scholarly journals B Chromosome Variants of the Grasshopper Xyleus discoideus angulatus Are Potentially Derived from Pericentromeric DNA

2017 ◽  
Vol 152 (4) ◽  
pp. 213-221 ◽  
Author(s):  
Andrezza C.S. Bernardino ◽  
Diogo C. Cabral-de-Mello ◽  
Carolina B. Machado ◽  
Octavio M. Palacios-Gimenez ◽  
Neide Santos ◽  
...  
Keyword(s):  
Repetitive Dna ◽  
Evolutionary Dynamics ◽  
Chromosome Evolution ◽  
Pericentromeric Region ◽  
B Chromosome ◽  
B Chromosomes ◽  
Different Populations ◽  
B Chromosome Evolution ◽  
Shed Light

B chromosomes, extra elements present in the karyotypes of some eukaryote species, have been described in the grasshopper Xyleus discoideus angulatus. Although some studies have proposed an autosomal origin of the B chromosome in X. d. angulatus, little is known about its repetitive DNA composition and evolutionary dynamics. The aim of the present work was to shed light on the B chromosome evolution in X. d. angulatus by cytogenetic analysis of 27 populations from Pernambuco and Ceará states (Brazil). The frequency of B chromosomes in the different populations was determined, and chromosome measurements and fluorescence in situ hybridization (FISH) with C0t-DNA and telomeric and B chromosome sequences were performed in cells from B-carrying individuals. The results revealed variations in B chromosome prevalence among the populations and showed that some B chromosomes were smaller in certain populations. FISH produced similar patterns for the C0t-DNA probe in all hybridized individuals, whereas telomeric and B chromosome probes, obtained by microdissection, exhibited variations in their distribution. These results indicate the presence of 3 morphotypes of B chromosomes in X. d. angulatus, with variation in repetitive DNA composition during their evolution. In this species, B chromosomes have an intraspecific origin and probably arose from the pericentromeric region of A chromosomes.

scholarly journals B-chromosome evolution

2000 ◽  
Vol 355 (1394) ◽  
pp. 163-178 ◽  
Author(s):  
Juan Pedro M. Camacho ◽  
Timothy F. Sharbel ◽  
Leo W. Beukeboom
Keyword(s):  
Molecular Evolution ◽  
Repetitive Dna ◽  
Sex Chromosomes ◽  
Chromosome Evolution ◽  
B Chromosome ◽  
B Chromosomes ◽  
Transmission Rates ◽  
Term Evolution ◽  
B Chromosome Evolution

B chromosomes are extra chromosomes to the standard complement that occur in many organisms. They can originate in a number of ways including derivation from autosomes and sex chromosomes in intraand interspecies crosses. Their subsequent molecular evolution resembles that of univalent sex chromosomes, which involves gene silencing, heterochromatinization and the accumulation of repetitive DNA and transposons. B-chromosome frequencies in populations result from a balance between their transmission rates and their effects on host fitness. Their long-term evolution is considered to be the outcome of selection on the host genome to eliminate B chromosomes or suppress their effects and on the B chromosome's ability to escape through the generation of new variants. Because B chromosomes interact with the standard chromosomes, they can play an important role in genome evolution and may be useful for studying molecular evolutionary processes.

scholarly journals Evolution of Plant B Chromosome Enriched Sequences

Genes ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 515 ◽  
Author(s):  
André Marques ◽  
Sonja Klemme ◽  
Andreas Houben
Keyword(s):  
Repetitive Sequences ◽  
B Chromosome ◽  
B Chromosomes ◽  
Dna Elements ◽  
Formation And Evolution ◽  
The Subject ◽  
Chromosome Formation ◽  
The Impact ◽  
Normal Standard ◽  
Shed Light

B chromosomes are supernumerary chromosomes found in addition to the normal standard chromosomes (A chromosomes). B chromosomes are well known to accumulate several distinct types of repeated DNA elements. Although the evolution of B chromosomes has been the subject of numerous studies, the mechanisms of accumulation and evolution of repetitive sequences are not fully understood. Recently, new genomic approaches have shed light on the origin and accumulation of different classes of repetitive sequences in the process of B chromosome formation and evolution. Here we discuss the impact of repetitive sequences accumulation on the evolution of plant B chromosomes.

scholarly journals Isolation of a Pericentromeric Satellite DNA Family in Chnootriba argus (Henosepilachna argus) with an Unusual Short Repeat Unit (TTAAAA) for Beetles

