共查询到20条相似文献,搜索用时 31 毫秒
1.
Xian B. Mardiros Ronni Park Bryan Clifton Gurman Grewal Amina K. Khizar Therese A. Markow 《Fly》2016,10(4):162-171
Speciation can occur through the presence of reproductive isolation barriers that impede mating, restrict cross-fertilization, or render inviable/sterile hybrid progeny. The D. willistoni subgroup is ideally suited for studies of speciation, with examples of both allopatry and sympatry, a range of isolation barriers, and the availability of one species complete genome sequence to facilitate genetic studies of divergence. D. w. willistoni has the largest geographic distribution among members of the Drosophila willistoni subgroup, spanning from Argentina to the southern United States, including the Caribbean islands. A subspecies of D. w. willistoni, D. w. quechua, is geographically separated by the Andes mountain range and has evolved unidirectional sterility, in that only male offspring of D. w. quechua females × D. w. willistoni males are sterile. Whether D. w. willistoni flies residing east of the Andes belong to one or more D. willistoni subspecies remains unresolved. Here we perform fecundity assays and show that F1 hybrid males produced from crosses between different strains found in Central America, North America, and northern Caribbean islands are reproductively isolated from South American and southern Caribbean island strains as a result of unidirectional hybrid male sterility. Our results show the existence of a reproductive isolation barrier between the northern and southern strains and suggest a subdivision of the previously identified D. willistoni willistoni species into 2 new subspecies. 相似文献
2.
A. C. L. Garcia C. Rohde G. F. Audino V. L. S. Valente V. H. Valiati 《Journal of Zoological Systematics and Evolutionary Research》2006,44(3):212-216
The Drosophila willistoni group consists of 23 species of which six are sibling species and belong to the D. willistoni subgroup: D. willistoni, Drosophila equinoxialis, Drosophila tropicalis, Drosophila insularis, Drosophila pavlovskiana and Drosophila paulistorum. These sibling species are abundant in the Neotropical region and can hardly be differentiated by the usual taxonomic traits. Four of them (D. willistoni, D. equinoxialis, D. tropicalis and D. paulistorum) cover extensive geographic distribution areas overlapping in places while two of them are endemic (D. insularis and D. pavlovskiana). In this study, we presented a method for the identification of five sibling species of the D. willistoni subgroup based on the allozyme variation of acid phosphatase‐1 (Acph‐1) in acrylamide gel electrophoresis. Our work showed that Acph‐1 allozyme differences can be used for species‐diagnostic characterization. This method was shown to be a more efficient tool for species identification than others because it is both quicker and produces reliable results. 相似文献
3.
The phylogenetic relationships among nine entities of Drosophila belonging to the D. willistoni subgroup were investigated by establishing the homologous chromosomal segments of IIR chromosome, Muller’s element B (equivalent
to chromosome 2L of D. melanogaster). The sibling species of the D. willistoni group investigated include D. willistoni, D. tropicalis tropicalis, D. tropicalis cubana, D. equinoxialis, D. insularis and four semispecies of the D. paulistorum complex. The phylogenetic relationships were based on the existence of segments in different triads of species, which could
only be produced by overlapping inversions. Polytene banding similarity maps and break points of inversions between species
are presented. The implications of the chromosomal data for the phylogeny of the species and comparisons with molecular data
are discussed. The aim of this study is to produce phylogenetic trees depicting accurately the sequence of natural events
that have occurred in the evolution of these sibling species.
Claudia Rohde, Ana Cristina Lauer Garcia: These authors contributed equally to this work 相似文献
4.
Summary The authors examined seasonal and plant food preferences of members of Drosophila willistoni group in three different ecosystems in Colombia. The results show that there are seasonal preferences as well as food preferences. Furthermore, there exist clear cut temporal (hours of the day) selection which would make possible the sympatric exploitation of equal ecological niches. Comparisons with melanogaster species and with obscura species group are also made. 相似文献
5.
