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Insects Apr 2024The Maculipennis subgroup of malaria mosquitoes includes both dominant malaria vectors and non-vectors in Eurasia. Understanding the genetic factors, particularly...
The Maculipennis subgroup of malaria mosquitoes includes both dominant malaria vectors and non-vectors in Eurasia. Understanding the genetic factors, particularly chromosomal inversions, that differentiate species can provide valuable insights for vector control strategies. Although autosomal inversions between the species in this subgroup have been characterized based on the chromosomal banding patterns, the number and positions of rearrangements in the X chromosome remain unclear due to the divergent banding patterns. Here, we identified two large X chromosomal inversions, approximately 13 Mb and 10 Mb in size, using fluorescence in situ hybridization. The inversion breakpoint regions were mapped by hybridizing 53 gene markers with polytene chromosomes of . The DNA probes were designed based on gene sequences from the annotated genome. The two nested inversions resulted in five syntenic blocks. Only two small syntenic blocks, which encompass 181 annotated genes in the genome, changed their position and orientation in the X chromosome. The analysis of the genome revealed an enrichment of gene ontology terms associated with immune system and mating behavior in the rearranged syntenic blocks. Additionally, the enrichment of DNA transposons was found in sequences homologous to three of the four breakpoint regions. This study demonstrates the successful application of the physical genome mapping approach to identify rearrangements that differentiate species in insects with polytene chromosomes.
PubMed: 38786868
DOI: 10.3390/insects15050312 -
Journal of Visualized Experiments : JoVE Apr 2024Laboratory stocks of the lower dipteran fly, Bradysia (Sciara) coprophila, have been maintained for over a century. Protocols for laboratory upkeep of B. coprophila are...
Laboratory stocks of the lower dipteran fly, Bradysia (Sciara) coprophila, have been maintained for over a century. Protocols for laboratory upkeep of B. coprophila are presented here. These protocols will be useful for the rapidly increasing number of laboratories studying B. coprophila to take advantage of its unique biological features, which include (1) a monopolar spindle in male meiosis I; (2) non-disjunction of the X dyad in male meiosis II; (3) chromosome imprinting to distinguish maternal from paternal homologs; (4) germ line-limited (L) chromosomes; (5) chromosome elimination (paternal chromosomes in male meiosis I; one to two X chromosomes in early embryos; L chromosomes from the soma in early embryos); (6) sex determination by the mother (there is no Y chromosome); and (7) developmentally regulated DNA amplification at the DNA puff loci in larval salivary gland polytene chromosomes. It is now possible to explore these many unique features of chromosome mechanics by using the recent advances in sequencing and assembly of the B. coprophila genome and the development of transformation methodology for genomic engineering. The growing scientific community that uses B. coprophila for research will benefit from the protocols described here for mating the flies (phenotypic markers for mothers that will have only sons or only daughters; details of mass mating for biochemical experiments), checking embryo hatch, feeding larvae, and other comments on its rearing.
Topics: Animals; Diptera; Female; Male; Models, Animal
PubMed: 38709079
DOI: 10.3791/66751 -
International Journal of Molecular... Apr 2024We developed a procedure for locating genes on polytene chromosomes and described three types of chromosome structures (gray bands, black bands, and interbands), which... (Review)
Review
We developed a procedure for locating genes on polytene chromosomes and described three types of chromosome structures (gray bands, black bands, and interbands), which differed markedly in morphological and genetic properties. This was reached through the use of our original methods of molecular and genetic analysis, electron microscopy, and bioinformatics data processing. Analysis of the genome-wide distribution of these properties led us to a bioinformatics model of the genome organization, in which the genome was divided into two groups of genes. One was constituted by 65, in which the genome was divided into two groups, 62 genes that are expressed in most cell types during life cycle and perform basic cellular functions (the so-called "housekeeping genes"). The other one was made up of 3162 genes that are expressed only at particular stages of development ("developmental genes"). These two groups of genes are so different that we may state that the genome has two types of genetic organization. Different are the timings of their expression, chromatin packaging levels, the composition of activating and deactivating proteins, the sizes of these genes, the lengths of their introns, the organization of the promoter regions of the genes, the locations of origin recognition complexes (ORCs), and DNA replication timings.
Topics: Animals; Genes, Essential; Drosophila; Drosophila melanogaster; Chromatin; Introns
PubMed: 38612878
DOI: 10.3390/ijms25074068 -
Malaria Journal Mar 2024Anopheles vagus (subgenus Cellia) has been identified as a vector for malaria, filariasis, and Japanese encephalitis in Asia. Sporozoites of Plasmodium falciparum and... (Review)
Review
BACKGROUND
Anopheles vagus (subgenus Cellia) has been identified as a vector for malaria, filariasis, and Japanese encephalitis in Asia. Sporozoites of Plasmodium falciparum and Plasmodium vivax have been found in this zoophilic mosquito in Asia and Indonesia. This study systematically reviews publications regarding An. vagus species, variation, bio-ecology, and malaria transmission in various localities in Asia, especially Indonesia, to determine whether the current data support An. vagus as a species complex.
