用RAPD标记探讨金色果蝇复合种内的遗传分化

以随机扩增多态性DNA（RAPD）技术分析了金以果蝇复合种的5个姊妹种（Drosophile auraria、D．biauraria、D.triauraria、D．quadraria和D．subauraria）共12个地理种群的遗传变异。在40种10碱基随机引物中有30种引物对每个种群都可获得令人满意的扩增结果。在161个RAPD标记中有129个呈多态性。以遗传距离为尺度用UPGMA法构建了该复合种的聚类关系图。聚类分析结果结果表明：D.subauraria处于聚类关系图的基部,为该复合种中最早分化的种类;其后才是D.biauraria的分化,而D.auraria和D.quadraria的分化相对较晚。此结果不支持以往认为D.quadraria为金色果蝇复合种祖先种的观点。RAPD分子标记为金色果蝇复合种的系统演化的研究提供了新的、更有价值的信息。     

Geographic variation of reproductive diapause in the Drosophila auraria complex (Diptera: Drosophilidae)

ABSTRACT. In the Drosophila auraria complex (D. auraria Peng, D. biauraria Bock & Wheeler, D. triauraria Bock & Wheeler, D. quadraria Bock & Wheeler and D. subauraria Kimura), D. triauraria from the island of Yaku (30.3N in latitude) and D. quadraria from Taiwan (24.1N) had no or weak diapause, while strains of all the four species from the main islands of Japan had a firm reproductive diapause. These strains entered diapause at short daylengths and the critical daylength was longer and the incidence of diapause higher at a low rather than high temperature. In each species, the critical daylength was longer in strains from higher latitudes. Among sympatric populations of different species, D. subauraria always had the longest critical daylength, while D. auraria had the shortest one. The populations of D. biauraria and D. triauraria had longer critical daylengths than the sympatric populations of D. auraria , but this difference became smaller northwards. Since a longer critical daylength induces diapause earlier in autumn, D. subauraria would enter diapause earliest among these species, and D. auraria would do so latest. The late start of diapause in D. auraria may be related to its adaptation to domestic environments. On the other hand, the adaptive significance of the late start of diapause in northern populations of D. biauraria and D. triauraria is not clear.     

Balbiani rings in Drosophila: the Balbiani ring 1 is a common characteristic in several montium species.

Drosophila bicornuta, D. jambulina, D. biauraria, D. triauraria and D. quadraria, belonging to the montium subgroup of the melanogaster species, have a well-formed Balbiani ring (BR) in their salivary gland chromosomes. The BR has many similarities to the BR1 of D. auraria and D. serrata, two other montium species, indicating that the BR1 is a common characteristic in several species of the montium subgroup. It is suggested that the BR1 structure and its possible function(s), in contrast to the BR2, may have been selected during evolution.     

Molecular phylogeny of the Drosophila auraria species complex and allied species of Japan based on nuclear and mitochondrial DNA sequences

We studied the phylogenetic relationships among the six species of the Drosophila auraria species complex and three species of the montium species subgroup endemic to Japan. To do this, we examined the DNA sequences of the nuclear ITS1 and the mitochondrial COII of these species. Intraspecific variation in ITS1 was observed for most of the species studied. However, interspecific variation was small and of the same magnitude as intraspecific variation among D. auraria, D. triauraria, and D. quadraria. In addition, the amount of intraspecific variation between COII sequences from D. auraria and D. triauraria was almost the same as that of the interspecific variation between these species. Phylogenetic trees based on ITS1 or COII data reveal that, with the exception of D. pectinifera, these species can be separated into two taxonomic groups. D. rufa formed a taxonomic lineage with two Japanese endemic species, D. asahinai and D. lacteicornis. Physiological and behavioral differences between D. auraria and D. triauraria have been reported, but our results differed from those previously reported. Such differences may be better explained by hybridization between D. auraria and D. triauraria than by similarity due to recent common ancestry. Both the ITS1- and COII-based phylogenetic trees placed D. pectinifera outside the auraria complex. However, D. pectinifera sequences were more similar to those of the auraria complex than those of D. punjabiensis, another species thought to be closely related to members of the auraria complex.     

