Cytogenetic analysis of two related Deltochilum (Coleoptera, Scarabaeidae) species: Diploid number reduction, extensive heterochromatin addition and differentiation

ArticleinMicron 41(2):112-7 · October 2009with2 Reads
DOI: 10.1016/j.micron.2009.10.005 · Source: PubMed
Abstract
Male mitotic and meiotic chromosomes of two species of the genus Deltochilum (Scarabaeidae) were analyzed through conventional staining, C-banding, base-specific fluorochromes, silver nitrate staining (AgNO(3)) and FISH (45S rDNA). The two species possessed karyotypes with 2n=14, neo-XY and meta-submetacentric chromosomes. The analysis of constitutive heterochromatin (CH) revealed mainly diphasic chromosomes in the two species, showing heterochromatic long arms. Silver nitrate staining labeled the blocks corresponding to CH in D. (Deltohyboma) aff morbillosum while in D. (Deltohyboma) calcaratum, AgNO(3) staining revealed only the CH blocks of the diphasic autosomes. The fluorochrome staining revealed in D. (D.) calcaratum the diphasic autosomes and the sex chromosomes with CMA(3)(+) blocks, and in D. (D.) aff morbillosum, the GC-rich sequences were restricted to the terminal regions of the long arms of the pairs 1 and 2 and the X. The FISH revealed 45S rDNA sites in two autosomic pairs and in the X chromosome. The analyses performed allowed for the identification of cytogenetic markers and the discussion of possible chromosome rearrangements that have been involved in the karyotypic differentiation of these species mainly related to the repetitive genome.
    • "In Cassidinae, changes in the distribution of constitutive heterochromatin may ultimately have been the cause of the observed karyotype differentiation, considering that these regions can act in gene regulation and functioning (Henikoff, 2000). Furthermore, it is possible that species that show the same C-band pattern, as in D. cruciata and M. optata, may differ with regard to the molecular constitution of the heterochromatin, such as verifi ed in three Omophoita (Alticinae) species and two Deltochilum (Scarabaeidae ) species (Mello et al., 2010; Mello et al., 2014). In conclusion, the data obtained in this work and those available in the literature have revealed that the diploid number 2n = 18 is not conserved in all Cassidinae tribes, occurring only with high frequency in Cassidini. "
    Full-text · Article · Apr 2016
    • "In Aphididae, a family of Hemiptera with holokinetic chromosomes, three families of repetitive DNA were found: (i) an array of 3.000 bp length associated with a terminal GC-rich region in the X chromosome, (ii) a 200 bp length sequence associated with an AT-rich region of X chromosome, and (iii) a satDNA obtained after HaeIII cleavage associated with ATrich regions of autosomes (Mandrioli et al., 1999). The traditional methods of chromosome banding (C-Giemsa and CMA 3 /DAPI) have been useful for revealing the location, size and AT-or GC-rich composition of heterochromatic regions in the chromosomes and nucleus, and also for producing markers to compare karyotypes of different species and/or groups of insects (Schneider et al., 2006; Bressa et al., 2008; Cabral-de-Mello et al., 2010; Panzera et al., 2010; Bardella et al., 2014). Especially for Triatominae, chromosome banding allows us to identify intraand interspecific variations in the amount and distribution of E-mail addresses: vanessabellini@ig.com.br "
    [Show abstract] [Hide abstract] ABSTRACT: Triatoma infestans, one of the most important vectors of Trypanosoma cruzi, is very interesting model, because it shows large interpopulation variation in the amount and distribution of heterochromatin. This polymorphism involved the three large pairs up to almost all autosomal pairs, including the sex chromosomes. To understand the dynamics of heterochromatin variation in T. infestans, we isolated the AT-rich satDNA portion of this insect using reassociation kinetics (C0t), followed by cloning, sequencing and FISH. After chromosome localization, immunolabeling with anti-5-methylcytosine, anti-H4K5ac and anti-H3K9me2 antibodies was performed to determine the functional characteristics of heterochromatin. The results allowed us to reorganize the karyotype of T. infestans in accordance with the distribution of the families of repetitive DNA using seven different markers. We found that two arrays with lengths of 79 bp and 33 bp length have a strong relationship with transposable element sequences, suggesting that these two families of satDNA probably originated from Polintons. The results also allowed us to identify at least four chromosome rearrangements involved in the amplification/dispersion of AT-rich satDNA of T. infestans. These data should be very useful in new studies including those examining the cytogenomic and population aspects of this very important species of insect.
    Full-text · Article · Apr 2014
    • "The PCR products containing a pool of Mariner sequences , and the C 0 t-1 DNA fraction were labeled with biotin-11-dATP by nick translation using the Bionick Labeling System kit (Invitrogen, San Diego, CA, USA). The FISH protocol followed the adaptations described by Cabral-de-Mello et al. [79]. The probes were labeled with biotin-14-dATP and detected by avidin-FITC (fluorescein isothiocynate) conjugated (Sigma-Aldrich, St. Louis, MO, USA). "
    [Show abstract] [Hide abstract] ABSTRACT: Background With the aim to increase the knowledge on the evolution of coleopteran genomes, we investigated through cytogenetics and nucleotide sequence analysis Mariner transposons in three Scarabaeinae species (Coprophanaeus cyanescens, C. ensifer and Diabroctis mimas). Results The cytogenetic mapping revealed an accumulation of Mariner transposon in the pericentromeric repetitive regions characterized as rich in heterochromatin and C0t-1 DNA fraction (DNA enriched with high and moderately repeated sequences). Nucleotide sequence analysis of Mariner revealed the presence of two major groups of Mariner copies in the three investigated coleoptera species. Conclusions The Mariner is accumulated in the centromeric area of the coleopteran chromosomes probably as a consequence of the absence of recombination in the heterochromatic regions. Our analysis detected high diversification of Mariner sequences during the evolutionary history of the group. Furthermore, comparisons between the coleopterans sequences with other insects and mammals, suggest that the horizontal transfer (HT) could have acted in the spreading of the Mariner in diverse non-related animal groups.
    Full-text · Article · Nov 2013
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