Garcia RN D'Avila MF Robe LJ Loreto EL Panzera Y de Heredia FO Valente VL 《Genetica》2007,131(1):91-105
DNA methylation has been studied abundantly in vertebrates and recent evidence confirms that this phenomenon could be disseminated
among some invertebrates groups, including Drosophila species. In this paper, we used the Methylation-Sensitive Restriction Endonuclease (MSRE) technique and Southern blot with specific probes, to detect methylation in the Drosophila willistoni species. We found differential cleavage patterns between males and females that cannot be explained by Mendelian inheritance,
pointing to a DNA methylation phenomenon different from the Drosophila melanogaster one. The sequencing of some of these bands showed that these fragments were formed by different DNA elements, among which
rDNA. We also characterized the D. willitoni dDnmt2 sequence, through a Mega Blast search against the D. willistoni Trace Archive Database using the D. melanogaster
dDnmt2 nucleotide sequence as query. The complete analysis of D. willistoni dDnmt2 sequence showed that its promoter region is larger, its dDnmt2 nucleotide sequence is 33% divergent from the D. melanogaster one, Inverted Terminal Repeats (ITRs) are absent and only the B isoform of the enzyme is produced. In contrast, ORF2 is more conserved. Comparing the D. willistoni and D. melanogaster dDnmt2 protein sequences, we found higher conservation in motifs from the large domain, responsible for the catalysis of
methyl transfer, and great variability in the region that carries out the recognition of specific DNA sequences (TRD). Globally,
our results reveal that methylation of the D. willistoni genome could be involved in a singular process of species-specific dosage compensation and that the DNA methylation in the
Drosophila genus can have diverse functions. This could be related to the evolutionary history of each species and also to the acquisition
time of the dDnmt2 gene. 相似文献
6.
H. F. Hoenigsberg M. Ordoñez M. M. E. De Polanco A. Espinel 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1982,61(2):183-191
Summary Through a series of genetic load studies made on 1) samples of Drosophila willistoni from two sites in Mesitas, Colombia, it was found that the relative contributions to the total, subvital and lethal loads reflect lethal equivalences (B/A) ratios which support more the balancing theory of population structure than the neutralist theory. Moreover, measurements of population size have revealed the existance of very small demes in local populations. Under such conditions we have calculated extremely small lethal equivalence ratios in demes where probably a great deal of consanguinity takes place. We are aware that under these conditions B/A ratios cannot be very good monitors of random load measurements and, therefore, suggest a change in the mathematical formulation that take into consideration the existance of small populations.Furthermore, it appears plausible that the degree of penetrance in the heterozygous condition changes as the population structure changes. We speculate that natural populations may have unknown selective mechanisms capable of guiding unknown dominance modifiers according to the intensity of selection. 相似文献
7.
The Drosophila willistoni subgroup represents a complex with varying taxonomic levels. It encompasses D. willistoni and its five sibling species: D. equinoxialis, D. insularis, D. paulistorum, D. pavlovskiana and D. tropicalis. Of these, D. equinoxialis, D. tropicalis and D. willistoni present differentiation at subspecific level, whereas D. paulistorum represents a superspecies, formed by six semispecies. Despite this taxonomic and evolutionary complexity, many of these semi
and subspecific taxa have not yet had their phylogenetic status tested in an explicitly molecular study. Aiming to contribute
to the understanding of the evolution of this challenging group, we analyzed nucleotide sequences from two mitochondrial and
four nuclear datasets, both individually and simultaneously, through different phylogenetic methods. High levels of incongruence
were detected among partitions, especially concerning the mitochondrial sequences. As this incongruence was found to be statistically
significant and robust to the use of different models and approaches, and basically restricted to mitochondrial loci, we suggest
that it may stem mainly from hybridization-mediated asymmetrical introgression. Despite this, our nuclear data finally led
to a phylogenetic hypothesis which further refines several aspects related to the willistoni subgroup phylogeny. In this respect, D. insularis, D. tropicalis, D. willistoni and D. equinoxialis successively branched off from the willistoni subgroup main stem, which recently subdivided to produce D. paulistorum and D. pavlovskiana. As regards the semispecies evolution, we found evidence of a recent diversification, which highly influenced the obtained
results due to the associated small levels of genetic differentiation, further worsened by the possibly associated incompletely
sorted ancestral polymorphisms and by the possibility of introgression. This study also raises the question of whether these
semispecies are monophyletic at all. This reasoning is particularly interesting when one considers that similar levels of
reproductive isolation could be attained through infection with different Wolbachia strains. 相似文献
8.
We have studied allelic variation at 28 loci coding for soluble enzymes in three sibling species of Drosophila. The average proportion of polymorphic loci per population is 58% in D. willistoni, 71% in D. equinoxialis, and 60% in D. tropicalis. An individual of any one of these three species is heterozygous at 18–22% of its genes. The correlation between the amount of polymorphism at a given locus and the equilibrium constant of the reaction catalyzed by the corresponding enzyme is not significantly different from zero. We have separated enzymes into those involved in glucose metabolism (group I) and all other enzymes (group II). The genes coding for group II enzymes are about twice as polymorphic as those coding for group I enzymes.This investigation was supported by NSF grants GB 20694 and GB 30895. 相似文献
9.
