chromosomal differentiation
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2021 ◽  
Vol 12 ◽  
Author(s):  
María Laura González ◽  
Jorge Oscar Chiapella ◽  
Juan Domingo Urdampilleta

Diverse families of satellite DNA (satDNA) were detected in heterochromatin regions of Deschampsia. This kind of repetitive DNA consists of tandem repeat sequences forming big arrays in genomes, and can contribute to lineages differentiation. The differentiation between types of satDNA is related to their sequence identity, the size and number of monomers forming the array, and their chromosomal location. In this work, four families of satDNA (D2, D3, D12, D13), previously isolated by genomic analysis, were studied on chromosomal preparations of 12 species of Deschampsia (D. airiformis, D. antarctica, D. cespitosa, D. cordillerarum, D. elongata, D. kingii, D. laxa, D. mendocina, D. parvula, D. patula, D. venustula, and Deschampsia sp) and one of Deyeuxia (D. eminens). Despite the number of satDNA loci showing interspecific variation, the general distribution pattern of each satDNA family is maintained. The four satDNA families are AT-rich and associated with DAPI + heterochromatin regions. D2, D3, and D12 have mainly subterminal distribution, while D13 is distributed in intercalary regions. Such conservation of satDNA patterns suggests a not random distribution in genomes, where the variation between species is mainly associated with the array size and the loci number. The presence of satDNA in all species studied suggests a low genetic differentiation of sequences. On the other hand, the variation of the distribution pattern of satDNA has no clear association with phylogeny. This may be related to high differential amplification and contraction of sequences between lineages, as explained by the library model.


2021 ◽  
pp. 1-9
Author(s):  
Masamichi Kuroda ◽  
Kiko Shibata ◽  
Takafumi Fujimoto ◽  
Masaru Murakami ◽  
Etsuro Yamaha ◽  
...  

In dojo loach (<i>Misgurnus anguillicaudatus</i>), although most wild types are gonochoristic diploids that are genetically differentiated into 2 groups, A and B, clonal lineages appear in certain localities. Clonal loaches have been considered to have hybrid origins between the 2 groups by a series of genetic studies. In this study, using FISH with a newly developed probe (ManDra-A), we identified 26 (1 pair of metacentric and 12 pairs of telocentric chromosomes) of 50 diploid chromosomes in contemporary wild-type group A loach. In contrast, ManDra-A signals were not detected on metacentric chromosomes derived from the ancestral group A of clonal loach. The FISH results clearly showed the presence of certain differentiations in metacentric chromosomes between ancestral and contemporary group A loach. Two-color FISH with ManDra-A and group B-specific ManDra (renamed ManDra-B) probes reconfirmed the hybrid origin of clones by identifying chromosomes from both groups A and B in metaphases. Our results showed the hybrid origin of clonally reproducing fish and the possibility that chromosomal differentiation between ancestral and contemporary fish can affect gametogenesis. In meiotic spermatocytes of sex-reversed clones, ManDra-A, and not ManDra-B, signals were detected in 12 out of 50 bivalents. Thus, the results further support the previous conclusion that clonal gametogenesis was assured by pairing between sister chromosomes duplicated from each ancestral chromosome from group A or B. Our study deepens the knowledge about the association between clonality and hybridity in unisexual vertebrates.


Genes ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 270 ◽  
Author(s):  
Francisca Garcia ◽  
Luis Biedma ◽  
Javier Calzada ◽  
Jacinto Román ◽  
Alberto Lozano ◽  
...  

The genus Crocidura represents a remarkable model for the study of chromosome evolution. This is the case of the lesser white-toothed shrew (Crocidura suaveolens), a representative of the Palearctic group. Although continuously distributed from Siberia to Central Europe, C. suaveolens is a rare, habitat-specialist species in the southwesternmost limit of its distributional range, in the Gulf of Cádiz (Iberian Peninsula). In this area, C. suaveolens is restricted to genetically isolated populations associated to the tidal marches of five rivers (Guadiana, Piedras, Odiel, Tinto and Guadalquivir). This particular distributional range provides a unique opportunity to investigate whether genetic differentiation and habitat specialization was accompanied by chromosomal variation. In this context, the main objective of this study was to determinate the chromosomal characteristics of the habitat-specialist C. suaveolens in Southwestern Iberia, as a way to understand the evolutionary history of this species in the Iberian Peninsula. A total of 41 individuals from six different populations across the Gulf of Cádiz were collected and cytogenetically characterized. We detected four different karyotypes, with diploid numbers (2n) ranging from 2n = 40 to 2n = 43. Two of them (2n = 41 and 2n = 43) were characterized by the presence of B-chromosomes. The analysis of karyotype distribution across lineages and populations revealed an association between mtDNA population divergence and chromosomal differentiation. C. suaveolens populations in the Gulf of Cádiz provide a rare example of true karyotypic polymorphism potentially associated to genetic isolation and habitat specialization in which to investigate the evolutionary significance of chromosomal variation in mammals and their contribution to phenotypic and ecological divergence.


2019 ◽  
pp. 134-185
Author(s):  
Nina S. Bulatova ◽  
Larisa S. Biltueva ◽  
Svetlana V. Pavlova ◽  
Natalia S. Zhdanova ◽  
Jan Zima

Zebrafish ◽  
2019 ◽  
Vol 16 (1) ◽  
pp. 87-97 ◽  
Author(s):  
Mariana Campaner Usso ◽  
Angélica Rossotti dos Santos ◽  
Juceli Gonzalez Gouveia ◽  
Wilson Frantine-Silva ◽  
Cristian Araya-Jaime ◽  
...  

2017 ◽  
Vol 81 (6) ◽  
pp. 234-248 ◽  
Author(s):  
Inam Ullah ◽  
Jill K. Olofsson ◽  
Ashot Margaryan ◽  
Melissa Ilardo ◽  
Habib Ahmad ◽  
...  

2014 ◽  
Vol 301 (5) ◽  
pp. 1325-1334 ◽  
Author(s):  
Juan D. Urdampilleta ◽  
Franco Chiarini ◽  
Laura Stiefkens ◽  
Gabriel Bernardello

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Paulo Roberto Antunes de Mello Affonso ◽  
Maria Aparecida Fernandes ◽  
Josivanda Santos Almeida ◽  
Wagner Franco Molina

Surgeonfishes are a species-rich group and a major biomass on coral reefs. Three species are commonly found throughout South Atlantic,Acanthurus bahianus,A. chirurgus, andA. coeruleus. In this paper, we present the first cytogenetic data of these species, revealing a sequential chromosomal diversification.A. coeruleuswas characterized by a relatively conserved karyotype evolved by pericentric inversions of some pairs (2n=48, 2sm + 4st + 42a). In contrast, the karyotypes ofA. bahianus(2n=36) andA. chirurgus(2n=34) were highly differentiated by the presence of six large metacentric pairs inA. bahianus(12m + 2sm + 4st + 18a) andA. chirurgus(12m + 2sm + 4st +1 6a) probably derived by chromosomal fusions that corroborate their closer relationship. A discerniblein tandemfusion represents an autapomorphic character toA. chirurgus. In spite of macrostructure variation, single nucleolar organizer regions (NORs) on short arms of a subtelocentric pair and similar distribution of C-bands were observed in the three species. Overlapping of chromosomal data with molecular phylogeny indicated pericentric inversions which took place nearly at 19 Ma while centric fusions are as recent as 5 Ma. A physical mapping of coding and noncoding sequences inAcanthuruscould clarify the role of additional rearrangements during their chromosomal evolution.


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