scholarly journals Evidence of the occurrence of structural chromosome changes at the initial diploid diversification of the autopolyploid Turnera sidoides L. (Passifloraceae) complex

Genome ◽  
2016 ◽  
Vol 59 (2) ◽  
pp. 127-136
Author(s):  
Juan M. Roggero Luque ◽  
E.M. Sara Moreno ◽  
I. Evelin Kovalsky ◽  
J. Guillermo Seijo ◽  
Viviana G. Solís Neffa
Keyword(s):  
5S Rdna ◽  
Chromosome Analysis ◽  
Dapi Staining ◽  
Chromosome Markers ◽  
Rdna Loci ◽  
Structural Chromosome ◽  
Turnera Sidoides ◽  
Perennial Herbs ◽  
Diploid Level ◽  
Secondary Constrictions

Turnera sidoides is an autopolyploid complex of obligate outcrossing perennial herbs. It includes five subspecies and five morphotypes in which diploid to octoploid cytotypes were found. Based on phenetic analyses of the complex and karyotype data of polyploid cytotypes, it has been hypothesized that morphological and chromosome differentiation of T. sidoides occurred at the diploid level. To test this hypothesis, we present the first detailed chromosome analysis of diploid populations of three subspecies and four morphotypes. CMA+/DAPI− bands were restricted to secondary constrictions (except in the andino morphotype) and varied in number and position among taxa. By contrast, DAPI staining was uniform in all the materials investigated. The number and position of 45S rDNA loci were coincident with the CMA+/DAPI− bands associated with secondary constrictions. Only one pair of 5S rDNA loci was detected in all the taxa (except in subsp. holosericea), but its position was variable. The identified chromosome markers varied among the three subspecies analyzed, but they were more conserved among the morphotypes of subsp. pinnatifida. Cluster analysis of these chromosome markers supports the current taxonomic arrangement of diploids and demonstrates that structural chromosome changes would have led or accompanied the initial differentiation of T. sidoides at the diploid level.

scholarly journals Genetic ancestry inferred from autosomal and Y chromosome markers and HLA genotypes in Type 1 Diabetes from an admixed Brazilian population

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rossana Santiago de Sousa Azulay ◽  
Luís Cristóvão Porto ◽  
Dayse Aparecida Silva ◽  
Maria da Glória Tavares ◽  
Roberta Maria Duailibe Ferreira Reis ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
Native American ◽  
Y Chromosome ◽  
Chromosome Analysis ◽  
Brazilian Population ◽  
Genetic Ancestry ◽  
Sample Sizes ◽  
Chromosome Markers ◽  
Hla Genotypes

AbstractThis study aimed to investigate the relationship between genetic ancestry inferred from autosomal and Y chromosome markers and HLA genotypes in patients with Type 1 Diabetes from an admixed Brazilian population. Inference of autosomal ancestry; HLA-DRB1, -DQA1 and -DQB1 typifications; and Y chromosome analysis were performed. European autosomal ancestry was about 50%, followed by approximately 25% of African and Native American. The European Y chromosome was predominant. The HLA-DRB1*03 and DRB1*04 alleles presented risk association with T1D. When the Y chromosome was European, DRB1*03 and DRB1*04 homozygote and DRB1*03/DRB1*04 heterozygote genotypes were the most frequent. The results suggest that individuals from Maranhão have a European origin as their major component; and are patrilineal with greater frequency from the R1b haplogroup. The predominance of the HLA-DRB1*03 and DRB1*04 alleles conferring greater risk in our population and being more frequently related to the ancestry of the European Y chromosome suggests that in our population, the risk of T1D can be transmitted by European ancestors of our process miscegenation. However, the Y sample sizes of Africans and Native Americans were small, and further research should be conducted with large mixed sample sizes to clarify this possible association.

scholarly journals Q- AND C-BAND CHROMOSOME MARKERS IN INBRED STRAINS OF MUS MUSCULUS

