Supernumerary chromosome evolution in the Simulium vernum group (Diptera: Simuliidae)

Genome ◽  
1989 ◽  
Vol 32 (4) ◽  
pp. 516-521 ◽  
Author(s):  
Charles Brockhouse ◽  
J. A. B. Bass ◽  
R. M. Feraday ◽  
N. A. Straus
Keyword(s):  
Sibling Species ◽  
Related Species ◽  
Chromosome Evolution ◽  
Polytene Chromosomes ◽  
Nucleolar Organizer ◽  
Chromosome Analysis ◽  
B Chromosome ◽  
Supernumerary Chromosome ◽  
Closely Related Species ◽  
Black Fly

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.

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 ◽  
...  
Keyword(s):  
Sibling Species ◽  
Related Species ◽  
Polytene Chromosomes ◽  
Natural Populations ◽  
Chromosomal Polymorphism ◽  
The Other ◽  
Chironomus Tentans ◽  
Closely Related Species ◽  
Cytogenetic Evolution

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.

scholarly journals Contact-Chemosensory Evolution Underlying Reproductive Isolation in Drosophila Species

2020 ◽  
Vol 14 ◽  
Author(s):  
Kosei Sato ◽  
Daisuke Yamamoto
Keyword(s):  
Decision Making ◽  
Mate Choice ◽  
Reproductive Isolation ◽  
Sibling Species ◽  
Related Species ◽  
Main Theme ◽  
Biological Factors ◽  
Premating Isolation ◽  
Closely Related Species ◽  
Neural Activities

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.

Étude caryologique de trois espèces d’Hypochoeris originaires d'Argentine : H. chillensis, H. microcephala var. albiflora et H. megapotamica

1994 ◽  
Vol 72 (10) ◽  
pp. 1496-1502 ◽  
Author(s):  
S. Siljak-Yakovlev ◽  
A. Bartoli ◽  
G. Roitman ◽  
N. Barghi ◽  
C. Mugnier
Keyword(s):  
Chromosome Number ◽  
Related Species ◽  
Secondary Constriction ◽  
Nucleolar Organizer ◽  
Asymmetry Index ◽  
Evolutionary Trend ◽  
Closely Related Species ◽  
Nucleolar Organizers ◽  
Morphological Differences ◽  
Secondary Constrictions

Three Hypochoeris species from Argentina with the same chromosome number (x = 4) and similar karyotypes (typically bimodal) show significant ecological and morphological differences. Comparative cytogenetic analysis was done for these taxa, producing karyotypes with correlated idiograms. The number of secondary constrictions and nucleolar organizers varied. The results from this study are discussed in terms of the mechanisms of microevolution within this group of closely related species, and in terms of the evolutionary trend in the genus and in the tribe Cichorieae. Key words: Hypochoeris, Cichorieae, bimodal karyotype, secondary constriction, nucleolar organizer, asymmetry index.

scholarly journals Lack of underdominance in a naturally occurring pericentric inversion in Drosophila melanogaster and its implications for chromosome evolution.

Genetics ◽  
1991 ◽  
Vol 129 (3) ◽  
pp. 791-802
Author(s):  
J A Coyne ◽  
S Aulard ◽  
A Berry
Keyword(s):  
Drosophila Melanogaster ◽  
Natural Selection ◽  
Genetic Drift ◽  
Related Species ◽  
Pericentric Inversion ◽  
Chromosome Evolution ◽  
Natural Populations ◽  
Crossing Over ◽  
Closely Related Species ◽  
Naturally Occurring

Abstract In(2LR)PL is a large pericentric inversion polymorphic in populations of Drosophila melanogaster on two Indian Ocean islands. This polymorphism is puzzling: because crossing over in female heterokaryotypes produces inviable zygotes, such inversions are thought to be underdominant and should be quickly eliminated from populations. The observed fixation for such inversions among related species has led to the idea that genetic drift can cause chromosome evolution in opposition to natural selection. We found, however, that In(2LR)PL is not underdominant for fertility, as heterokaryotypic females produce perfectly viable eggs. Genetic analysis shows that the lack of underdominance results from the nearly complete absence of crossing over in the inverted region. This phenomenon is probably caused by mechanical and not genetic factors, because crossing over is not suppressed in In(2LR)PL homokaryotypes. Our observations do not support the idea that the fixation of pericentric inversions among closely related species implies the action of genetic drift overcoming strong natural selection in very small populations. If chromosome arrangements vary in their underdominance, it is those with the least disadvantage as heterozygotes, like In(2LR)PL, that will be polymorphic or fixed in natural populations.

