simulium neornatipes populations not only confirms the existence of the two sibling species, S. neornatipes 1 and 2, proposed earlier but reveals a third. S. neornatipes 3. These sibling species share a common standard polytene chromosome banding sequence which differs from the Australian S. ornatipes complex standard by five fixed inversions. The sharing of polymorphic inversions between the ornatipes and neornatipes complexes indicates their close relationship. The neornatipes species are distinguished from each other by additional fixed inversions and differentiated sex chromosomes. Extensive sex chromosome differentiation involving chromosome III has occurred in S. neornatipes 1 and 2. A period of incomplete sex-linkage allowing reassortment of inversions must have preceded the currently observed strong sex-linkage of differentiated sex chromosomes to account for the complex array of sex chromosomes found. The close association of sex chromosome differentiation with speciation in black flies is discussed in relation to appropriate speciation mechanisms. It is concluded that the rearrangements themselves have no direct role in the speciation process.Key words: sibling species, sex chromosomes, Simuliidae.

Sibling species of the blackfly Prosimulium onychodactylum (Simuliidae, Diptera): a salivary gland chromosome study

1983 ◽  
Vol 61 (12) ◽  
pp. 2816-2835 ◽  
Author(s):  
Lester J. Newman
Keyword(s):  
Salivary Gland ◽  
Reproductive Isolation ◽  
Sibling Species ◽  
Chromosome Pairing ◽  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Homologous Pairing ◽  
Chromosome Markers ◽  
Chromosome Arm ◽  
Backcross Hybrids

Larvae of the morphospecies Prosimulium onychodactylum collected from two streams in northern Oregon are divided into 11 sibling species based on fixed and polymorphic inversions. The sibling species have differentiated sex chromosomes; each sibling species falls into one of two groups based on the chromosome arm which carries the sex chromosome markers. Males exhibit lack of homologous pairing or inversion heterzygosity and females have complete chromosome pairing or inversion homozygosity. There is a succession of sibling species which mature in the streams from January through September. Mature larvae of each sibling species are present for about 6 weeks; some are synchronic while others are allochronic. Some of the sibling species occur in the same stream and others are in different streams. Sibling species which are both synchronic and sympatric appear to be reproductively isolated. Reproductive isolation may not be complete for sibling species which are normally allopatric or allochronic; small numbers of F1 and backcross hybrids were found between some of these sibling species. The division of the morphospecies into sibling species was also observed in collections from Washington through northern California.

scholarly journals Polytene chromosomes of an Indian Himalayan black fly Simulium (Nevermannia) praelargum (Diptera: Simuliidae)

2010 ◽  
Vol 56 (4) ◽  
pp. 437-444 ◽  
Author(s):  
Willie Henry ◽  
Subrata Kumar Dey ◽  
Rakesh Varma ◽  
Sachin Thapa ◽  
William S Procunier
Keyword(s):  
High Resolution ◽  
Polytene Chromosome ◽  
Polytene Chromosomes ◽  
Nucleolar Organizer ◽  
Metacentric Chromosome ◽  
Double Bubble ◽  
High Quality ◽  
Chromosomal Markers ◽  
Total Complement ◽  
Chromosome Maps

Abstract High quality polytene chromosome maps (n=3) of a Himalayan Simuliid Simulium praelargum Datta, 1973 are presented and represent the first cytological description of a taxon found in the feuerborni group, subgenus Nevermannia. Polytene chromosomes one (I) and two (II) are metacentric, chromosome three (III) is submetacentric with the length of each chromosome occupying 37.25 %, 31.36 % and 31.34 % of the total complement length, respectively. Typical simuliid diagnostic intergeneric chromosomal markers are found within the polytene complement of this species. The nucleolar organizer (N.O.) is found at the base of the short arm of chromosome one (IS), the Ring of Balbiani (R.B.), double bubble (D.B.) and triad occur in the short arm of chromosome two (IIS), the Parabalbiani Ring (P.B.) and grey band (gb) occur in the long arm of chromosome two (IIL) and the Blister (BL) and Capsule (Ca) occur in the short arm of chromosome three (IIIS).Terminal bands at the end of IIIS are heterochromatinized and present atypically with respect to other simuliid fauna. Populations studied so far are unique among the Simuliidae in that they exhibit chromosome structural monomorphism. These high resolution polytene chromosome maps will form the basis for future cytological characterization and phylogenetic comparisons amongst members of the feuerborni group.

SOMATIC METAPHASE CHROMOSOMES IN GEOGRAPHIC ISOLATES OF THE CARROT RUST FLY, CHAMAEPSILA ROSAE (F.) (DIPTERA: PSILIDAE)

1957 ◽  
Vol 35 (3) ◽  
pp. 453-458 ◽  
Author(s):  
J. G. Robertson
Keyword(s):  
Chromosome Number ◽  
Comparative Study ◽  
X Chromosome ◽  
Sex Chromosomes ◽  
Prince Edward Island ◽  
Metaphase Chromosomes ◽  
Somatic Metaphase ◽  
Total Length ◽  
Total Complement ◽  
Secondary Constrictions

A comparative study of somatic metaphase complements of the carrot rust fly, Chamaepsila rosae (F.), from England, Prince Edward Island, Ontario, and British Columbia showed that the chromosome number is eight and that all chromosomes are metacentric. The means of the total complement length ranged from 50.8 to 53.5 and the lengths for chromosomal pairs I–IV averaged 36.5, 24.8, 22.3, and 16.5% of the total length respectively for the four regions. The sex chromosomes are the largest elements in the complement, the X chromosome being 36.5% of the total length and the Y 28.8%. The arm ratios for members X, Y, II, III, and IV are 1.34, 1.13, 1.57, 1.21, and 1.34 respectively. Secondary constrictions were both infrequent and irregular in location. The work emphasizes that much caution is necessary in analyzing metaphase chromosomes for taxonomic purposes.

The polytene chromosomes of Drosophila triauraria and D. quadraria, sibling species of D. auraria

Genome ◽  
1992 ◽  
Vol 35 (2) ◽  
pp. 318-326 ◽  
Author(s):  
P. Mavragani-Tsipidou ◽  
Z. G. Scouras ◽  
K. Haralampidis ◽  
S. Lavrentiadou ◽  
C. D. Kastritsis
Keyword(s):  
Sibling Species ◽  
Polytene Chromosomes ◽  
Chromosome Arm ◽  
Paired Condition ◽  
Homozygous Strain ◽  
Paracentric Inversions ◽  
Mode Of Inheritance ◽  
Tandem Duplications

The polytene chromosomes of Drosophila triauraria and D. quadraria, two of the sibling species of D. auraria, were examined. The polytene chromosomes of all three species exhibit very clear homology. Unlike the stock of D. auraria that we studied, D. triauraria and D. quadraria carry heterozygous paracentric inversions. In both species, 2R and 3R are the arms where these inversions are concentrated. In addition, in D. quadraria, the 3L chromosome arm is very complicated because of heterozygous inversions. The mode of inheritance of these rearrangements was studied. A homozygous strain for all chromosome arms of D. triauraria was isolated, while a homozygous strain was obtained only for the arms X, 2L, 3L, and 4 of D. quadraria. Like D. auraria, both species show a large number of inverted tandem duplications in the paired condition, even in the chromosomes of their hybrids. Small deletions were also detected, one of which, in D. triauraria, is homozygous terminal. Hypotheses are discussed concerning the relationships of the species and the existence of inverted tandem duplications.Key words: Drosophila, duplications, inversions, deletions, evolution.

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