Cytological studies of sibling species of Simulium tuberosum (Lundström) (Diptera: Simuliidae)

1982 ◽  
Vol 60 (3) ◽  
pp. 292-303 ◽  
Author(s):  
G. F. Mason
Keyword(s):  
Y Chromosome ◽  
Geographic Distribution ◽  
Sibling Species ◽  
Common Ancestor ◽  
Polytene Chromosomes ◽  
Chromosome Arm ◽  
Chromosome Pattern ◽  
High Degree

This paper extends the known geographic distribution of S. tuberosum siblings recorded in 1962 by R. Landau by analyzing the polytene chromosomes in the larva. Her seven basic IIS arrangements are augmented by the addition of four new types. These were St/A, A/A; CDE-2/CDE, CDE/CDE; Y2/AB, AB/AB; and FGI. These new siblings, like the originals, have fixed differences in chromosome arm IIS. One of these, FGI, distinguished by a high degree of polymorphism, and the presence of fixed differences from the tuberosum standard in arms IS, IL, and IIIL, occurred both in Alaska and Norway. A comparison of the standard tuberosum, the S. venustum, and the FGI sibling chromosome pattern revealed the FGI sibling to be much closer to the venustum standard than any other tuberosum sibling. A second new sibling (Y2/AB) from Norway differed from the standard in the Y chromosome by multiple rearrangements in IIS and two tandem inversions in IIL. The fixed changes on arms other than IIS in the FGI siblings and the Y2/AB sibling are the first to be detected in this complex. There were a number of shared inversions in the populations studied indicating a common ancestor and (or) introgression.

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.

scholarly journals Genetics of sexual isolation in male hybrids of Drosophila simulans and D. mauritiana

1996 ◽  
Vol 68 (3) ◽  
pp. 211-220 ◽  
Author(s):  
Jerry A. Coyne
Keyword(s):  
Genetic Analysis ◽  
Y Chromosome ◽  
Sibling Species ◽  
Previous Analysis ◽  
Sexual Isolation ◽  
Drosophila Simulans

SummarySexual isolation between the sibling species D. simulans and D. mauritiana is due largely to the rejection of D. simulans males by D. mauritiana females. Genetic analysis shows that genes on the X and third chromosomes contribute to the differences between males causing sexual isolation, while the Y chromosome, second chromosome and cytoplasm have no effect. These chromosome effects differ from those observed in a previous analysis of sexual isolation in hybrid females, implying that different genes cause sexual isolation in the two sexes.

Cytogenetic characterization of a genetic sexing strain in Ceratitis capitata

Genome ◽  
1991 ◽  
Vol 34 (4) ◽  
pp. 606-611 ◽  
Author(s):  
A. Zacharopoulou ◽  
M. E. Riva ◽  
A. Malacrida ◽  
G. Gasperi
Keyword(s):  
Y Chromosome ◽  
Ceratitis Capitata ◽  
Chromosomal Rearrangements ◽  
Polytene Chromosomes ◽  
Chromosome 2 ◽  
Genetic Sexing ◽  
Cytogenetic Characterization ◽  
Cytological Characteristics ◽  
Genetic Sexing Strain

A genetic sexing strain of Ceratitis capitata, carrying a null mutation for ADH activity linked to the Y chromosome, was analysed cytogenetically. In addition to an insertion of a large part of the Y chromosome into chromosome 2, this strain carries two other chromosomal rearrangements, a deletion in the second chromosome and a reciprocal translocation involving chromosomes 2 and 4. The progeny of the T(2;4) translocation heterozygote with unbalanced chromosome constitution can survive up to the larval and (or) to the adult stage. These cytological characteristics are discussed in relation to the genetic sexing behaviour of this line.Key words: Ceratitis capitata, polytene chromosomes, genetic sexing.

scholarly journals Evolutionary plasticity of mating-type determination mechanisms in Paramecium aurelia sibling species

2020 ◽  
Author(s):  
Natalia Sawka-Gądek ◽  
Alexey Potekhin ◽  
Deepankar Pratap Singh ◽  
Inessa Grevtseva ◽  
Olivier Arnaiz ◽  
...  
Keyword(s):  
Mating Type ◽  
Sibling Species ◽  
Common Ancestor ◽  
Genome Duplication ◽  
Transmembrane Protein ◽  
Type Systems ◽  
Regulation Mechanism ◽  
Additional Species ◽  
Evolutionary Transitions ◽  
Genetic Determination