METHODS
The databases Pubmed, Scopus, Europe PMC, and Proquest were searched to identify information regarding the morphology, karyotypes, polytene chromosome, cross-mating, ecology, and molecular identification of An. vagus was then evaluated to determine whether there were possible species complexes.
RESULTS
Of the 1326 articles identified, 15 studies were considered for synthesis. The Anopheles spp. samples for this study came from Asia. Eleven studies used morphology to identify An. vagus, with singular studies using each of karyotype identification, chromosomal polytene identification, and cross-breeding experiments. Ten studies used molecular techniques to identify Anopheles spp., including An. vagus. Most studies discovered morphological variations of An. vagus either in the same or different areas and ecological settings. In this review, the members of An. vagus sensu lato grouped based on morphology (An. vagus, An. vagus vagus, An. vagus limosus, and An. limosus), karyotyping (form A and B), and molecular (An. vagus genotype A and B, An. vagus AN4 and AN5). Genetic analysis revealed a high conservation of the ITS2 fragment among members except for the An. vagus genotype B, which was, in fact, Anopheles sundaicus. This review also identified that An. vagus limosus and An. vagus vagus were nearly identical to the ITS2 sequence.
CONCLUSION
Literature review studies revealed that An. vagus is conspecific despite the distinct morphological characteristic of An. vagus and An. limosus. Further information using another barcoding tool, such as mitochondrial COI and ND6 and experimental cross-mating between the An. vagus and An. limosus may provide additional evidence for the status of An. vagus as a species complex.
Topics: Animals; Phylogeny; Anopheles; Genotype; Mosquito Vectors; Malaria
PubMed: 38539155
DOI: 10.1186/s12936-024-04888-0 -
Insects Feb 2024Discoveries of endemic species highlight areas of biogeographic and conservation interest. Endemic species, however, are often morphologically disguised as more common...
Discoveries of endemic species highlight areas of biogeographic and conservation interest. Endemic species, however, are often morphologically disguised as more common and widespread species. The larval polytene chromosomes revealed a new species of black fly, , from the Djurdjura Mountains of northern Algeria, and its female, male, pupa, and larva are described. The species is chromosomally unique; none of its 11 chromosomal rearrangements are shared with other species. Although the new species structurally resembles (Meigen) with which it previously has been confused, it can be distinguished from all other known species of in the Western Palearctic based on at least one character in each described life stage. Symbiotic organisms included two species of microsporidia, at least one of which is probably undescribed, one unknown protozoan pathogen novel in simuliids, and the trichomycete fungus Léger and Duboscq. Associated simuliid species included at least one new species of the genus . The new species of is tentatively considered endemic to the mountains of northern Algeria but might be expected in the mountains of eastern Morocco and northern Tunisia and perhaps in Sicily. If its endemic status holds, it would be the only nominal species of black fly unique to Algeria.
PubMed: 38535346
DOI: 10.3390/insects15030150 -
Doklady. Biochemistry and Biophysics Dec 2023In Drosophila, a large group of actively transcribed genes is located in pericentromeric heterochromatin. It is assumed that heterochromatic proteins recruit...
In Drosophila, a large group of actively transcribed genes is located in pericentromeric heterochromatin. It is assumed that heterochromatic proteins recruit transcription factors to gene promoters. Two proteins, Ouib and Nom, were previously shown to bind to the promoters of the heterochromatic genes nvd and spok. Interestingly, Ouib and Nom are paralogs of the M1BP protein, which binds to the promoters of euchromatic genes. We have shown that, like M1BP, the Quib and Nom proteins bind to CP190, which is involved in the recruitment of transcription complexes to promoters. Unlike heterochromatic proteins, Ouib and Nom do not interact with the major heterochromatic protein HP1a and bind to euchromatic promoters on polytene chromosomes from the larval salivary glands. The results suggest a new mechanism for the recruitment of transcription factors into the heterochromatic compartment of the nucleus.
Topics: Animals; Drosophila; Drosophila melanogaster; Drosophila Proteins; Heterochromatin; Microtubule-Associated Proteins; Nuclear Proteins; Transcription Factors
PubMed: 38472665
DOI: 10.1134/S1607672924700741 -
Insects Feb 2024(Sauaia & Alves, 1968) is a sciarid that has been continuously cultured in the laboratory for nearly 60 years. Studies on this species have contributed to the...