Genetics ◽  
1976 ◽  
Vol 84 (1) ◽  
pp. 67-75
Author(s):  
D A Miller ◽  
R Tantravahi ◽  
V G Dev ◽  
O J Miller
Keyword(s):  
Mus Musculus ◽  
Inbred Strains ◽  
Normal Chromosome ◽  
Rrna Genes ◽  
Chromosome Markers ◽  
Band Region ◽  
Secondary Constrictions

ABSTRACT Differences in the number of chromosomes with secondary constrictions and in the size of the C-band region on certain chromosomes have been observed among the following inbred strains of Mus musculus: C57BL/10J, C57BR/cdJ, DBA/1J, CBA/J, BALB/cJ, and AKR. These differences are useful as indicators of the location of rRNA genes and as normal chromosome markers. The size of each C-band region appears to remain constant over many generations. Only one probable change in the size of a C-band region was found.

The use of double fluorescence in situ hybridization to physically map the positions of 5S rDNA genes in relation to the chromosomal location of 18S–5.8S–26S rDNA and a C genome specific DNA sequence in the genus Avena

Genome ◽  
1996 ◽  
Vol 39 (3) ◽  
pp. 535-542 ◽  
Author(s):  
Concha Linares ◽  
Juan González ◽  
Esther Ferrer ◽  
Araceli Fominaya
Keyword(s):  
In Situ Hybridization ◽  
Dna Sequence ◽  
Diploid Species ◽  
5S Rdna ◽  
Rdna Genes ◽  
26S Rdna ◽  
A Genome ◽  
Rdna Loci ◽  
C Genome

A physical map of the locations of the 5S rDNA genes and their relative positions with respect to 18S–5.8S–26S rDNA genes and a C genome specific repetitive DNA sequence was produced for the chromosomes of diploid, tetraploid, and hexaploid oat species using in situ hybridization. The A genome diploid species showed two pairs of rDNA loci and two pairs of 5S loci located on both arms of one pair of satellited chromosomes. The C genome diploid species showed two major pairs and one minor pair of rDNA loci. One pair of subtelocentric chromosomes carried rDNA and 5S loci physically separated on the long arm. The tetraploid species (AACC genomes) arising from these diploid ancestors showed two pairs of rDNA loci and three pairs of 5S loci. Two pairs of rDNA loci and 2 pairs of 5S loci were arranged as in the A genome diploid species. The third pair of 5S loci was located on one pair of A–C translocated chromosomes using simultaneous in situ hybridization with 5S rDNA genes and a C genome specific repetitive DNA sequence. The hexaploid species (AACCDD genomes) showed three pairs of rDNA loci and six pairs of 5S loci. One pair of 5S loci was located on each of two pairs of C–A/D translocated chromosomes. Comparative studies of the physical arrangement of rDNA and 5S loci in polyploid oats and the putative A and C genome progenitor species suggests that A genome diploid species could be the donor of both A and D genomes of polyploid oats. Key words : oats, 5S rDNA genes, 18S–5.8S–26S rDNA genes, C genome specific repetitive DNA sequence, in situ hybridization, genome evolution.

Detection of a variable number of 18S-5.8S-26S and 5S ribosomal DNA loci by fluorescent in situ hybridization in diploid and tetraploid Arachis species

Genome ◽  
1999 ◽  
Vol 42 (1) ◽  
pp. 52-59 ◽  
Author(s):  
S N Raina ◽  
Y Mukai
Keyword(s):  
In Situ Hybridization ◽  
5S Rdna ◽  
Gene Families ◽  
Ribosomal Gene ◽  
Rrna Genes ◽  
Tetraploid Species ◽  
Arachis Species ◽  
26S Rdna ◽  
Rdna Loci

