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 Molecular characterization of a maize B chromosome centric sequence.

Genetics ◽  
1993 ◽  
Vol 135 (2) ◽  
pp. 589-597 ◽  
Author(s):  
M R Alfenito ◽  
J A Birchler
Keyword(s):  
In Situ Hybridization ◽  
B Chromosome ◽  
Precise Localization ◽  
Supernumerary Chromosomes ◽  
Centromere Function ◽  
Chromosome Sequence ◽  
Centric Region ◽  
Molecular Nature

Abstract Supernumerary chromosomes are widespread in the plant kingdom but little is known of their molecular nature or mechanism of origin. We report here the initial cloning of sequences from the maize B chromosome. Our analysis suggests that many sequences are highly repetitive and shared with the normal A chromosomes. However, all clones selected for B-specificity contain at least one copy of a particular repeat. Cytological mapping using B chromosome derivatives and in situ hybridization show that the B specific repeats are derived from the centric region of the chromosome. Sequence analysis of this repeat shows homology to motifs mapped to various plant and animal centromeres and to the maize neocentromere. A precise localization of these sequences among breakpoints within the B centromere and an homology to a facultative centromere, suggest a role for this sequence in centromere function.

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.

Karyotype polymorphism in Drosophila albomicans

Genome ◽  
1987 ◽  
Vol 29 (3) ◽  
pp. 395-400 ◽  
Author(s):  
Machiko Hatsumi
Keyword(s):  
Key Words ◽  
Secondary Constriction ◽  
B Chromosome ◽  
B Chromosomes ◽  
Chromosome 4 ◽  
Isofemale Lines ◽  
Heterochromatic Segment ◽  
Drosophila Albomicans ◽  
Karyotype Polymorphism

Supernumerary (B) chromosomes are present in Thai, Malay, and Burmese populations of Drosophila albomicans (2n = 6) in a polymorphic state. Although usually stable at mitosis, their numbers differed between individuals and their frequency was also different between isofemale lines and between populations. Arm 3 of the X3 chromosome was polymorphic for the presence and the size of a procentric heterochromatic segment. Chromosome 4 is polytypic for variation in length governed by differences in the amount of heterochromatin and the long variant is polymorphic for the location of its secondary constriction. Key words: Drosophila albomicans, karyotype polymorphism, B chromosome.

Cloning and Characterization of Maize B Chromosome Sequences Derived From Microdissection

Genetics ◽  
2003 ◽  
Vol 164 (1) ◽  
pp. 299-310 ◽  
Author(s):  
Ya-Ming Cheng ◽  
Bor-Yaw Lin
Keyword(s):  
Heterochromatic Region ◽  
B Chromosome ◽  
Noncoding Region ◽  
Dependent Manner ◽  
Specific Sequence ◽  
Degenerate Oligonucleotide ◽  
Strong Homology ◽  
Similar Location

Abstract Isolation of sequences from the maize B chromosome is always hampered by its high homology with the normal complements. In this study, this handicap was overcome by cloning the sequences from the pachytene B chromosomes dissected out of a slide by a micromanipulator followed by degenerate oligonucleotide-primed PCR. The isolated sequences were found to hybridize with genomic DNA in a B-dosage-dependent manner and with the pachytene B chromosome by fluorescence in situ hybridization (FISH), corroborating their B origin. A total of 19 B sequences were isolated, all of which are repetitive and, with one exception, are homologous to the A chromosome(s). Three sequences have strong homology to maize sequences that include two knob repeats and one zein gene (noncoding region), and 10 others are homologous to the noncoding region of Adh1, Bz1, Gag, Zein, and B centromere to a lesser degree. Six sequences have no homology to any gene. In addition to FISH, the B-specific sequence and a partially B-specific one were also mapped, by seven newly characterized TB-10L translocations, to a similar location on the central portion of the distal heterochromatic region, spreading over a region of about one-third of the B chromosome.

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.

Possible origin of B chromosome in Dichotomius sericeus (Coleoptera)

Genome ◽  
2016 ◽  
Vol 59 (8) ◽  
pp. 575-580 ◽  
Author(s):  
Igor Costa Amorim ◽  
Diogo Milani ◽  
Diogo Cavalcanti Cabral-de-Mello ◽  
Marília França Rocha ◽  
Rita Cássia Moura
Keyword(s):  
Fluorescent In Situ Hybridization ◽  
Dung Beetle ◽  
B Chromosome ◽  
Histone Gene ◽  
B Chromosomes ◽  
Cross Hybridization ◽  
Fluorochrome Staining ◽  
Autosomal Pair ◽  
Ribosomal Dnas