Insects ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 306 ◽  
Author(s):  
Pablo Mora ◽  
Jesús Vela ◽  
Areli Ruiz-Mena ◽  
Teresa Palomeque ◽  
Pedro Lorite
Keyword(s):  
Repetitive Dna ◽  
Satellite Dna ◽  
Repeat Unit ◽  
Pericentromeric Region ◽  
Fish Analysis ◽  
Agricultural Pests ◽  
Base Pairs ◽  
Satellite Dnas ◽  
Repeat Units

Ladybird beetles (Coccinellidae) are one of the largest groups of beetles. Among them, some species are of economic interest since they can act as a biological control for some agricultural pests whereas other species are phytophagous and can damage crops. Chnootriba argus (Coccinellidae, Epilachnini) has large heterochromatic pericentromeric blocks on all chromosomes, including both sexual chromosomes. Classical digestion of total genomic DNA using restriction endonucleases failed to find the satellite DNA located on these heterochromatic regions. Cloning of C0t-1 DNA resulted in the isolation of a repetitive DNA with a repeat unit of six base pairs, TTAAAA. The amount of TTAAAA repeat in the C. argus genome was about 20%. Fluorescence in situ hybridization (FISH) analysis and digestion of chromosomes with the endonuclease Tru9I revealed that this repetitive DNA could be considered as the putative pericentromeric satellite DNA (satDNA) in this species. The presence of this satellite DNA was tested in other species of the tribe Epilachnini and it is also present in Epilachna paenulata. In both species, the TTAAAA repeat seems to be the main satellite DNA and it is located on the pericentromeric region on all chromosomes. The size of this satDNA, which has only six base pairs is unusual in Coleoptera satellite DNAs, where satDNAs usually have repeat units of a much larger size. Southern hybridization and FISH proved that this satDNA is conserved in some Epilachnini species but not in others. This result is in concordance with the controversial phylogenetic relationships among the genera of the tribe Epilachnini, where the limits between genera are unclear.

scholarly journals Genomic Characterization of a B Chromosome in Lake Malawi Cichlid Fishes

2018 ◽  
Author(s):  
Frances Clark ◽  
Matthew Conte ◽  
Thomas Kocher
Keyword(s):  
Dna Sequence ◽  
Sequence Data ◽  
Cichlid Fish ◽  
B Chromosome ◽  
Lake Malawi ◽  
B Chromosomes ◽  
Sequence Coverage ◽  
Specific Sequence ◽  
Genomic Characterization ◽  
B Chromosome Evolution

B chromosomes (Bs) were discovered a century ago, and since then most studies have focused on describing their distribution and abundance using traditional cytogenetics. Only recently have attempts been made to understand their structure and evolution at the level of DNA sequence. Many questions regarding the origin, structure, function and evolution of B chromosomes remain unanswered. Here we identify B chromosome sequences from several species of cichlid fish from Lake Malawi by examining the ratios of DNA sequence coverage in individuals with and without B chromosomes. We examine the efficiency of this method, and compare results using both Illumina and PacBio sequence data. The B chromosome sequences detected in 13 individuals from 7 species were compared to assess the rates of sequence replacement. B-specific sequence common to at least 12 of the 13 datasets are identified as the “Core” B chromosome. The location of B sequence homologs throughout the genome provides further support for theories of B chromosome evolution. Finally, we identified candidate genes located on the B chromosome which may regulate the segregation and maintenance of the B chromosome.

scholarly journals B Chromosomes in Free-Living Flatworms of the Genus Macrostomum (Platyhelminthes, Macrostomorpha)

2021 ◽  
Vol 22 (24) ◽  
pp. 13617
Author(s):  
Kira S. Zadesenets ◽  
Nikolay B. Rubtsov
Keyword(s):  
Genome Duplication ◽  
Natural Populations ◽  
B Chromosome ◽  
Laboratory Culture ◽  
B Chromosomes ◽  
Free Living ◽  
Transmission Rates ◽  
Supernumerary Chromosomes

