Chromosomal evolution and distribution of telomeric repeats in golden moles (Chrysochloridae, Mammalia)

2008 ◽  
Vol 121 (2) ◽  
pp. 110-119 ◽  
Author(s):  
C. Gilbert ◽  
S. Maree ◽  
T.J. Robinson
Keyword(s):  
Chromosomal Evolution ◽  
Telomeric Repeats

Extensive Amplification of Telomeric Repeats in the Karyotypically Highly Diverse African Pygmy Mice

2017 ◽  
Vol 152 (2) ◽  
pp. 55-64 ◽  
Author(s):  
Victor Colomina ◽  
Josette Catalan ◽  
Janice Britton-Davidian ◽  
Frédéric Veyrunes
Keyword(s):  
Mammalian Species ◽  
Chromosomal Rearrangements ◽  
Replication Timing ◽  
Pericentromeric Region ◽  
Chromosomal Evolution ◽  
Telomeric Repeats ◽  
Telomeric Sequences ◽  
Interstitial Telomeric Sequences ◽  
Karyotypic Diversity ◽  
The One

Telomeres are ribonucleoprotein structures protecting the physical ends of eukaryotic chromosomes. However, telomeric sequences can also occur at non-terminal regions of chromosomes, forming the so-called interstitial telomeric sequences (ITSs). Some ITSs are considered as relics of past chromosomal rearrangements and as such provide important insights into karyotype evolution. By FISH, we explored the distribution of telomeric motifs in the genome of a complex of mammalian species that has long been recognized for its extraordinary karyotypic diversity: the African pygmy mice. This survey involved 5 species, representing 10 highly diverse karyotypes with or without autosomal and sex-autosome robertsonian (Rb) fusions. The study revealed that in species with an ancestral-like karyotype (i.e., no fusions; Mus mattheyi and M. indutus), only terminal telomeres were observed, whereas in species experiencing intense chromosomal evolution (e.g., M. minutoides, M. musculoides), a large amplification of telomeric repeats was also identified in the pericentromeric region of acrocentrics and most metacentrics. We concluded that (i) the mechanism of Rb fusion in the African pygmy mice is different than the one highlighted in the house mouse; (ii) the intensity of the ITS hybridization signal could be a signature of the age of formation of the Rb fusion; (iii) the large amplification of pericentromeric telomeric sequences in acrocentrics may mediate the formation of Rb fusions, and (iv) the ITSs on the sex-autosome fusion Rb(X.1) may participate to the insulation buffer between the sexual and autosomal arms to prevent X inactivation from spreading and silencing autosomal genes and allow the independent regulation of replication timing of both segments.

scholarly journals Microsatellite and Chromosome Evolution of Parthenogenetic Sitobion Aphids in Australia

Genetics ◽  
1996 ◽  
Vol 144 (2) ◽  
pp. 747-756 ◽  
Author(s):  
Paul Sunnucks ◽  
Phillip R England ◽  
Andrea C Taylor ◽  
Dinah F Hales
Keyword(s):  
Sexual Reproduction ◽  
Chromosome Evolution ◽  
Genetic Recombination ◽  
Allelic Variation ◽  
Repeat Unit ◽  
Chromosomal Evolution ◽  
Microsatellite Variation ◽  
Wide Range ◽  
Sexual Recombination ◽  
Minimum Numbers

Abstract Single-locus microsatellite variation correlated perfectly with chromosome number in Sitobion miscanthi aphids. The microsatellites were highly heterozygous, with up to 10 alleles per locus in this species. Despite this considerable allelic variation, only seven different S. miscanthi genotypes were discovered in 555 individuals collected from a wide range of locations, hosts and sampling periods. Relatedness between genotypes suggests only two successful colonizations of Australia. There was no evidence for genetic recombination in 555 S. miscanthi so the occurrence of recent sexual reproduction must be near zero. Thus diversification is by mutation and chromosomal rearrangement alone. Since the aphids showed no sexual recombination, microsatellites can mutate without meiosis. Five of seven microsatellite differences were a single repeat unit, and one larger jump is likely. The minimum numbers of changes between karyotypes corresponded roughly one-to-one with microsatellite allele changes, which suggests very rapid chromosomal evolution. A chromosomal fission occurred in a cultured line, and a previously unknown chromosomal race was detected. All 121 diverse S. near fragariae were heterozygous but revealed only one genotype. This species too must have a low rate of sexual reproduction and few colonizations of Australia.