Ylenia Chiari Kirstin Dion James Colborn Aristeidis Parmakelis Jeffrey R. Powell 《Journal of molecular evolution》2010,70(4):339-345
The best documented selection-based hypothesis to explain unequal usage of codons is based on the relative abundance of isoaccepting
tRNAs. In unicellular organisms the most used codons are optimally translated by the most abundant tRNAs. The chemical bonding
energies are affected by modification of the four traditional bases, in particular in the first anti-codon corresponding to
the third codon position. One nearly universal modification is queuosine (Q) for guanine (G) in tRNAHis, tRNAAsp, tRNAAsn, and tRNATyr; this changes the optimal binding from codons ending in C to no preference or a slight preference for U-ending codons. Among
species of Drosophila, codon usage is constant with the exception of the Drosophila willistoni lineage which has shifted primary usage from C-ending codons to U/T ending codons only for these four amino acids. In Drosophila melanogaster Q containing tRNAs only predominate in old adults. We asked the question whether in D. willistoni these Q containing tRNAs might predominate earlier in development. As a surrogate for levels of modification we studied the
expression of the gene (tgt) coding for the enzyme that catalyzes the substitution of Q for G in different life stages of D. melanogaster, D. pseudoobscura, and D. willistoni. Unlike the other two species, the highest tgt expression in D. willistoni is in young females producing eggs. Because tRNAs laid down in eggs persist through the early stages of development, this
implies that Q modification occurs earlier in development in D. willistoni than in other Drosophila. 相似文献
10.
Drosophila willistoni was the subject of intensive allozyme studies and the locus coding for alcohol dehydrogenase (Adh) was found to be virtually monomorphic. DNA sequence analysis of 18 alleles throughout the distribution of the species has
revealed six replacement polymorphisms. The ratio of replacement to silent polymorphisms is higher in D. willistoni than in any other Drosophila species studied for Adh nucleotide variation. Also in contrast to other species, the variation in introns and noncoding DNA is about the same as
in the coding region. We speculate that both these differences indicate D. willistoni has historically had a small population size possibly related to Pleistocene refugia in the Neotropics.
Received: 5 August 1996 / Accepted: 12 April 1997 相似文献
11.
Experiments are reported in which genetically different strains of Drosophila willistoni compete with D. pseudoobscura. The competition was studied at three temperatures, 20°, 22°, and 25°C. The outcome of the competition depends on the genetic constitution of the competing species, but at 25° and 22°C D. willistoni flies are generally stronger competitors than D. pseudoobscura, while at 20°C D. pseudoobscura generally has a competitive advantage. There is a significant interaction between genotype and temperature; the strain RP3 is the weakest competitor of all D. willistoni strains at 22° and 25°C, but not at 20°C; the strain M18 is the best competitor at 20° and 22°C but not at 25°C.The performance of the four strains of D. willistoni was measured in two more ways. First we estimated their Darwinian fitness relative to other genotypes of the same species. Second, we measured the average population size of each strain in pure culture. There is no significant correlation between population size in pure culture and either competitive fitness or Darwinian fitness. There is, however, a strong positive correlation between Darwinian fitness and interspecific competitive fitness.It is pointed out that natural selection leads to an increase in the average Darwinian fitness of a population but not necessarily to an increase in its adaptedness to the environment. Yet the synthetic theory of evolution assumes that the genes and genotypes favored by natural selection are usually those which increase the adaptedness of their carriers to the environments where they live. The correlation between Darwinian fitness and adaptedness needs to be studied experimentally.This work was supported by NSF grant GB-12562 (International Biological Program), AEC contract AT-(30-1)-3096, and PHS Career Development Award K3GM 37265 to F. J. Ayala. The senior author's stay in New York was financed in part by Research Fellowship 2-12861 from the Panamerican Union. 相似文献
12.
We studied the occurrence of O-type P elements in at least one species of each subgroup of the saltans group, in order to better understand the phylogenetic relationships among the elements within the saltans group and with those of species belonging to the willistoni group. We found that the O-type subfamily has a patchy distribution within the saltans group (it does not occur in D. neocordata and D. emarginata), low sequence divergence among species of the saltans group as well as in relation to species of the willistoni group, a lower rate of synonymous substitution for coding sequences compared to Adh, and phylogenetic incongruities. These findings suggest that the evolutionary history of the O-type subfamily within the
saltans and willistoni groups follows the same model proposed for the canonical subfamily of P elements, i.e., events of horizontal transfer between species of the saltans and willistoni groups. 相似文献
13.