B chromosomes (Bs) or supernumerary chromosomes are extra chromosomes in the species karyotype that can vary in its copy number. Bs are widespread in eukaryotes. Usually, the Bs of specimens collected from natural populations are the object of the B chromosome studies. We applied another approach analyzing the Bs in animals maintained under the laboratory conditions as lines and cultures. In this study, three species of the Macrostomum genus that underwent a recent whole-genome duplication (WGD) were involved. In laboratory lines of M. lignano and M. janickei, the frequency of Bs was less than 1%, while in the laboratory culture of M. mirumnovem, it was nearer 30%. Their number in specimens of the culture varied from 1 to 14. Mosaicism on Bs was discovered in parts of these animals. We analyzed the distribution of Bs among the worms of the laboratory cultures during long-term cultivation, the transmission rates of Bs in the progeny obtained from crosses of worms with different numbers of Bs, and from self-fertilized isolated worms. The DNA content of the Bs in M. mirumnovem was analyzed with the chromosomal in situ suppression (CISS) hybridization of microdissected DNA probes derived from A chromosomes (As). Bs mainly consisted of repetitive DNA. The cytogenetic analysis also revealed the divergence and high variation in large metacentric chromosomes (LMs) containing numerous regions enriched for repeats. The possible mechanisms of the appearance and evolution of Bs and LMs in species of the Macrostomum genus were also discussed.

scholarly journals Satellite DNAs Unveil Clues about the Ancestry and Composition of B Chromosomes in Three Grasshopper Species

Genes ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 523 ◽  
Author(s):  
Diogo Milani ◽  
Vanessa Bardella ◽  
Ana Ferretti ◽  
Octavio Palacios-Gimenez ◽  
Adriana Melo ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Fluorescent In Situ Hybridization ◽  
B Chromosome ◽  
B Chromosomes ◽  
Satellite Dnas ◽  
Grasshopper Species ◽  
Repetitive Dnas ◽  
Origin And Evolution ◽  
Chromosomal Position

Supernumerary (B) chromosomes are dispensable genomic elements occurring frequently among grasshoppers. Most B chromosomes are enriched with repetitive DNAs, including satellite DNAs (satDNAs) that could be implicated in their evolution. Although studied in some species, the specific ancestry of B chromosomes is difficult to ascertain and it was determined in only a few examples. Here we used bioinformatics and cytogenetics to characterize the composition and putative ancestry of B chromosomes in three grasshopper species, Rhammatocerus brasiliensis, Schistocerca rubiginosa, and Xyleus discoideus angulatus. Using the RepeatExplorer pipeline we searched for the most abundant satDNAs in Illumina sequenced reads, and then we generated probes used in fluorescent in situ hybridization (FISH) to determine chromosomal position. We used this information to infer ancestry and the events that likely occurred at the origin of B chromosomes. We found twelve, nine, and eighteen satDNA families in the genomes of R. brasiliensis, S. rubiginosa, and X. d. angulatus, respectively. Some satDNAs revealed clustered organization on A and B chromosomes varying in number of sites and position along chromosomes. We did not find specific satDNA occurring in the B chromosome. The satDNAs shared among A and B chromosomes support the idea of putative intraspecific ancestry from small autosomes in the three species, i.e., pair S11 in R. brasiliensis, pair S9 in S. rubiginosa, and pair S10 in X. d. angulatus. The possibility of involvement of other chromosomal pairs in B chromosome origin is also hypothesized. Finally, we discussed particular aspects in composition, origin, and evolution of the B chromosome for each species.

scholarly journals Tertiary trisomics in the garden pea as a model of B chromosome evolution in plants

Heredity ◽  
2003 ◽  
Vol 91 (6) ◽  
pp. 577-583 ◽  
Author(s):  
V A Berdnikov ◽  
F L Gorel ◽  
O E Kosterin ◽  
V S Bogdanova
Keyword(s):  
Chromosome Evolution ◽  
B Chromosome ◽  
Garden Pea ◽  
B Chromosome Evolution

scholarly journals Characterization of a Maize Chromosome 4 Centromeric Sequence: Evidence for an Evolutionary Relationship With the B Chromosome Centromere

Genetics ◽  
2001 ◽  
Vol 159 (1) ◽  
pp. 291-302 ◽  
Author(s):  
Brent T Page ◽  
Michael K Wanous ◽  
James A Birchler
Keyword(s):  
Evolutionary Relationship ◽  
Bac Library ◽  
B Chromosome ◽  
B Chromosomes ◽  
Chromosome 4 ◽  
Centromeric Sequence ◽  
Unit Repeat ◽  
Specific Sequences

Abstract Previous work has identified sequences specific to the B chromosome that are a major component of the B centromere. To address the issue of the origin of the B and the evolution of centromere-localized sequences, DNA prepared from plants without B chromosomes was probed to seek evidence for related sequences. Clones were isolated from maize line B73 without B chromosomes by screening DNA at reduced stringency with a B centromeric probe. These clones were localized to maize centromere 4 using fluorescence in situ hybridization. They showed homology to a maize centromere-mapped sequence, to maize B chromosome centromere sequences, and to a portion of the unit repeat of knobs, which act as neocentromeres in maize. A representative copy was used to screen a BAC library to obtain these sequences in a larger context. Each of the six positive BACs obtained was analyzed to determine the nature of centromere 4-specific sequences present. Fifteen subclones of one BAC were sequenced and the organization of this chromosome 4-specific repeat was examined.