In order to obtain new information on the genome organization of Arachis ribosomal DNA, more particularly among A. hypogaea and its close relatives, the distribution of the 18S-5.8S-26S and 5S ribosomal RNA gene families on the chromosomes of 21 diploid and tetraploid Arachis species, selected from six of nine taxonomic sections, was analyzed by in situ hybridization with pTa71 (18S-5.8S-26S rDNA) and pTa794 (5S rDNA) clones. Two major 18S-5.8S-26S rDNA loci with intense signals were found in the nucleolus organizer regions (NOR) of each of the diploid and tetraploid species. In addition to extended signals at major NORs, two to six medium and (or) minute-sized signals were also observed. Variability in the number, size, and location of 18S-5.8S-26S sites could generally distinguish species within the same genome as well as between species with different genomes. The use of double fluorescence in situ hybridization enabled us to locate the positions of 5S rRNA genes in relation to the chromosomal location of 18S-5.8S-26S rRNA genes in Arachis chromosomes which were difficult to karyotype. Two or four 5S rDNA loci and 18S-5.8S-26S rDNA loci were generally located on different chromosomes. The tandemly repeated 5S rDNA sites were diagnostic for T and C genomes. In one species, each of B and Am genomes, the two ribosomal gene families were observed to occur at the same locus. Barring A. ipaensis and A. valida, all the diploid species had characteristic centromeric bands in all the 20 chromosomes. In tetraploid species A. hypogaea and A. monticola only 20 out of 40 chromosomes showed centromeric bands. Comparative studies of distribution of the two ribosomal gene families, and occurrence of centromeric bands in only 20 chromosomes of the tetraploid species suggests that A. villosa and A. ipaensis are the diploid progenitors of A. hypogaea and A. monticola. This study excludes A. batizocoi as the B genome donor species for A. hypogaea and A. monticola.Key words: Arachis species, 5S rRNA, 18S-5.8S-26S rRNA, in situ hybridization, evolution.

scholarly journals Intraspecific polymorphism of ribosomal DNA loci number and morphology in Brachypodium pinnatum and Brachypodium sylvaticum

2012 ◽  
Vol 17 (4) ◽  
Author(s):  
Ewa Breda ◽  
Elzbieta Wolny ◽  
Robert Hasterok
Keyword(s):  
5S Rdna ◽  
Staining Technique ◽  
Rdna Locus ◽  
Chromosomal Distribution ◽  
Metaphase Chromosomes ◽  
Brachypodium Sylvaticum ◽  
Rdna Sites ◽  
Rdna Loci ◽  
35S Rdna ◽  
25S Rdna

AbstractThe genus Brachypodium has become the target of extensive cytomolecular studies since one of its representatives, B. distachyon, has been accepted as a model plant for temperate cereals and forage grasses. Recent preliminary studies suggested that intraspecific rDNA polymorphism can occur in at least two members of the genus, B. sylvaticum and B. pinnatum, so the aim of this study was to further analyse this phenomenon. FISH with 25S rDNA and 5S rDNA probes was performed on somatic metaphase chromosomes, supplemented by the silver staining technique which distinguishes transcriptionally active from inactive 18S-5.8S-25S rDNA loci. The number, size and chromosomal distribution of 5S rDNA loci were very constant: two loci were invariably observed in all studied diploid accessions of both species, while four 5S rDNA loci were present in the tetraploid B. pinnatum. In contrast to 5S rDNA loci, those of the 35S rDNA were more variable. Two or three loci were observed in the diploid B. pinnatum and four in tetraploid accessions. In chromosome complements of B. sylvaticum accessions from two to six 35S rDNA sites were detected. Regardless of total rDNA locus number, only two were transcriptionally active in diploid accessions of both species, while two or four were active in the tetraploid B. pinnatum. Additionally, the fluorescent CMA/DAPI banding method was used to identify the relation between rDNA sites and CMA+ bands. It was revealed that the number and chromosomal distribution of CMA+ bands are in congruence only with 35S rDNA loci which gave strong FISH signals.