Abstract The Paramecium aurelia complex, a group of morphologically similar but sexually incompatible sibling species, is a unique example of the evolutionary plasticity of mating-type systems. Each species has two mating types, O (Odd) and E (Even). Although O and E types are homologous in all species, three different modes of determination and inheritance have been described: genetic determination by Mendelian alleles, stochastic developmental determination, and maternally inherited developmental determination. Previous work in three species of the latter kind have revealed the key roles of the E-specific transmembrane protein mtA and its highly specific transcription factor mtB: type O clones are produced by maternally inherited genome rearrangements that inactivate either mtA or mtB during development. Here we show, through transcriptome analyses in 5 additional species representing the three determination systems, that mtA expression specifies type E in all cases. We further show that the Mendelian system depends on functional and non-functional mtA alleles, and identify novel developmental rearrangements in mtA and mtB which now explain all cases of maternally inherited mating-type determination. Epistasis between these genes likely evolved from less specific interactions between paralogs in the P. aurelia common ancestor, after a whole-genome duplication, but the mtB gene was subsequently lost in three P. aurelia species which appear to have returned to an ancestral regulation mechanism. These results suggest a model accounting for evolutionary transitions between determination systems, and highlight the diversity of molecular solutions explored among sibling species to maintain an essential mating-type polymorphism in cell populations.

scholarly journals Description of two new species of Stigmaeopsis, Banks 1917 (Acari, Tetranychidae) inhabiting Miscanthus grasses (Poaceae)

Acarologia ◽  
2018 ◽  
Vol 58 (2) ◽  
pp. 414-429
Author(s):  
Y. Saito ◽  
Y. Sato ◽  
A.R. Chittenden ◽  
J.-Z. Lin ◽  
Y.-X. Zhang
Keyword(s):  
New Species ◽  
Geographic Distribution ◽  
Sibling Species ◽  
Genetic Data ◽  
The Other ◽  
Male Aggression ◽  
Japanese Species ◽  
Two New Species ◽  
New Diagnosis ◽  
Japan And China

We provided a new diagnosis of the genus Stigmaeopsis. Then we described two new species that are very closely related to Stigmaeopsis miscanthi (Saito) from Miscanthus spp. in Japan and China. The Japanese species, named Stigmaeopsis sabelisi Saito and Sato n. sp., was previously referred to as Stigmaeopsis miscanthi low aggressiveness form , and is characterized by its low male-to-male aggression behavior. The other species, Stigmaeopsis continentalis Saito and Lin n. sp., was found in China (Fujian district). Thus four species could be discriminated from the species inhabiting Miscanthus and reed grasses. However, the two new species and S. miscanthi resemble each other very closely, thus they are considered to be sibling species. To identify them several naive characters, geographic distribution and genetic data are needed. An updated key to all known species of Stigmaeopsis is also proposed.

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.

Nonrandom distribution of long mono- and dinucleotide repeats in Drosophila chromosomes: correlations with dosage compensation, heterochromatin, and recombination

1989 ◽  
Vol 9 (3) ◽  
pp. 1173-1182
Author(s):  
K Lowenhaupt ◽  
A Rich ◽  
M L Pardue
Keyword(s):  
Y Chromosome ◽  
Dna Sequences ◽  
Polytene Chromosomes ◽  
Drosophila Species ◽  
Repeated Dna ◽  
Dinucleotide Repeats ◽  
Order Of Magnitude ◽  
The Individual ◽  
And Function

Long stretches of (dC-dA)n.(dT-dG)n, abbreviated CA/TG, have a distinctive distribution on Drosophila chromosomes (M.L. Pardue, K. Lowenhaupt, A. Rich, and A. Nordheim, EMBO J. 6:1781-1789, 1987). The distribution of CA/TG suggests a correlation with the overall transcriptional activity of chromosomal regions and with the ability to undergo meiotic recombination. These correlations are conserved among Drosophila species and may indicate one or more chromosomal functions. To test the generality of these findings, we analyzed the distribution of the rest of the six possible mono- and dinucleotide repeats (A/T, C/G, AT/AT, CA/TG, CT/AG, and CG/CG). All but CG/CG were present at significant levels in the genomes of the six Drosophila species studied; however, A/T levels were an order of magnitude lower than those of the other sequences. Data base analyses suggested that the same sequences are present in other eucaryotes. Like CA/TG, both CT/AG and C/G showed increased levels on dosage-compensating chromosomes; however, the individual sites clearly differed for each sequence. In contrast, A/T and AT/AT, although present in Drosophila DNA, could not be detected in situ in polytene chromosomes. We also used in situ hybridization to analyze the neo-Y chromosome of Drosophila miranda, an ancestral autosome that has become attached to the Y chromosome and is now partially heterochromatic. The neo-Y has acquired repeated DNA sequences; we found that the added sequences are as devoid of mono- and dinucleotide repeats as other heterochromatin. The distribution and function of these sequences are likely to result from both their repetitious nature and base contents.

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.

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