Marícia Fantinel D’Ávila Rosane Nunes Garcia Yanina Panzera Vera Lúcia da Silva Valente 《Genetica》2010,138(8):907-913
Epigenetic phenomena have been widely characterized in the genomes of vertebrates and DNA methylation is a key mechanism of
epigenetic regulation. The DNA methylation systems of invertebrates and vertebrates show several notable differences. However,
the evolutionary implications of those differences only recently began to be revealed. Our study investigated the recurrence
of sex-specific methylation, as previously described for the species Drosophila willistoni, in other species of the Sophophora subgenus that present close evolutionary relationship. The MSRE and Southern blot techniques were used to analyze rDNA of
some species of the willistoni, melanogaster, saltans and obscura groups of Drosophila and the results suggested that differential DNA methylation between sexes only occurs in Drosophila tropicalis and D. insularis, two sibling species of the willistoni subgroup. However, only using the MSRE technique we could detect sex-specific patterns of DNA methylation in all species
of willistoni subgroup. These results indicate that DNA methylation may present important differences, even between closely related species,
shedding new light on this Neotropical species complex. 相似文献
14.
Sebastián Pita Yanina Panzera Vera Lúcia da Silva Valente Zilpa das Graças Silva de Melo Carolina Garcia Ana Cristina Lauer Garcia Martín Alejandro Montes Claudia Rohde 《Genetica》2014,142(5):397-403
Comparative genomics in Drosophila began in 1940, when Muller stated that the ancestral haploid karyotype of this genus is constituted by five acrocentric chromosomes and one dot chromosome, named A to F elements. In some species of the willistoni group such as Drosophila willistoni and D. insularis, the F element, instead of a dot chromosome, has been incorporated into the E element, forming chromosome III (E + F fusion). The aim of this study was to investigate the scope of the E + F fusion in the willistoni group, evaluating six other species. Fluorescent in situ hybridization was used to locate two genes of the F element previously studied—cubitus interruptus (ci) and eyeless (ey)—in species of the willistoni and bocainensis subgroups. Moreover, polytene chromosome photomaps corresponding to the F element (basal portion of chromosome III) were constructed for each species studied. In D. willistoni, D. paulistorum and D. equinoxialis, the ci gene was located in subSectction 78B and the ey gene in 78C. In D. tropicalis, ci was located in subSection 76B and ey in 76C. In species of the bocainensis subgroup, ci and ey were localized, respectively, at subsections 76B and 76C in D. nebulosa and D. capricorni, and 76A and 76C in D. fumipennis. Despite the differences in the subsection numbers, all species showed the same position for ci and ey. The results confirm the synteny of E + F fusion in willistoni and bocainensis subgroups, and allow estimating the occurrence of this event at 15 Mya, at least. 相似文献
15.
Juliana W Gon?alves Victor Hugo Valiati Alejandra Delprat Vera L S Valente Alfredo Ruiz 《BMC genomics》2014,15(1)
Background
Galileo is one of three members of the P superfamily of DNA transposons. It was originally discovered in Drosophila buzzatii, in which three segregating chromosomal inversions were shown to have been generated by ectopic recombination between Galileo copies. Subsequently, Galileo was identified in six of 12 sequenced Drosophila genomes, indicating its widespread distribution within this genus. Galileo is strikingly abundant in Drosophila willistoni, a neotropical species that is highly polymorphic for chromosomal inversions, suggesting a role for this transposon in the evolution of its genome.Results
We carried out a detailed characterization of all Galileo copies present in the D. willistoni genome. A total of 191 copies, including 133 with two terminal inverted repeats (TIRs), were classified according to structure in six groups. The TIRs exhibited remarkable variation in their length and structure compared to the most complete copy. Three copies showed extended TIRs due to internal tandem repeats, the insertion of other transposable elements (TEs), or the incorporation of non-TIR sequences into the TIRs. Phylogenetic analyses of the transposase (TPase)-encoding and TIR segments yielded two divergent clades, which we termed Galileo subfamilies V and W. Target-site duplications (TSDs) in D. willistoni Galileo copies were 7- or 8-bp in length, with the consensus sequence GTATTAC. Analysis of the region around the TSDs revealed a target site motif (TSM) with a 15-bp palindrome that may give rise to a stem-loop secondary structure.Conclusions
There is a remarkable abundance and diversity of Galileo copies in the D. willistoni genome, although no functional copies were found. The TIRs in particular have a dynamic structure and extend in different ways, but their ends (required for transposition) are more conserved than the rest of the element. The D. willistoni genome harbors two Galileo subfamilies (V and W) that diverged ~9 million years ago and may have descended from an ancestral element in the genome. Galileo shows a significant insertion preference for a 15-bp palindromic TSM.Electronic supplementary material
The online version of this article (doi:10.1186/1471-2164-15-792) contains supplementary material, which is available to authorized users. 相似文献16.