scholarly journals Karyotype characterization of Mugil incilis Hancock, 1830 (Mugiliformes: Mugilidae), including a description of an unusual co-localization of major and minor ribosomal genes in the family

2011 ◽  
Vol 9 (1) ◽  
pp. 107-112 ◽  
Author(s):  
Anne Kathrin Hett ◽  
Mauro Nirchio ◽  
Claudio Oliveira ◽  
Zoila Raquel Siccha ◽  
Anna Rita Rossi ◽  
...  
Keyword(s):  
Chromosome Pair ◽  
Chromosome Complement ◽  
5S Rdna ◽  
Gene Clusters ◽  
Ribosomal Genes ◽  
Nucleolus Organizer ◽  
The Family ◽  
Pair Number ◽  
Mugil Incilis ◽  
Secondary Constrictions

This study reports the description of the karyotype of Mugil incilis from Venezuela. The chromosome complement is composed of 48 acrocentric chromosomes, which uniformly decrease in size. Therefore, the homologues can not be clearly identified, with the exception of one of the largest chromosome pairs, classified as number 1, whose homologues may show a subcentromeric secondary constriction, and of chromosome pair number 24, which is considerably smaller than the others. C-banding showed heterochromatic blocks at the centromeric/pericentromeric regions of all chromosomes, which were more conspicuous on chromosomes 1, given the C-positive signals include the secondary constrictions. AgNO3 and fluorescent in situ hybridization (FISH) with 45S rDNA demonstrated that the nucleolus organizer regions are indeed located on the secondary constrictions of chromosome pair number 1. FISH with 5S rDNA revealed that the minor ribosomal genes are located on this same chromosome pair, near the NORs, though signals are closer to the centromeres and of smaller size, compared to those of the major ribosomal gene clusters. This is the first description of co-localization of major and minor ribosomal genes in the family. Data are discussed from a cytotaxonomic and phylogenetic perspective.

Comparative chromosomal localization of 45S and 5S rDNAs and implications for genome evolution in Cucumis

Genome ◽  
2016 ◽  
Vol 59 (7) ◽  
pp. 449-457 ◽  
Author(s):  
Zhen-Tao Zhang ◽  
Shu-Qiong Yang ◽  
Zi-Ang Li ◽  
Yun-Xia Zhang ◽  
Yun-Zhu Wang ◽  
...  
Keyword(s):  
Chromosomal Localization ◽  
5S Rdna ◽  
Chromosome Analysis ◽  
45S Rdna ◽  
Evolutionary Patterns ◽  
Site Number ◽  
Rdna Sites ◽  
Wild Accessions ◽  
Ribosomal Dnas

Ribosomal DNAs are useful cytogenetic markers for chromosome analysis. Studies investigating site numbers and distributions of rDNAs have provided important information for elucidating genome organization and chromosomal relationships of many species by fluorescence in situ hybridization. But relevant studies are scarce for species of the genus Cucumis, especially in wild species. In the present study, FISH was conducted to investigate the organization of 45S and 5S rDNA among 20 Cucumis accessions, including cultivars and wild accessions. Our results showed that the number of 45S rDNA sites varied from one to five pairs in different accessions, and most of these sites are located at the terminal regions of chromosomes. Interestingly, up to five pairs of 45S rDNA sites were observed in C. sativus var. sativus, the species which has the lowest chromosome number, i.e., 2n = 14. Only one pair of 5S rDNA sites was detected in all accessions, except for C. heptadactylus, C. sp, and C. spp that had two pairs of 5S rDNA sites. The distributions of 5S rDNA sites showed more variation than 45S rDNA sites. The phylogenetic analysis in this study showed that 45S and 5S rDNA have contrasting evolutionary patterns. We find that 5S rDNA has a polyploidization-related tendency towards the terminal location from an interstitial location but maintains a conserved site number, whereas the 45S rDNA showed a trend of increasing site number but a relatively conserved location.

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