Junk DNA promotes sex chromosome evolution

Matsunaga, Sachihiro

doi:10.1038/hdy.2009.36

Cited by 22 publications

(18 citation statements)

References 14 publications

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“…It is well known that the Y or W sex chromosomes accumulate high quantities of distinct classes of repetitive DNAs due to the low frequency of recombination 1, 18, 19, 21, 57, 58 . In some species, it was shown that these repetitive sequences are involved in genetic degeneration, chromatin organization and regulation of expression 36, 57, 59 .…”

Section: Discussionmentioning

confidence: 99%

High-throughput analysis of the satellitome revealed enormous diversity of satellite DNAs in the neo-Y chromosome of the cricket Eneoptera surinamensis

Palacios-Gimenez

Dias

Lima

et al. 2017

Sci Rep

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Satellite DNAs (satDNAs) constitute large portion of eukaryote genomes, comprising non-protein-coding sequences tandemly repeated. They are mostly found in heterochromatic regions of chromosomes such as around centromere or near telomeres, in intercalary heterochromatin, and often in non-recombining segments of sex chromosomes. We examined the satellitome in the cricket Eneoptera surinamensis (2n = 9, neo-X1X2Y, males) to characterize the molecular evolution of its neo-sex chromosomes. To achieve this, we analyzed illumina reads using graph-based clustering and complementary analyses. We found an unusually high number of 45 families of satDNAs, ranging from 4 bp to 517 bp, accounting for about 14% of the genome and showing different modular structures and high diversity of arrays. FISH mapping revealed that satDNAs are located mostly in C-positive pericentromeric regions of the chromosomes. SatDNAs enrichment was also observed in the neo-sex chromosomes in comparison to autosomes. Especially astonishing accumulation of satDNAs loci was found in the highly differentiated neo-Y, including 39 satDNAs over-represented in this chromosome, which is the greatest satDNAs diversity yet reported for sex chromosomes. Our results suggest possible involvement of satDNAs in genome increasing and in molecular differentiation of the neo-sex chromosomes in this species, contributing to the understanding of sex chromosome composition and evolution in Orthoptera.

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Section: Discussionmentioning

confidence: 99%

High-throughput analysis of the satellitome revealed enormous diversity of satellite DNAs in the neo-Y chromosome of the cricket Eneoptera surinamensis

Palacios-Gimenez

Dias

Lima

et al. 2017

Sci Rep

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“…Because these sequences evolve faster than unique sequences and genes, they tend to colonize these new “ghost towns” and rapidly accumulate on the chromosomes [37,49]. Additionally, a parallel can also be traced to the evolution of the sex chromosomes, in which the “gene deserts” found in the sex-specific chromosomes (Y or W) serve as ideal niches for the long-term survival of these elements due to the weaker selection in these regions [50,51]. Similar events could also explain the strong accumulation of repeated DNA elements that was found in several chromosomes of C .…”

Section: Discussionmentioning

confidence: 99%

Genomic Organization of Repetitive DNA Elements and Its Implications for the Chromosomal Evolution of Channid Fishes (Actinopterygii, Perciformes)

et al. 2015

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Channid fishes, commonly referred to as “snakeheads”, are currently very important in Asian fishery and aquaculture due to the substantial decline in natural populations because of overexploitation. A large degree of chromosomal variation has been found in this family, mainly through the use of conventional cytogenetic investigations. In this study, we analyzed the karyotype structure and the distribution of 7 repetitive DNA sequences in several Channa species from different Thailand river basins. The aim of this study was to investigate the chromosomal differentiation among species and populations to improve upon the knowledge of its biodiversity and evolutionary history. Rearrangements, such as pericentric inversions, fusions and polyploidization, appear to be important events during the karyotypic evolution of this genus, resulting in the chromosomal diversity observed among the distinct species and even among populations of the same species. In addition, such variability is also increased by the genomic dynamism of repetitive elements, particularly by the differential distribution and accumulation of rDNA sequences on chromosomes. This marked diversity is likely linked to the lifestyle of the snakehead fishes and their population fragmentation, as already identified for other fish species. The karyotypic features highlight the biodiversity of the channid fishes and justify a taxonomic revision of the genus Channa, as well as of the Channidae family as a whole, as some nominal species may actually constitute species complexes.

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“…In particular, sex chromosomes are subjected to distinct evolutionary forces compared to autosomes, in which repetitive DNAs sequences preferentially accumulate. This accumulation represents, in some instances, the early steps of differentiation between sex chromosomes, most likely before gene degeneration (Steinemann et al 1993;Vítková et al 2007;Matsunaga 2009;Kaiser and Bachtrog 2010).…”

Section: Introductionmentioning

confidence: 99%

Repetitive DNA chromosomal organization in the cricket Cycloptiloides americanus: a case of the unusual X1X20 sex chromosome system in Orthoptera

Palacios-Gimenez

Cabral-de-Mello

2014

Mol Genet Genomics

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A common placement for most sex chromosomes that is involved in their evolutionary histories is the accumulation of distinct classes of repetitive DNAs. Here, with the aim of understanding the poorly studied repetitive DNA organization in crickets and its possible role in sex chromosome differentiation, we characterized the chromosomes of the cricket species Cycloptiloides americanus, a species with the remarkable presence of the unusual sex chromosome system X1X20♂/X1X1X2X2♀. For these proposes, we used C-banding and mapping through the fluorescence in situ hybridization of some repetitive DNAs. The C-banding and distribution of highly and moderately repetitive DNAs (C 0t-1 DNA) varied depending of the chromosome. The greater accumulation of repetitive DNAs in the X2 chromosome was evidenced. The microsatellites were spread along entire chromosomes, but (AG)10 and (TAA)10 were less enriched, mainly in the centromeric areas. Among the multigene families, the 18S rDNA was spread throughout almost all of the chromosomes, except for pair 5 and X2, while the U2 snDNA was placed exclusively in the largest chromosome. Finally, the 5S rDNA was exclusively located in the short arms of the sex chromosomes. The obtained data reinforce the importance of chromosomal dissociation and inversion as a primary evolutionary mechanism to generate neo-sex chromosomes in the species studied, followed by the repetitive DNAs accumulation. Moreover the exclusive placement of 5S rDNA in the sex chromosomes suggests the involvement of this sequence in sex chromosome recognition throughout meiosis and, consequently, their maintenance, in addition to their avoiding degeneration.

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Junk DNA promotes sex chromosome evolution

Cited by 22 publications

References 14 publications

High-throughput analysis of the satellitome revealed enormous diversity of satellite DNAs in the neo-Y chromosome of the cricket Eneoptera surinamensis

High-throughput analysis of the satellitome revealed enormous diversity of satellite DNAs in the neo-Y chromosome of the cricket Eneoptera surinamensis

Genomic Organization of Repetitive DNA Elements and Its Implications for the Chromosomal Evolution of Channid Fishes (Actinopterygii, Perciformes)

Repetitive DNA chromosomal organization in the cricket Cycloptiloides americanus: a case of the unusual X1X20 sex chromosome system in Orthoptera

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