Chromosomal Mapping of Repetitive DNAs in Triportheus trifurcatus Characidae, Characiformes: Insights into the Differentiation of the Z and W ChromosomesReport as inadecuate




Chromosomal Mapping of Repetitive DNAs in Triportheus trifurcatus Characidae, Characiformes: Insights into the Differentiation of the Z and W Chromosomes - Download this document for free, or read online. Document in PDF available to download.

Repetitive DNA sequences play an important role in the structural and functional organization of chromosomes, especially in sex chromosome differentiation. The genus Triportheus represents an interesting model for such studies because all of its species analyzed so far contain a ZZ-ZW sex chromosome system. A close relationship has been found between the differentiation of the W chromosome and heterochromatinization, with the involvement of different types of repetitive DNA in this process. This study investigated several aspects of this association in the W chromosome of Triportheus trifurcatus 2n = 52 chromosomes, including the cytogenetic mapping of repetitive DNAs such as telomeric sequences TTAGGGn, microsatellites and retrotransposons. A remarkable heterochromatic segment on the W chromosome was observed with a preferential accumulation of CAC10, CAG10, CGG10, GAA10 and TA15. The retrotransposons Rex1 and Rex3 showed a general distribution pattern in the chromosomes, and Rex6 showed a different distribution on the W chromosome. The telomeric repeat TTAGGGn was highly evident in both telomeres of all chromosomes without the occurrence of ITS. Thus, the differentiation of the W chromosome of T. trifurcatus is clearly associated with the formation of heterochromatin and different types of repetitive DNA, suggesting that these elements had a prominent role in this evolutionary process.



Author: Cassia Fernanda Yano, Juliana Poltronieri, Luiz Antonio Carlos Bertollo, Roberto Ferreira Artoni, Thomas Liehr, Marcelo de Bello

Source: http://plos.srce.hr/



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