scholarly journals Chromosomal painting of the sandpiper (Actitis macularius) detects several fissions for the Scolopacidae family (Charadriiformes)

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Melquizedec Luiz Silva Pinheiro ◽  
Cleusa Yoshiko Nagamachi ◽  
Talita Fernanda Augusto Ribas ◽  
Cristovam Guerreiro Diniz ◽  
Patricia Caroline Mary O´Brien ◽  
...  
Keyword(s):  
Chromosome Painting ◽  
Diploid Number ◽  
Chromosomal Evolution ◽  
Long Distance ◽  
Chromosomal Painting ◽  
Cytogenetic Studies ◽  
Burhinus Oedicnemus ◽  
Clear Idea ◽  
First Time

Abstract Background The Scolopacidae family (Suborder Scolopaci, Charadriiformes) is composed of sandpipers and snipes; these birds are long-distance migrants that show great diversity in their behavior and habitat use. Cytogenetic studies in the Scolopacidae family show the highest diploid numbers for order Charadriiformes. This work analyzes for the first time the karyotype of Actitis macularius by classic cytogenetics and chromosome painting. Results The species has a diploid number of 92, composed mostly of telocentric pairs. This high 2n is greater than the proposed 80 for the avian ancestral putative karyotype (a common feature among Scolopaci), suggesting that fission rearrangements have formed smaller macrochromosomes and microchromosomes. Fluorescence in situ hybridization using Burhinus oedicnemus whole chromosome probes confirmed the fissions in pairs 1, 2, 3, 4 and 6 of macrochromosomes. Conclusion Comparative analysis with other species of Charadriiformes studied by chromosome painting together with the molecular phylogenies for the order allowed us to raise hypotheses about the chromosomal evolution in suborder Scolopaci. From this, we can establish a clear idea of how chromosomal evolution occurred in this suborder.

scholarly journals Cytogenetic Analysis of the Asian Box Turtles of the Genus Cuora (Testudines, Geoemydidae)

Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 156
Author(s):  
Lorenzo Clemente ◽  
Sofia Mazzoleni ◽  
Eleonora Pensabene ◽  
Tomáš Protiva ◽  
Philipp Wagner ◽  
...  
Keyword(s):  
Sex Determination ◽  
Sex Chromosomes ◽  
Wide Distribution ◽  
Iucn Red List ◽  
Telomeric Repeats ◽  
Rdna Loci ◽  
Box Turtles ◽  
Genotypic Sex Determination ◽  
Poorly Differentiated ◽  
Almost All

The Asian box turtle genus Cuora currently comprises 13 species with a wide distribution in Southeast Asia, including China and the islands of Indonesia and Philippines. The populations of these species are rapidly declining due to human pressure, including pollution, habitat loss, and harvesting for food consumption. Notably, the IUCN Red List identifies almost all species of the genus Cuora as Endangered (EN) or Critically Endangered (CR). In this study, we explore the karyotypes of 10 Cuora species with conventional (Giemsa staining, C-banding, karyogram reconstruction) and molecular cytogenetic methods (in situ hybridization with probes for rDNA loci and telomeric repeats). Our study reveals a diploid chromosome number of 2n = 52 chromosomes in all studied species, with karyotypes of similar chromosomal morphology. In all examined species, rDNA loci are detected at a single medium-sized chromosome pair and the telomeric repeats are restricted to the expected terminal position across all chromosomes. In contrast to a previous report, sex chromosomes are neither detected in Cuoragalbinifrons nor in any other species. Therefore, we assume that these turtles have either environmental sex determination or genotypic sex determination with poorly differentiated sex chromosomes. The conservation of genome organization could explain the numerous observed cases of interspecific hybridization both within the genus Cuora and across geoemydid turtles.

scholarly journals Finding of novel telomeric repeats and their distribution in the human genome

