The involvement of repetitive sequences in the remodelling of karyotypes: The Phodopus genomes (Rodentia, Cricetidae)

Paço, Ana; Chaves, Raquel; Vieira-da-Silva, A.; Adega, Filomena

doi:10.1016/j.micron.2012.11.010

Cited by 26 publications

(32 citation statements)

References 52 publications

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“…1), as previously reported for G. maculata [Matoso Silva et al, 2016]. The finding of numerous ITSs in a second gen- et species of an older lineage than G. maculata [Gaubert et al, 2004b], together with the known instability of ITSs [Rogatcheva et al, 2000;Ruiz-Herrera et al, 2008;Paço et al, 2013], are consistent with the hypothesis that the observed ITSs are remnants of extensive chromosomal rearrangements involving telomeric regions [Meyne et al, 1990;Slijepcevic, 1998;Ruiz-Herrera et al, 2008;Mazzoleni et al, 2017] that have occurred in the lineage leading to Genetta [Matoso Silva et al, 2016]. Some of these (peri)centromeric ITSs were detected at the boundaries of adjacent painted segments, that is, at the breakpoint regions of the rearrangements that led to the current G. genetta chromosomes (e.g., GGE3, GGE4, GGE8, and GGE17; online suppl.…”

Section: Discussionsupporting

confidence: 78%

Comparative Chromosome Painting in Genets (Carnivora, Viverridae, Genetta), the Only Known Feliforms with a Highly Rearranged Karyotype

Adega¹,

Silva²,

Kjöllerström³

et al. 2018

Cytogenet Genome Res

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Mammalian carnivores have been extensively studied by cross-species chromosome painting, which indicated a high degree of karyotypic conservatism in the cat-like suborder Feliformia relative to the ancestral carnivore karyotype (ACK). The first exception to this high degree of karyotypic conservation in feliforms was recently confirmed in genets, mesocarnivores belonging to the basal family Viverridae. Here, we present a comparative analysis of the chromosome rearrangements among 2 subspecies of the small-spotted genet Genetta genetta (the Iberian nominate and the Arabian grantii) and the panther genet G. maculata, the 2 most common and widespread genets, using whole-chromosome paints from the domestic cat (Felis catus). The chromosome homology maps and the presence of numerous interstitial telomeric sites in both genet species strengthen the hypothesis that a highly rearranged karyotype compared to the ACK may occur throughout Genetta. The karyotype of G. maculata appears to have undergone more rearrangements than that of G. genetta, which is an older lineage. Notably, we identified a tandem fusion distinguishing G. g. genetta and G. g.grantii. As G. g. grantii is morphologically and genetically distinctive, and tandem fusions have been associated with substantial postzygotic isolation in mammals, this cytogenetic finding flags the subspecies for future taxonomic investigations.

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Section: Discussionsupporting

confidence: 78%

Comparative Chromosome Painting in Genets (Carnivora, Viverridae, Genetta), the Only Known Feliforms with a Highly Rearranged Karyotype

Adega¹,

Silva²,

Kjöllerström³

et al. 2018

Cytogenet Genome Res

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“…The data assembled allowed to propose a model for the origin and evolution of the studied repeats, revealing at the same time a link between these repeats and the chromosome evolution process in Phodopus. These Phodopus species present very divergent karyotypes in relation to the ancestral Muroidea (Romanenko et al 2007) and a high heterochromatic molecular heterogeneity (Paço et al 2013), which is indicative of a high molecular dynamics of the Phodopus repetitive fraction. The molecular dynamics of these repeats might have been the source for the evolutionary chromosome rearrangements that shaped these genomes.…”