Chromosomal Homology and Molecular Organization of Muller''s Elements D and E in the Drosophila Repleta Species Group

Thirty-three DNA clones containing protein-coding genes have been used for in situ hybridization to the polytene chromosomes of two Drosophila repleta group species, D. repleta and D. buzzatii. Twenty-six clones gave positive results allowing the precise localization of 26 genes and the tentative identification of another nine. The results were fully consistent with the currently accepted chromosomal homologies and in no case was evidence for reciprocal translocations or pericentric inversions found. Most of the genes mapped to chromosomes 2 and 4 that are homologous, respectively, to chromosome arms 3R and 3L of D. melanogaster (Muller's elements E and D). The comparison of the molecular organization of these two elements between D. melanogaster and D. repleta (two species that belong to different subgenera and diverged some 62 million years ago) showed an extensive reorganization via paracentric inversions. Using a maximum likelihood procedure, we estimated that 130 paracentric inversions have become fixed in element E after the divergence of the two lineages. Therefore, the evolution rate for element E is approximately one inversion per million years. This value is comparable to previous estimates of the rate of evolution of chromosome X and yields an estimate of 4.5 inversions per million years for the whole Drosophila genome.     

The Balbiani ring and the polytene chromosomes of Drosophila bicornuta.

A study of the BR1 and of the most prominent puffs during larval development and after in vitro ecdysterone treatment, as well as of the banding pattern and inverted tandem chromosomal duplications of the salivary gland chromosomes of Drosophila bicornuta, is presented in this report. These data are compared and discussed with those of D. auraria and D. serrata, two other montium species.     

Geographic variation and genetic aspects of reproductive diapause in Drosophila triauraria and D. quadraria

ABSTRACT. Geographic variation and genetic aspect of reproductive diapause were studied in Drosophila triauraria Bock & Wheeler and D. quadraria Bock & Wheeler, in relation to their quantitative response to photoperiods. D. quadraria from the subtropical region had no photoperiodic diapause. In D. triauraria strains, diapause was induced under LD 10:14 or 12:12, but not under LD 14:10 or longer photoperiods. Their diapause was induced more effectively and maintained longer by LD 10:14 than by LD 12:12. The duration of diapause was longer in a northern strain, but the diapause inducing process varied little among different geographical strains. Diapause incidence was 50% or lower in F₁ hybrids between D. triauraria and D. quadraria and backcross progenies between F₁ and D. quadraria , and about 70% in backcross progenies between F₁ and D. triauraria under LD 10:14, but very low under LD 12:12. The lower incidence of diapause in these F; and backcross progenies is assumed to be due to the less efficient induction of diapause, since once diapause was induced in them, it was maintained for a long time, especially in the backcross progenies between F₁ and D. triauraria. These experiments suggest that diapause induction and maintenance are different physiological processes controlled by different genetic systems.     

Homoeology of banding sequences and centromeres of Glyptotendipes paripes Edwards, 1929 and G. glaucus meigen, 1818 (Diptera, Chironomidae)

The karyotype analysis of the Glyptotendipes paripes Edwards, 1929 from water reservoirs of Saratov region has been conducted. In the studied population, the following combination of banding sequences predominated: A1.1, B1.1 and G1.1. The frequency of larvae with heterozygous inversions was 72.9 %, the average number of heterozygous inversions per specimen was 0.667, and the most frequent heterozygous inversions were B1.2 (39.5%) and D1.2 (29.2%). Localization of centromeres in the polytene chromosomes G. paripes was defined with the help of C-banding. Homoeology of polytene chromosomes of two chironomidae species (G. paripes and G. glaucus Mg.) has been analyzed and redesignation of chromosomes arms G. paripes has been offered: instead of par D--par A, instead of par C--par B, instead of par A--par D and instead of par B--par C.     