Background
Several lines of evidence suggest that codon usage in the Drosophila saltans and D. willistoni lineages has shifted towards a less frequent use of GC-ending codons. Introns in these lineages show a parallel shift toward a lower GC content. These patterns have been alternatively ascribed to either a shift in mutational patterns or changes in the definition of preferred and unpreferred codons in these lineages. 相似文献17.
Summary This report describes the distribution of P-element sequences among members of the closely relatedwillistoni andsaltans species groups of the subgenusSophophora. Gel-blotting analyses showed that many, but not all, species from each of these groups possess sequences with homology to the P transposable element ofDrosophila melanogaster, a sophophoran species belonging to themelanogaster species group. Furthermore, P-homologous fragments are present in lower numbers inwillistoni- andsaltans-group species than inD. melanogaster P strains, and, in some species of those two groups, exhibit species-characteristic hybridization patterns. On the basis of these results, it is proposed that P elements have had a long evolutionary history in thewillistoni andsaltans lineages. 相似文献
18.
Dr. Costas D. Kastritsis 《Chromosoma》1967,23(2):180-202
Ninety-six geographical strains distributed among the incipient species of the Drosophila paulistorum complex were examined cytologically, and the results obtained were correlated with available data on hybridization tests and chromosomal analysis. The complex was found to contain more than sixty-three different inversions, out of which thirty-two were 3rd chromosome configurations. This placed Drosophila paulistorum among the most chromosomally polymorphic species in the genus. The species differs from D. willistoni, in that a great number of inversions is concentrated in one of the chromosomes, as opposed to approximately equal distribution of inversions in the chromosomes of willistoni. — The data obtained in the course of this investigation seem to support the idea that either massive populations become isolated and then form new species, or that the newly forming species tend to retain some of their ancestral polymorphs which might present them with heterotic effects, gradually replacing them with more successful combinations as speciation progresses.The work reported in this article has been carried under Contract No. AT (30-1)-3096, U. S. Atomic Energy Commission. 相似文献
19.
The so called races of Drosophila paulistorum from South America are so deeply isolated ethologically that although still partially bridged by gene flow through hybridization, they should be considered as 6 separate sibling species just as the willistoni group to which D. paulistorum itself belongs. The present article emphasizes the way in which isolation is implemented.This paper is dedicated to him on his 72nd birthday for his many contributions to our field. 相似文献
20.
Rebeca Zanini Mário Josias Müller Gilberto Cavalheiro Vieira Victor Hugo Valiati Maríndia Deprá 《Fly》2018,12(2):81-94
The willistoni species subgroup has been the subject of several studies since the latter half of the past century and is considered a Neotropical model for evolutionary studies, given the many levels of reproductive isolation and different evolutionary stages occurring within them. Here we present for the first time a phylogenetic reconstruction combining morphological characters and molecular data obtained from 8 gene fragments (COI, COII, Cytb, Adh, Ddc, Hb, kl-3 and per). Some relationships were incongruent when comparing morphological and molecular data. Also, morphological data presented some unresolved polytomies, which could reflect the very recent divergence of the subgroup. The total evidence phylogenetic reconstruction presented well-supported relationships and summarized the results of all analyses. The diversification of the willistoni subgroup began about 7.3 Ma with the split of D. insularis while D.paulistorum complex has a much more recent diversification history, which began about 2.1 Ma and apparently has not completed the speciation process, since the average time to sister species separation is one million years, and some entities of the D. paulistorum complex diverge between 0.3 and 1 Ma. Based on the obtained data, we propose the categorization of the former “semispecies” of D. paulistorum as a subspecies and describe the subspecies D. paulistorum amazonian, D. paulistorum andeanbrazilian, D. paulistorum centroamerican, D. paulistorum interior, D. paulistorum orinocan and D. paulistorum transitional. 相似文献