scholarly journals Silencing of Transposable Elements Mediated by 5-mC and Compensation of the Heterochromatin Content by Presence of B Chromosomes in Astyanax scabripinnis

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1162
Author(s):  
Patrícia Barbosa ◽  
Zelinda Schemczssen-Graeff ◽  
André Marques ◽  
Maelin da Silva ◽  
Giovani Marino Favero ◽  
...  
Keyword(s):  
Transposable Elements ◽  
Compensation Effect ◽  
Pericentromeric Region ◽  
B Chromosome ◽  
B Chromosomes ◽  
Chromosome 1 ◽  
Complex Processes ◽  
Genome Methylation ◽  
Regulation Mechanisms ◽  
Heterochromatin Content

The way in which transcriptional activity overcomes the physical DNA structure and gene regulation mechanisms involves complex processes that are not yet fully understood. Modifications in the cytosine-guanine sequence of DNA by 5-mC are preferentially located in heterochromatic regions and are related to gene silencing. Herein, we investigate evidence of epigenetic regulation related to the B chromosome model and transposable elements in A. scabripinnis. Indirect immunofluorescence using anti-5-mC to mark methylated regions was employed along with quantitative ELISA to determine the total genomic DNA methylation level. 5-mC signals were dispersed in the chromosomes of both females and males, with preferential accumulation in the B chromosome. In addition to the heterochromatic methylated regions, our results suggest that methylation is associated with transposable elements (LINE and Tc1-Mariner). Heterochromatin content was measured based on the C-band length in relation to the size of chromosome 1. The B chromosome in A. scabripinnis comprises heterochromatin located in the pericentromeric region of both arms of this isochromosome. In this context, individuals with B chromosomes should have an increased heterochromatin content when compared to individuals that do not. Although, both heterochromatin content and genome methylation showed no significant differences between sexes or in relation to the occurrence of B chromosomes. Our evidence suggests that the B chromosome can have a compensation effect on the heterochromatin content and that methylation possibly operates to silence TEs in A. scabripinnis. This represents a sui generis compensation and gene activity buffering mechanism.

Genomic in situ hybridization (GISH) of Tripsacum dactyloides and Zea mays ssp. mays with B chromosomes

Genome ◽  
1999 ◽  
Vol 42 (4) ◽  
pp. 687-691 ◽  
Author(s):  
L Poggio ◽  
V Confalonieri ◽  
C Comas ◽  
A Cuadrado ◽  
N Jouve ◽  
...  
Keyword(s):  
Zea Mays ◽  
In Situ Hybridization ◽  
B Chromosome ◽  
Genomic In Situ Hybridization ◽  
B Chromosomes ◽  
Tripsacum Dactyloides ◽  
Mitotic Chromosomes ◽  
Maize Line ◽  
Total Dna

Genomic affinities between Tripsacum dactyloides (2n = 72) and Zea mays ssp. mays (2n = 20 + 5 B) were analyzed through GISH (genomic in situ hybridization) to ascertain the degree of chromosome homology between the two genera. Mitotic cells of T. dactyloides were simultaneously probed with total genomic DNA from Z. mays ssp .mays (2n = 20) and with rDNA (pTA71). A disperse pattern of hybridization signal among all 72 chromosomes, corresponding to maize total DNA, and six strong fluorescent signals due to the rDNA probe hybridizing on 3 chromosome pairs of T. dactyloides were observed. Mitotic chromosomes from Z. mays ssp. mays (2n = 20 + 5 B) were hybridized with a maize line that lacked B chromosomes and knobs and with total DNA from T. dactyloides. The knobless line of maize hybridized intensely on all chromosomes except for some regions where the probe bound less. Tripsacum dactyloides bound intensely on one terminal region of each B chromosome and to some regions of chromosome pairs 2, 6, and 8. These regions are DAPI positive and coincide with regions that displayed lower affinity with the probe from the knobless maize line. The possible significance of these results is discussed briefly.Key words: Tripsacum dactyloides, Zea mays ssp. mays, maize B chromosomes, genomic in situ hybridization, GISH.

Sign in / Sign up

Export Citation Format

Share Document