The prominent role of ectopic pairing in the toroidal conformation of Drosophila polytene chromosome bands.

An examination of the polytene chromosomes of some Drosophila species from the montium subgroup, namely, D. auraria, D. serrata, D. jambulina and D. bicornuta, revealed an intimate relationship between ectopic pairing and the toroidal conformation of the polytene chromosome bands. The possible significance of these events is discussed.     

Evolutionary genetics of the Drosophila montium subgroup. I. Reproductive isolations and the phylogeny

Seventeen species of the Drosophila montium subgroup, originated from the Southeast Asia, were genetically examined to clarify the phylogenetic relationships. Among 272 interspecific crosses, 61 combinations were successful in mating and 39 combinations produced hybrid flies. These results enabled us to classify the subgroup into three species complexes: the kikkawai complex (6 species), the jambulina complex (4 species) and the auraria complex (7 species), which were very similar to that obtained by the electrophoretic classification (Ohnishi and Watanabe, 1984). Asymmetrical mating preference between species was found in the present experiment. They were applied to estimate the relative age of species according to the hypothesis proposed by Watanabe and Kawanishi (1979). The evolving order was as follows: kikkawai, leontia, pennae, lini-like, lini, bocki in the kikkawai complex, punjabiensis, punjabiensis-like, jambulina, barbarae in the jambulina complex, and quadraria, yuwanensis, rufa, subauraria, biauraria, triauraria, auraria in the auraria complex. Hybrid flies, if produced, were mostly fertile or partially fertile in both sexes (32/39) within species complex crosses. Therefore premating isolation played a more important role than postmating isolation in speciation of the D. montium subgroup.     

Cytogenetic studies of Lucilia cuprina dorsalis R.-D. (Diptera: Calliphoridae)

Standard photographic maps of the trichogen cell polytene chromosomes are presented. Polytene chromosome locations of 39 mutations have been determined by genetic mapping of autosomal duplications, inversions and translocations. Homologies between the polytene chromosomes of L. cuprina, other Calliphoridae, and Sarcophagidae are noted; genetic linkage groups may have been conserved largely intact during the evolution of the higher Diptera.     

Cytogenetic analysis of Malpighian tubule and salivary gland polytene chromosomes of Bactrocera oleae (Dacus oleae) (Diptera: Tephritidae).

Photomaps of the Malpighian tubule and the salivary gland polytene chromosomes of Bactrocera oleae (Dacus oleae) are presented and compared with those of the fat body. Five polytene chromosomes (10 polytene arms) corresponding to the five autosomes of the mitotic nuclei, as well as a heterochromatic mass corresponding to the sex chromosomes, are observed in the nuclei of the three somatic tissues. The most prominent features of each polytene chromosome, the reverse tandem duplications, as well as the rather unusual ectopic pairing of the telomeric regions of different chromosome arms, are described. The constancy of the banding pattern based on the analysis of the three larval tissues is discussed.     

Intra-and interchromosomal effects of heterozygous inversions on recombination in the third chromosome of Drosophila ananassae

In order to study intra-and interchromosomal effects of heterozygous inversions on recombination in the third chromosome of D.ananassae, experiments were conducted using Stw-pr marker stock and five wild stocks with known karyotypes. The stocks used were homozygous for standard or inverted gene sequence in 2L, 3L, and 3R. Recombination was investigated in both sexes. There was complete absence of crossing-over in males in all the experiments which appeared to be the characteristic of marker stock as spontaneous male crossing-over was reported earlier with the same wild stocks when the second chromosome markers were used. Based on the data of karyotypically homozygous F1 females, the map distance between stw-pr was 36.55 map units. The heterozygosity due to a lengthy inversion in 2L increased the level of crossing-over between stw-pr genes of the third chromosome indicating interchromosomal effect. There was a considerable reduction in the rate of recombination between the same markers due to inversion heterozygosity in 3R indicating intrachromosomal effect. However, 3L inversion heterozygosity had no effect on crossover rate. These results provide evidence for intra-and interchromosomal effects of inversions on crossing-over in the third chromosome of D. ananassae.     