Description of Dineura pullior sp. n. (Hymenoptera: Tenthredinidae), with quantified observations on saw wear

1995 ◽  
Vol 26 (4) ◽  
pp. 385-392 ◽  
Author(s):  
S. Schmidt ◽  
G.H. Walter
Keyword(s):  
Host Plant ◽  
Sibling Species ◽  
Related Species ◽  
Closely Related Species ◽  
Adult Females ◽  
First Time ◽  
Important Character ◽  
Range Of Variation

AbstractIn sawfly taxonomy the structure of the lancet or the saw is an important character for identification of females. Because adult females use the saw to place eggs into the host plant its teeth may wear and their shape may thus be altered. We investigated the pattern of wear in a species of nematine sawfly that we also describe for the first time. Saw wear of females that deposited known numbers of eggs was examined. Saw wear was not strongly related to the number of eggs laid, despite some saws being considerably worn. The range of variation in saw profile illustrated by Lindqvist (1956) in the closely-related species D. virididorsata (Retzius) was not observed in our study. Despite the shape of the saw being altered to some extent with use, other structures on the saw do not change and provide good taxonomic characters in the genus Dineura, as evidenced by our detection of the cryptic (= sibling) species on the basis of differences in ctenidial structure. We describe this species under the name Dineura pullior sp. n.

Ecological characterization of two sibling species, IIIL-1 and IS-7, in the Simulium vittatum complex (Diptera: Simuliidae)

1984 ◽  
Vol 62 (7) ◽  
pp. 1308-1315 ◽  
Author(s):  
Peter H. Adler ◽  
Ke Chung Kim
Keyword(s):  
Sibling Species ◽  
Polytene Chromosomes ◽  
Early Spring ◽  
Eastern United States ◽  
Black Fly ◽  
Geographic Ranges ◽  
Factors Affecting ◽  
Simulium Vittatum ◽  
Simulium Decorum

Larval polytene chromosomes provided the identification tool that enabled ecological characterization of two black fly sibling species, IIIL-1 and IS-7, in the Simulium vittatum complex. A 4-year study in the eastern United States demonstrated important differences between the two siblings, based primarily on differential occupancy of the stream continuum. Immatures of the IIIL-1 sibling predominated below nonspring-fed reservoirs, downstream of sewage effluent outflows, and in warm downstream areas. Immatures of the IS-7 sibling occurred, with IIIL-1, in cool well-oxygenated flows generally associated with groundwater discharge. These sibling–habitat relations produced sibling gradients along the stream continuum. Over their geographic ranges, the IIIL-1 sibling became increasingly abundant from north to south, relative to IS-7. At mixed-sibling sites, populations were asynchronous; IS-7 generally predominated in early spring and late fall. The major determinants of sibling distributions were those factors affecting respiration: temperature, oxygen, and current. Species such as the black fly Simulium decorum and the midge Chironomus riparius signalled essentially pure populations of IIIL-1. Preimaginal densities of Glossosoma spp. (Trichoptera) also indicated sibling proportions. IIIL-1 and IS-7 shared all pathogens. At mixed-sibling sites, proportionally more larvae of IIIL-1 occurred on rocks than on grasses. Regardless of sibling, larvae on rocks were darker than those on grasses, which suggested differences in the proportion of ingested materials.