B chromosomes have so far been described in about 80 species of Coleoptera, mainly using conventional staining analysis. In this study, 152 individuals of the dung beetle Dichotomius sericeus (Coleoptera), collected from three isolated geographical areas in the State of Pernambuco, Brazil, were analyzed to determine the frequency, prevalence, distribution, meiotic behavior, and possible B chromosome origin. The cytogenetic analysis consisted of conventional staining, C-banding, triple fluorochrome staining (CMA3/DA/DAPI), and fluorescent in situ hybridization using ribosomal DNAs (rDNAs) and H3 histone gene as probes, as well as microdissection and chromosome painting of the B chromosome. The B chromosomes were detected in all populations analyzed. Analysis revealed the heterochromatic nature and the presence of G+C-rich blocks and 18S rDNA on the B chromosome. FISH with DNA from microdissected B chromosome painted the entire extension of the B chromosome for all populations, besides the pericentromeric regions of all the autosomes, as well as the X chromosome. Finally, cross-hybridization in nine related species of Dichotomius using the microdissected B chromosome as probe did not reveal any hybridization signal. The results suggest an intraspecific and monophyletic origin for B chromosomes in D. sericeus, probably from the second or third autosomal pair.

B-chromosome origin in the endemic New Zealand frog Leiopelma hochstetteri through sex chromosome devolution

Genome ◽  
1998 ◽  
Vol 41 (1) ◽  
pp. 14-22 ◽  
Author(s):  
Timothy F Sharbel ◽  
David M Green ◽  
Andreas Houben
Keyword(s):  
New Zealand ◽  
Sex Chromosome ◽  
Rapid Change ◽  
B Chromosome ◽  
B Chromosomes ◽  
Island Populations ◽  
Repeat Sequences ◽  
Degenerate Oligonucleotide ◽  
Males And Females ◽  
Specific Sequences

The endemic New Zealand frog Leiopelma hochstetteri has variable numbers of mitotically stable B chromosomes. To assess whether the B chromosomes were derived from the autosome complement, they were isolated by micromanipulation and their DNA amplified by degenerate oligonucleotide primed PCR. Southern hybridizations of B chromosome DNA probes to genomic DNA from males and females characterized by differing numbers of B chromosomes demonstrated that the B chromosomes were derived from the univalent W sex chromosome characteristic of North Island populations. The presence of homologous B chromosome specific sequences from geographically distinct populations indicates a single origin of the B chromosomes. Furthermore, a primitive homology shared by B chromosomes and the W sex chromosome from an ancestral WZ/ZZ karyotype, which is still present in frogs from Great Barrier Island, shows that the B chromosomes originated soon after the univalent W sex chromosome had originated. Sequence analysis revealed that B chromosome DNA is composed of repeat sequences and has the potential to form stable hairpin structures. The molecular dynamics of these structures may reflect an inherent propensity to undergo rapid change in nucleotide sequence and chromosome structure.

Cytogenetic Characterization of Two Metynnis Species (Characiformes, Serrasalmidae) Reveals B Chromosomes Restricted to the Females

2019 ◽  
Vol 158 (1) ◽  
pp. 38-45 ◽  
Author(s):  
Ramon M. Favarato ◽  
Leila Braga Ribeiro ◽  
Rafaela P. Ota ◽  
Celeste M. Nakayama ◽  
Eliana Feldberg
Keyword(s):  
5S Rdna ◽  
B Chromosome ◽  
B Chromosomes ◽  
C Banding ◽  
Retrotransposable Elements ◽  
Rdna Sites ◽  
Species Pairs ◽  
Cytogenetic Characterization ◽  
Female Genome

Karyotypes and chromosomal characteristics with focus on B chromosomes of 2 species of the serrasalmid genus Metynnis, namely M. lippincottianus and M. maculatus, were examined using conventional (C-banding) and molecular (FISH mapping of minor and major rDNAs and Rex1, Rex3, and Rex6 retrotransposable elements) protocols. Both species possessed a diploid chromosome number of 2n = 62 and karyotypes composed of 32 metacentric + 28 submetacentric + 2 subtelocentric and 32 metacentric + 26 submetacentric + 4 subtelocentric, respectively; one small B element was found in the female genome of M. lippincottianus. C-banding revealed heterochromatin in the pericentromeric and terminal portions of all chromosomes of both species; the B chromosome was entirely heterochromatic. FISH showed 18S rDNA sites in 2 chromosome pairs in both species (pairs 19 and 22), and a large block in the B chromosome, while 5S rDNA signals were detected in the first pair of subtelocentric chromosomes in both species, moreover in M. maculatus an additional labeled pair 4 was observed. Mapping of the Rex1, Rex3, and Rex6 retrotransposable elements in the genomes of M. lippincottianus and M. maculatus indicated that they were dispersed throughout nearly all the chromosomes of the complement, except for the B chromosome of M. lippincottianus.

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.

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