A microsatellite map of the African human malaria vector Anopheles funestus

Microsatellite markers and chromosomal inversion polymorphisms are useful genetic markers for determining population structure in Anopheline mosquitoes. In Anopheles funestus (2N = 6), only chromosome arms 2R, 3R, and 3L are known to carry polymorphic inversions. The physical location of microsatellite markers with respect to polymorphic inversions is potentially important information for interpreting population genetic structure, yet none of the available marker sets have been physically mapped in this species. Accordingly, we mapped 32 polymorphic A. funestus microsatellite markers to the polytene chromosomes using fluorescent in situ hybridization (FISH) and identified 16 markers outside of known polymorphic inversions. Here we provide an integrated polytene chromosome map for A. funestus that includes the breakpoints of all known polymorphic inversions as well as the physical locations of microsatellite loci developed to date. Based on this map, we suggest a standard set of 16 polymorphic microsatellite markers that are distributed evenly across the chromosome complement, occur predominantly outside of inversions, and amplify reliably. Adoption of this set by researchers working in different regions of Africa will facilitate metapopulation analyses of this primary malaria vector.     

Cytotaxonomic characteristics of the genus Glyptotendipes Kieffer (Chironomidae, Diptera) from fish and retention ponds (Silesia, southern Poland)

The cytotaxonomic characteristics of species of the genus Glyptotendipes (Chironomidae): G. glaucus Meigen, G. paripes Edwards, and G. barbipes (Staeger) are described. The studied material was collected from a fish pond at Go?ysz and a sewage retention pond at Chybie in Silesia. All the studied species have the chromosome set 2n = 8, but with many specific structural and functional changes. The cytogenetic data of G. glaucus showed that the studied specimens of this species have been produced by the introgressive hybridization of two sibling species: G. glaucus x G. pallens, and subsequent crossing-over in the hybrid chromosome CD. Owing to this process, the band pattern of chromosome arm D coincided with those of G. pallens. New aberrations (homo- and heterozygous deletions in arm G as well as heterozygous inversions in chromosome arm B) were detected in G. glaucus. Specific band sequences were discovered in chromosomes of G. paripes. The band patterns established in chromosomes AB and G of this species were identical with those of Siberian populations. The banding patterns of the polytene chromosomes of G. barbipes do not differ from the standard. However, high frequency of pericentric inversion of chromosome AB was established. Many new puffs were found in the polytene chromosomes of all the studied species. Their nucleolar organizer was very sensitive to environmental changes. In G. glaucus it appeared in three different states: very active, slightly active, and heterozygous state. The organic pollution existing in the sewage retention pond may contribute to possible mutations and chromosomal damage in Glypotendipes species. Structural and functional rearrangements of the polytene chromosomes of these species mobilized their genomes and provide for survival under polluted conditions.     

The geographic varyability of the polytene chromosome banding sequence of non-biting midje Chironomus pseudothummi str. (Diptera, Chironomidae)

The karyotypes and chromosomal polymorphism of Chironomus pseudothummi were investigated in different parts of its range. It was established that chromosomal variability in the natural populations of this species was represented mainly by the inversion polymorphism of arm G. Only rare and unique inversions were found as heterozygous in arms C, D, and E. In total, the 14 banding sequences of polytene chromosomes form the banding sequences pool of Ch. pseudothummi. Geographic differences in distribution of chromosomal banding sequences throughout the range were established. The presence of banding sequences pstG1 and pstG2 is characteristic of European populations. Banding sequence pstG1 was completely vanished with simultaneous increase in frequency of pstG2 and appearance of new inversion banding sequence pstG3 in Siberian populations. The differences in the set of the rare and unique inversions in arms C, D, and E between west-European and west-Siberian populations were revealed.     