Genomics ◽  
2020 ◽  
Vol 112 (5) ◽  
pp. 3565-3570
Author(s):  
Sathyalakshmi Alaguponniah ◽  
Deepa Velayudhan Krishna ◽  
Sayan Paul ◽  
Johnson Retnaraj Samuel Selvan Christyraj ◽  
Krishnan Nallaperumal ◽  
...  
Keyword(s):  
Human Genome ◽  
Telomeric Repeats

scholarly journals Chromosomal location of Ag/CMA3-NORs, 5S rDNA and telomeric repeats in two stickleback species

2011 ◽  
Vol 78 (1) ◽  
pp. 12-19 ◽  
Author(s):  
K. Ocalewicz ◽  
P. Woznicki ◽  
G. Furgala-Selezniow ◽  
M. Jankun
Keyword(s):  
Chromosomal Location ◽  
5S Rdna ◽  
Telomeric Repeats

scholarly journals Xenopus Cytogenetics and Chromosomal Evolution

2015 ◽  
Vol 145 (3-4) ◽  
pp. 192-200 ◽  
Author(s):  
Vladimir Krylov ◽  
Tereza Tlapakova
Keyword(s):  
Developmental Biology ◽  
Genetic Linkage ◽  
Chromosome Banding ◽  
Chromosomal Evolution ◽  
Model Organisms ◽  
Gene Localization ◽  
Physical Maps ◽  
Gene Position ◽  
Tightly Coupled

The genus Xenopus represents important model organisms in the field of developmental biology and chromosomal evolution. Developmental processes are tightly coupled with the analysis of gene function via genetic linkage and mapping. Cytogenetic techniques such as chromosome banding or FISH are essential tools for the determination of gene position and subsequently for the construction of linkage and physical maps. Here, we present a summary of key achievements in X. tropicalis and X. laevis cytogenetics with emphasis on the gene localization to chromosomes. The second part of this review is focused on the chromosomal evolution regarding both above-mentioned species. With respect to methodology, hybridization techniques such as FISH and chromosome-specific painting FISH are highlighted.

Diversity and Karyotypic Evolution in the Genus Neacomys (Rodentia, Sigmodontinae)

2015 ◽  
Vol 146 (4) ◽  
pp. 296-305 ◽  
Author(s):  
Willam O. da Silva ◽  
Julio C. Pieczarka ◽  
Rogério V. Rossi ◽  
Horacio Schneider ◽  
Iracilda Sampaio ◽  
...  
Keyword(s):  
Molecular Phylogeny ◽  
Diploid Number ◽  
Constitutive Heterochromatin ◽  
Chromosomal Evolution ◽  
The Other ◽  
Karyotypic Evolution ◽  
Drastic Reduction ◽  
Ancestral Species ◽  
Pericentric Inversions ◽  
Amazonian Region

Neacomys (Sigmodontinae) comprises 8 species mainly found in the Amazonian region. We describe 5 new karyotypes from Brazilian Amazonia: 2 cytotypes for N. paracou (2n = 56/FNa = 62-66), 1 for N. dubosti (2n = 64/FNa = 68), and 2 for Neacomys sp. (2n = 58/FNa = 64-70), with differences in the 18S rDNA. Telomeric probes did not show ITS. We provide a phylogeny using Cytb, and the analysis suggests that 2n = 56 with a high FNa is ancestral for the genus, as found in N. paracou, being retained by the ancestral forms of the other species, with an increase in 2n occurring independently in N. spinosus and N. dubosti. Alternatively, an increase in 2n may have occurred in the ancestral taxon of the other species, followed by independent 2n-reduction events in Neacomys sp. and in the ancestral species of N. tenuipes, N. guianae, N. musseri, and N. minutus. Finally, a drastic reduction event in the diploid number occurred in the ancestral species of N. musseri and N. minutus which exhibit the lowest 2n of the genus. The karyotypic variations found in both intra- and interspecific samples, associated with the molecular phylogeny, suggest a chromosomal evolution with amplification/deletion of constitutive heterochromatin and rearrangements including fusions, fissions, and pericentric inversions.

scholarly journals Rates and Patterns of Chromosomal Evolution inDrosophila pseudoobscuraandD. miranda

Genetics ◽  
2006 ◽  
Vol 173 (2) ◽  
pp. 779-791 ◽  
Author(s):  
Carolina Bartolomé ◽  
Brian Charlesworth
Keyword(s):  
Chromosomal Evolution
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