Divergent cytogenetic evolution in Nearctic and Palearctic populations of sibling species in Chironomus (Camptochironomus) Kieffer

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.

Genome ◽  
1989 ◽  
Vol 32 (4) ◽  
pp. 516-521 ◽  
Author(s):  
Charles Brockhouse ◽  
J. A. B. Bass ◽  
R. M. Feraday ◽  
N. A. Straus

B chromosomes are present in a cluster of closely related species of black fly in the Simulium vernum group including six sibling species within the S. vernum complex, Simulium costatum, and Simulium juxtacrenobium. The S. vernum siblings all possess the same small metacentric supernumerary, while S. juxtacrenobium carries three different supernumeraries (two telocentrics and one metacentric) and S. costatum has both a metacentric and a telocentric B chromosome. Analysis of the polytene chromosomes in the larval salivary glands has revealed relationships between the supernumeraries of the different species. The metacentric B chromosome of the S. vernum siblings apparently results from a fusion of the two telocentric supernumeraries of S. juxtacrenobium. Acquisition of a nucleolar organizer then gave rise to the metacentric B chromosome in S. juxtacrenobium. The acquisition of a nucleolus by a S. juxtacrenobium telocentric gave rise to one of the S. costatum supernumeraries. Two alternate models for the origin of black fly supernumeraries are presented.Key words: supernumerary chromosome, black fly, polytene chromosome, chromosome evolution.


Phytotaxa ◽  
2015 ◽  
Vol 217 (2) ◽  
pp. 164 ◽  
Author(s):  
İlker Çinbilgel ◽  
özkan Eren ◽  
Hayri Duman ◽  
Mustafa Gökceoğlu

Pimpinella ibradiensis, an unusual new species found in the Toka Yayla (İbradı, Antalya) in southern Anatolia, is described and illustrated. Site conditions, synecology and conservation status of P. ibradiensis are considered. In light of the comparison with the other closely related four species, namely P. nephrophylla, P. flabellifolia, P. sintenisii and P. paucidentata, its similarity within the genus are discussed. P. ibradiensis is easly distinguished from its relatives by its white petals, presence of bracts and bracteoles, larger fruits (4–5.5 × 1–2 mm), and having serrulate basal leaves with 60–95 strongly cartilaginous teeth along margins. The geographical distribution of P. ibradiensis and closely related species are mapped and the identification key of those species is updated.


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.


2019 ◽  
Author(s):  
Andrea Acurio ◽  
Flor T. Rhebergen ◽  
Sarah Paulus ◽  
Virginie Courtier-Orgogozo ◽  
Michael Lang

AbstractBackgroundMale genitals have repeatedly evolved left-right asymmetries, and the causes of such evolution remain unclear. TheDrosophila nannopteragroup contains four species, among which three exhibit left-right asymmetries of distinct genital organs. In the most studied species,Drosophila pachea, males display asymmetric genital lobes and they mate right-sided on top of the female. Copulation position of the other species is unknown.ResultsTo assess whether the evolution of genital asymmetry could be linked to the evolution of one-sided mating, we examined phallus morphology and copulation position inD. pacheaand closely related species. The phallus was found to be symmetric in all investigated species exceptD. pachea, which display an asymmetric phallus with a right-sided gonopore, andD. acanthoptera, which harbor an asymmetrically bent phallus. In all examined species, males were found to position themselves symmetrically on top of the female, except inD. pacheaandD. nannoptera, where males mated right-sided, in distinctive, species-specific positions. In addition, the copulation duration was found to be increased innannopteragroup species compared to closely related outgroup species.ConclusionOur study shows that gains, and possibly losses, of asymmetry in genital morphology and mating position have evolved repeatedly in thenannopteragroup. Current data does not allow us to conclude whether genital asymmetry has evolved in response to changes in mating position, or vice versa.


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.


Author(s):  
Kosei Sato ◽  
Daisuke Yamamoto

The main theme of the review is how changes in pheromone biochemistry and the sensory circuits underlying pheromone detection contribute to mate choice and reproductive isolation. The review focuses primarily on gustatory and non-volatile signals in Drosophila. Premating isolation is prevalent among closely related species. In Drosophila, preference for conspecifics against other species in mate choice underlies premating isolation, and such preference relies on contact chemosensory communications between a female and male along with other biological factors. For example, although D. simulans and D. melanogaster are sibling species that yield hybrids, their premating isolation is maintained primarily by the contrasting effects of 7,11-heptacosadiene (7,11-HD), a predominant female pheromone in D. melanogaster, on males of the two species: it attracts D. melanogaster males and repels D. simulans males. The contrasting preference for 7,11-HD in males of these two species is mainly ascribed to opposite effects of 7,11-HD on neural activities in the courtship decision-making neurons in the male brain: 7,11-HD provokes both excitatory and inhibitory inputs in these neurons and differences in the balance between the two counteracting inputs result in the contrasting preference for 7,11-HD, i.e., attraction in D. melanogaster and repulsion in D. simulans. Introduction of two double bonds is a key step in 7,11-HD biosynthesis and is mediated by the desaturase desatF, which is active in D. melanogaster females but transcriptionally inactivated in D. simulans females. Thus, 7,11-HD biosynthesis diversified in females and 7,11-HD perception diversified in males, yet it remains elusive how concordance of the changes in the two sexes was attained in evolution.