Cytogenetic characteristics of a population of Chironomus riparius Meigen 1804 (Diptera, Chironomidae) from a polluted Po river station

A population of Chironomus riparius from a Po river station near Moncalieri (a trace-metal polluted station) was studied. In this population was established a great variability of band structure of polytene chromosomes as well as paracentric heterozygous inversions, deletions, deficiencies, partial breaks, diploid chromosome fragments, and changes in functional activity and appearance of heterochromatin. In arms A through F, some bands had an increased size compared to the standard chromosomic map. Some bands appeared in a heterozygous or normal homozygous state or were amplified. In all arms, many condensed stable bands appeared in the decondensed state when compared to the standard map. Asynaptic zones in arms E and G as well as heterozygous Balbiani rings and NORs were established. Very often the 4th chromosome was almost completely heteropycnotic and looded like a pompon chromosome. For the first time in this species, a high frequency of ectopic pairings of different arms was observed. Telomeric regions involved in ectopic pairings had a granular appearance, as did some centromeres. The hypothesis is advanced that such a high frequency of structural rearrangements could be correlated with genomic distribution of specific mobile elements.     

Karyotype structure in species of Propsilocerus genus (Diptera, Chironomidae)

Karyotype structure and polytene chromosome banding patterns were studied in two Orthocladiinae siblings--Propsilocerus akamusi (China) and Propsilocerus jacuticus (Russia). Both species have haploid number of chromosome typical for Orthocladiinae (n = 3). An unusual structure of centromeric regions was observed in all three chromosomes of karyotypes in both species. Photomaps of polytene chromosomes are presented. A comparison of karyotypes of P. akamusi and Propsilocerus jacuticus revealed a high level of homology in their banding sequences, however, the presence of fixed paracentric inversions in chromosomal arms IR, IIR, IIIR of Propsilocerus jacuticus has shown a clear-cut phylogenetic divergence. No chromosomal polymorphism was found in both species.     

Polymorphic chromosomal inversions in Anopheles moucheti,a major malaria vector in Central Africa

Anopheles moucheti Evans (Diptera: Culicidae) is a major vector of malaria in forested areas of Central Africa. However, few genetic tools are available for this species. The present study represents the first attempt to characterize chromosomes in An. moucheti females collected in Cameroon. Ovarian nurse cells contained polytene chromosomes, which were suitable for standard cytogenetic applications. The presence of three polymorphic chromosomal inversions in An. moucheti was revealed. Two of these inversions were located on the 2R chromosome arm. The homology between the 2R chromosome arms of An. moucheti and Anopheles gambiae Giles was established by fluorescent in situ hybridization of six An. gambiae genic sequences. Mapping of the probes on chromosomes of An. moucheti detected substantial gene order reshuffling between the two species. The presence of polytene chromosomes and polymorphic inversions in An. moucheti provides a new basis for further population genetic, taxonomic and ecological studies of this neglected malaria vector.     

Geographic variability of the polytene chromosome banding sequence of non-biting midge <Emphasis Type="Italic">Chironomus pseudothummi</Emphasis> Str. (Diptera,Chironomidae)

The karyotypes and chromosomal polymorphism of Chironomus pseudothummi were investigated in different parts of its areal. It was established that chromosomal variability in the natural populations of this species was represented mainly by the inversion polymorphism of arm G. Only rare and unique inversions were found to be heterozygous in arms C, D, and E. In total, 14 banding sequences of polytene chromosomes form the banding sequence pool of C. pseudothummi. Geographic differences in the distribution of chromosomal banding sequences throughout the areal were established. The presence of banding sequences pstG1 and pstG2 is characteristic of European populations. The banding sequence pstG1 disappeared completely with a simultaneous increase in the frequency of pstG2 and with the appearance of a new inversion banding sequence pstG3 in Siberian populations. Differences in the set of rare and unique inversions in arms C, D, and E between the West-European and West-Siberian populations have been revealed.