¹Departamento de Biología Experimental, Área de Genética, Universidad de Jaén, Jaén, Spain

Correspondence: Dr T Palomeque, Departamento de Biología Experimental, Área de Genética, Universidad de Jaén, Campus de las Lagunillas sn, Jaén 23071, Spain. E-mail: tpalome@ujaen.es

Received 15 May 2007; Revised 5 February 2008; Accepted 16 March 2008; Published online 16 April 2008.

Abstract

The study of insect satellite DNAs (satDNAs) indicates the evolutionary conservation of certain features despite their sequence heterogeneity. Such features can include total length, monomer length, motifs, particular regions and/or secondary and tertiary structures. satDNAs may act as protein-binding sites, structural domains or sites for epigenetic modifications. The selective constraints in the evolution of satDNAs may be due to the satDNA sequence interaction with specific proteins important in heterochromatin formation and possible a role in controlling gene expression. The transcription of satDNA has been described in vertebrates, invertebrates and plants. In insects, differential satDNA expression has been observed in different cells, developmental stages, sex and caste of the individuals. These transcription differences may suggest their involvement in gene-regulation processes. In addition, the satDNA or its transcripts appear to be involved in heterochromatin formation and in chromatin-elimination processes. The importance of transposable elements to insect satDNA is shown by their presence as a constituent of satDNA in several species of insects (including possible active elements). In addition, they may be involved in the formation of centromeres and telomeres and in the homogenization and expansion of satDNA.