1995 ◽  
Vol 69 (5) ◽  
pp. 805-812 ◽  
Author(s):  
Calvin H. Stevens

The discovery of a new locality yielding giant Guadalupian (Lower Permian) fusulinids in east-central Alaska extends the range of these forms much farther north than previously known, and into a tectonostratigraphic terrane from which they previously had not been reported. The number of areas from which giant parafusulinids are known in North America is thus raised to eight. Three of these localities are in rocks that previously had been referred to the allochthonous McCloud belt arc, and one, West Texas, is known to have been part of Paleozoic North America. Comparison of species from all areas suggests that there are two closely related species groups: one represented in Texas and Coahuila, and the other represented in Sonora, northern California, northeastern Washington, southern and northern British Columbia, Alaska, and apparently in Texas. These groups may differ because they are of slightly different ages or because interchange between the faunas of Texas–Coahuila area and the other regions was somewhat inhibited during the Early Permian.


1963 ◽  
Vol 70 (1) ◽  
pp. 17-21
Author(s):  
Merrill H. Sweet

In the course of current work upon the biology and ecology of the Rhyparochrominae of New England, a new species of Ligyrocoris was discovered. The species runs in Barber's (1921) key to the couplet separating diffusus (Uhler) from sylvestris (L.), but is distinct from either species. While the new species is closely related to these species, it is also quite close to L. depictus which is separated out in a different part of Barber's key.These four closely related species are sympatric in New England, although they are markedly different in their overall distribution. The habitat preferences and life cycles of the species are quite different (Sweet, unpublished). The habitat of the new species described below is most unusual for the genus. The greater part of the type series was collected along the margin of a small pond where sedge clumps were standing in the water among occasional exposed rocks rather than in relatively dry fields or slope habitats where the other species occur. The species feeds upon the seeds of the sedge, Carex stricta Lam, and its life cycle is apparently adapted to that of the sedge, which fruits in late May and June. The insect becomes adult in mid-June and lays eggs until mid-July. The eggs remain in diapause over the summer and winter and hatch in May.


Phytotaxa ◽  
2016 ◽  
Vol 263 (2) ◽  
pp. 113 ◽  
Author(s):  
LI-YAUNG KUO ◽  
TIAN-CHUAN HSU ◽  
YI-HAN CHANG ◽  
YAO-MOAN HUANG ◽  
WEN-LIANG CHIOU

Adiantum philippense s.l. is a member of once-pinnate Adiantum but comprise several cytotaxa with different ploidies and reproductive modes. According to the differences of cytotypes, the up-to-date revision had identified three subspecies under the A. philippense complex. In Taiwan, different ploidies and reproductive modes had also been found in this species complex, and existence of (a) cryptic species among these cytotypes had been suggested. The current study focuses on taxonomical revision of Taiwanese A. philippense complex. We sampled not only different Taiwanese cytotypes/populations but also all subspecies under A. philippense and the closely related species of them. By re-examining their phylogeny, ploidies, and reproductive modes, we confirmed that the sexual diploids in Taiwan belong to Adiantum menglianense, and this species is phylogenetically separated from A. philippense. We further approved that A. menglianense can be morphologically distinguished from A. philippense by their frond features and spore numbers in sporangia. Another taxon of Taiwanese A. philippense complex is A. philippense subsp. philippense, which is an apomictic and triploidy subspecies. Additionally, we assigned lectotypes of A. menglianense, and revised the hybrid combination of A. × meishanianum. We also provided a key in order to identify two taxa under Taiwanese A. philippense complex and the other once-pinnate Adiantum species in Taiwan.


1991 ◽  
Vol 69 (1) ◽  
pp. 100-106 ◽  
Author(s):  
Ernest Small ◽  
Brenda Brookes

Little information has been available to justify the species status of the rare Turkmenian Medicago sinskiae Uljan. recognized by Uljanova in 1964. The holotype and plants raised from its seeds were examined, the chromosome number was determined, and a numerical taxonomic comparison was made of M. sinskiae and the other 12 species of Medicago section Spirocarpos subsection Pachyspirae. It was found that M. sinskiae is well separated from the most closely related species of Medicago and deserves recognition at the rank of species. Key words: Medicago sinskiae, Leguminoseae, alfalfa, taxonomy.


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