Section: Introductionmentioning

confidence: 99%

The puzzling character of repetitive DNA in Phodopus genomes (Cricetidae, Rodentia)

et al. 2015

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Three novel repetitive DNA sequences are described, presenting a similar heterochromatic chromosomal location in two hamster species: Phodopus roborovskii and Phodopus sungorus (Cricetidae, Rodentia). Namely, two species-specific repetitive sequences (PROsat from P. roborovskii and PSUchr1sat from P. sungorus) surrounding a third one (PsatDNA), that is shared by both hamster genomes. Fiber-FISH analyses revealed that PROsat intermingles with PsatDNA in P. roborovskii and PSUchr1sat intermingles with PsatDNA in P. sungorus. A model explaining the evolution of this intricate chromosomal distribution is proposed, which can explain better the evolution of these very derivative genomes (in comparison to the ancestral Muroidea). The most plausible evolutionary scenario seems to be the expansion of a number of repeats into other's domain, most probably resulting in its intermingling, followed by the subsequent spread of these complex repeats from a single chromosomal location to other chromosomes. Evidences of an association between repetitive sequences and the chromosome evolution process were observed, namely for PROsat. Most probably, the evolutionary breakpoints that shaped PRO and PSU chromosomes (pericentric inversions and fusions) occurred within the boundaries of PROsat blocks in the ancestor. The repeats high diversity at the heterochromatic regions of Phodopus chromosomes, together with its complex organization, suggests that these species are important models for evolutionary studies, namely in the investigation of a possible relationship between repetitive sequences and the occurrence of chromosomal rearrangements and consequently, in genome evolution.

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“…Constitutive heterochromatin is an impediment to crossing-over (Stack, 1984) but also a preferable site of breakpoints that trigger chromosome structural changes (Paço et al, 2013 and the literature therein). Unfortunately, little is known about the distribution of constitutive heterochromatin and euchromatin on Oenothera chromosomes.…”

Section: Introductionmentioning

confidence: 99%

Translocations of Chromosome End-Segments and Facultative Heterochromatin Promote Meiotic Ring Formation in Evening Primroses

2014

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Due to reciprocal chromosomal translocations, many species of Oenothera (evening primrose) form permanent multichromosomal meiotic rings. However, regular bivalent pairing is also observed. Chiasmata are restricted to chromosomal ends, which makes homologous recombination virtually undetectable. Genetic diversity is achieved by changing linkage relations of chromosomes in rings and bivalents via hybridization and reciprocal translocations. Although the structural prerequisite for this system is enigmatic, whole-arm translocations are widely assumed to be the mechanistic driving force. We demonstrate that this prerequisite is genome compartmentation into two epigenetically defined chromatin fractions. The first one facultatively condenses in cycling cells into chromocenters negative both for histone H3 dimethylated at lysine 4 and for C-banding, and forms huge condensed middle chromosome regions on prophase chromosomes. Remarkably, it decondenses in differentiating cells. The second fraction is euchromatin confined to distal chromosome segments, positive for histone H3 lysine 4 dimethylation and for histone H3 lysine 27 trimethylation. The end-segments are deprived of canonical telomeres but capped with constitutive heterochromatin. This genomic organization promotes translocation breakpoints between the two chromatin fractions, thus facilitating exchanges of end-segments. We challenge the whole-arm translocation hypothesis by demonstrating why reciprocal translocations of chromosomal end-segments should strongly promote meiotic rings and evolution toward permanent translocation heterozygosity. Reshuffled endsegments, each possessing a major crossover hot spot, can furthermore explain meiotic compatibility between genomes with different translocation histories.

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The involvement of repetitive sequences in the remodelling of karyotypes: The Phodopus genomes (Rodentia, Cricetidae)

Cited by 26 publications

References 52 publications

Comparative Chromosome Painting in Genets (Carnivora, Viverridae, <b><i>Genetta</i></b>), the Only Known Feliforms with a Highly Rearranged Karyotype

Comparative Chromosome Painting in Genets (Carnivora, Viverridae, <b><i>Genetta</i></b>), the Only Known Feliforms with a Highly Rearranged Karyotype

The puzzling character of repetitive DNA in Phodopus genomes (Cricetidae, Rodentia)

Translocations of Chromosome End-Segments and Facultative Heterochromatin Promote Meiotic Ring Formation in Evening Primroses

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