The contrasting role of heterochromatin in the differentiation of sex chromosomes: an overview from Neotropical fishes

Autor(es)

Cioffi, M. B. ^[1] ; Moreira-Filho, O. ^[1] ; Almeida-Toledo, L. F. ^[2] ; Bertollo, L. A. C. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Carlos, Dept Genet & Evolucao, BR-13560 Sao Carlos, SP - Brazil

^[2] Univ Sao Paulo, Inst Biociencias, Dept Biol, Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Fish Biology; v. 80, n. 6, p. 2125-2139, MAY 2012.
• Citações Web of Science: 17
• Assunto(s): Cromossomos sexuais Characidae Peixes Cromossomo X

Resumo

During the evolutionary process of the sex chromosomes, a general principle that arises is that cessation or a partial restriction of recombination between the sex chromosome pair is necessary. Data from phylogenetically distinct organisms reveal that this phenomenon is frequently associated with the accumulation of heterochromatin in the sex chromosomes. Fish species emerge as excellent models to study this phenomenon because they have much younger sex chromosomes compared to higher vertebrates and many other organisms making it possible to follow their steps of differentiation. In several Neotropical fish species, the heterochromatinization, accompanied by amplification of tandem repeats, represents an important step in the morphological differentiation of simple sex chromosome systems, especially in the ZZ/ZW sex systems. In contrast, multiple sex chromosome systems have no additional increase of heterochromatin in the chromosomes. Thus, the initial stage of differentiation of the multiple sex chromosome systems seems to be associated with proper chromosomal rearrangements, whereas the simple sex chromosome systems have an accumulation of heterochromatin. In this review, attention has been drawn to this contrasting role of heterochromatin in the differentiation of simple and multiple sex chromosomes of Neotropical fishes, highlighting their surprising evolutionary dynamism. (AU)

• Processo FAPESP: 09/14881-3 - Evolução cromossômica na família Erythrinidae: mapeamento citogenético de DNAs repetitivos e microdissecção de cromossomos sexuais
• Beneficiário: Marcelo de Bello Cioffi
• Modalidade de apoio: Bolsas no Brasil - Doutorado