THE EVOLUTIONARY HISTORY OF DROSOPHILA BUZZATII. III. CYTOGENETIC RELATIONSHIPS BETWEEN TWO SIBLING SPECIES OF THE BUZZATII CLUSTER

Genetics ◽  
1982 ◽  
Vol 101 (3-4) ◽  
pp. 503-518 ◽  
Author(s):  
A Ruiz ◽  
A Fontdevila ◽  
M Wasserman
Keyword(s):  
Salivary Gland ◽  
Sibling Species ◽  
Related Species ◽  
Evolutionary History ◽  
South American ◽  
Closely Related Species ◽  
Drosophila Buzzatii ◽  
Repleta Group ◽  
Chromosomal Data ◽  
History Of

ABSTRACT Drosophila buzzatii has been found sympatric in Argentina with a closely-related sibling species, D. serido. The biogeographical, reproductive and chromosomal data allow us to combine these species into an evolutionary unit, the buzzatii cluster. Salivary gland chromosomes also have been used to determine their phylogenetic relationships with other closely related species, showing that the buzzatii cluster species share two inversions—2d  2 and 2s  6—with the species of the martensis cluster. Both clusters arose from South American populations of the ancestor of the mulleri complex, and we propose to include D. buzzatii and D. serido in the mulleri complex of the repleta group.

The polytene chromosomes of Simulium (Ectemnaspis) ignescens Roubaud and the related species Simulium "C," both from Colombia

1988 ◽  
Vol 66 (2) ◽  
pp. 300-309 ◽  
Author(s):  
Sofia Duque ◽  
Paulina Muñoz de Hoyos ◽  
Klaus Rothfels
Keyword(s):  
Related Species ◽  
Polytene Chromosomes ◽  
Nucleolar Organizer ◽  
Onchocerca Volvulus ◽  
Sex Linkage ◽  
Undescribed Species ◽  
Banding Sequence ◽  
Chromosome Maps ◽  
Chromosome Iii

The paper describes the polytene chromosomes of Simulium (Ectemnaspis) ignescens from Colombia and compares them with those of a sympatric undescribed species designated Simulium "C." The two species share the entire banding sequence of chromosome arms IS, IL, and IIIS. Their IIIL arms differ by a single fixed inversion, but their second chromosomes exhibit multistep arrangement differences that were not completely resolved. The nucleolar organizer of S. ignescens is in the base of IIIS, that of Simulium "C" in the base of IS. Polymorphisms in IIS of S. ignescens exhibit partial sex linkage; no sex differential segments were demonstrated in Simulium "C." Common autosomal polymorphisms of both species involve preferentially chromosome III. Preliminary studies indicate that the chromosome maps of S. ignescens can serve as standards for other neotropical Simulium Latreille species including the important vectors of Onchocerca volvulus and Mansonella ozzardi.

scholarly journals The Broom of the Sorcerer's Apprentice: The Fine Structure of a Chromosomal Region Causing Reproductive Isolation Between Two Sibling Species of Drosophila

Genetics ◽  
1996 ◽  
Vol 143 (3) ◽  
pp. 1287-1298 ◽  
Author(s):  
Andrew W Davis ◽  
Chug-I Wu
Keyword(s):  
Reproductive Isolation ◽  
Sibling Species ◽  
Related Species ◽  
Hybrid Sterility ◽  
Drosophila Genome ◽  
Hybrid Male ◽  
Hybrid Male Sterility ◽  
Closely Related Species ◽  
Drosophila Mauritiana ◽  
Two Factors

Abstract How many genes contribute to reproductive isolation between closely related species? We determined the number of genes located in the 9D-12B region of the Drosophila mauritiana X chromosome that cause hybrid male sterility in a D. simulans background. Previous low resolution studies suggested that a single hybrid sterility factor was associated with this region. In this study, by taking advantage of a cluster of visible and DNA markers, we identified three D. mauritiana factors in this region and then subjected one of them to detailed analysis. This factor again turned out to be comprised of three factors; one of which, mapped to within 200 kb, may in fact be two factors. The title refers to this exercise of splitting sterile introgressions into ever smaller ones, each of which retains partial or full sterility effects. In a region representing a mere 3% of the Drosophila genome, no fewer than six loci of hybrid sterility were identified between two sibling species that have not shown clear divergence at the molecular level. These results suggest that levels of genetic divergence between closely related species may be quite high for functionally important traits even when the opposite is true for randomly chosen loci.

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