(Sauaia & Alves, 1968) is a sciarid that has been continuously cultured in the laboratory for nearly 60 years. Studies on this species have contributed to the understanding of DNA puffs, which are characteristic of Sciaridae, and to the knowledge of more general aspects of insect biology, including cell death, nucleolar organization, and the role of the hormone ecdysone during molting. The genome of has now been sequenced, and it is the third publicly available sciarid genome. The aim of this work is to expand the current knowledge on . The morphology of the adults is revisited. The morphology of larvae and pupae is described, together with the behavior of immature stages under laboratory conditions. Cytogenetic maps of the salivary gland polytene chromosomes are presented, together with a comparative analysis of the mitotic chromosomes of six different sciarid species. was originally described as a species of and recently moved to We examine here the systematic position of in the latter genus. Our results extend the characterization of an unconventional model organism and constitute an important resource for those working on the cytogenetics, ecology, taxonomy, and phylogenetic systematics of sciarids.
PubMed: 38392537
DOI: 10.3390/insects15020118 -
Doklady. Biochemistry and Biophysics Dec 2023Polytene chromosomes in Drosophila serve as a classical model for cytogenetic studies. However, heterochromatic regions of chromosomes are typically under-replicated,...
Polytene chromosomes in Drosophila serve as a classical model for cytogenetic studies. However, heterochromatic regions of chromosomes are typically under-replicated, hindering their analysis. Mutations in the Rif1 gene lead to additional replication of heterochromatic sequences, including satellite DNA, in salivary gland cells. Here, we investigated the impact of the Rif1 mutation on heterochromatin in polytene chromosomes formed in ovarian germ cells due to the otu gene mutation. By the analysis of otu; Rif1 double mutants, we found that, in the presence of the Rif1 mutation, ovarian cells undergo additional polytenization of pericentromeric regions. This includes the formation of large chromatin blocks composed of satellite DNA. Thus, the effects of the Rif1 mutation are similar in salivary gland and germ cells. The otu; Rif1 system opens new possibilities for studying factors associated with heterochromatin during oogenesis.
Topics: Animals; Carrier Proteins; Chromosomes; DNA Replication; DNA, Satellite; Drosophila; Drosophila melanogaster; Drosophila Proteins; Germ Cells; Heterochromatin; Polytene Chromosomes
PubMed: 38337102
DOI: 10.1134/S160767292360046X -
Heliyon Jan 2024A novel and distinct mutant with a phenotype, aeroplane wing () is reported for the first time in the urban malaria vector . The main aim of this study was to establish...
A novel and distinct mutant with a phenotype, aeroplane wing () is reported for the first time in the urban malaria vector . The main aim of this study was to establish the mode of inheritance of the gene performing genetic crossings between the mutants and wild types. These mutants show extended open wings that are visible to naked eyes in both the sexes. Mutants were first noticed in a nutritionally stressed isofemale colony. Strategic genetic crosses revealed that the gene is a recessive, autosomal, and monogenic trait having full penetrance with uniform expression in its adult stage. Egg morphometric analysis confirmed that these mutants were intermediate variant. No significant differences were observed in the wing venation and size of mutants compared to their control parental lines. Further cytogenetic analysis on the ovarian polytene chromosome of mutant showed an inversion (3L) on the 3L arm like its parental line. This mutant would be a prominent marker and could be useful to study the functions of related specific genes within its genome.
PubMed: 38187285
DOI: 10.1016/j.heliyon.2023.e23693 -
Doklady. Biochemistry and Biophysics Oct 2023Antibodies to histone modifications and an insulator protein involved in the processes of transcription initiation and elongation are mapped in Drosophila polytene...
Antibodies to histone modifications and an insulator protein involved in the processes of transcription initiation and elongation are mapped in Drosophila polytene chromosomes. The CHRIZ protein (chromatin insulator) and H3K36me3 histone modification (RNA elongation) are detected only in the localization of housekeeping genes (interbands and gray bands of polytene chromosomes) and never in the regions of developmental genes (black bands and large puffs arising from them). Antibodies to H3S10P histone modification, which is associated with the initial elongation of the RNA strand during transcription, are found exclusively in small puffs, but not in housekeeping gene localization sites or large ecdysone-induced puffs, where housekeeping genes are localized. Antibodies to H4R3me2 histone modification (a co-repressor of the ecdysone receptor) are detected only in large ecdysone-induced puffs.
Topics: Animals; Drosophila; Genes, Essential; Histones; Drosophila melanogaster; Ecdysone; Chromosomes; Polytene Chromosomes; RNA; Drosophila Proteins
PubMed: 38093127
DOI: 10.1134/S1607672923700412