Repetitive DNA in tropical tasar silkworm Antheraea mylitta Botlagunta Mahendran, Chitrangada Acharya, Rupesh Dash, Sudip K. Ghosh, S.C. Kundu ⁎ Department of Biotechnology, Indian Institute of Technology, Kharagpur 7213 02, India Received 19 May 2005; received in revised form 6 October 2005; accepted 4 November 2005 Available online 7 February 2006 Received by W. Makalowski Abstract Antheraea mylitta is an endemic insect species producing the world famous tasar silk. Its populations occupying different ecological and geographical regions show certain degree of phenotypic variability for which they are known as ‘eco-races’. In order to understand the genetic variability and phylogenetic relationship among the different eco-races we characterized a repetitive TaqI genomic DNA fragment as a genetic marker. The sequence analysis and Southern hybridization show the repetitive nature of TaqI DNA fragment, designated as A. mylitta TaqI family repeat, AmTFR. The PCR amplification of AmTFR reveals its presence in all the tested eco-races of tasar silkworm and some other silk producing insects. The AmTFR is evenly distributed in all 31 meiotic metaphase I chromosomes as observed by fluorescent in situ hybridization. The AmTFR based phylogenetic analysis of the eco-races is not congruent with the morphological variations and their geographical distribution. © 2005 Elsevier B.V. All rights reserved. Keywords: Silk moth; Antheraea mylitta; Repetitive DNA; Phylogeny; Chromosomes; FISH 1. Introduction Antheraea mylitta, a lepidopteran insect, produces tasar silk. This insect species, wild in nature and distributed in different geographical regions, shows variation in its phenotypic traits such as fecundity, voltinism, and cocoon weight, silk ratio and also in their host plant preference (Sinha et al., 1994). The populations of this species are called ‘eco-races’. They are wild and tropical in nature and are distributed in the Indian sub-continent between 60–88° longitude and 16–24° latitudes (Thangavelu and Sinha, 1992). There were 34 eco-races reported by Jolly et al. (1974), but at present only fifteen of the eco-races are available, though only nine are used for commercial purpose at present (Sengupta et al., 1993). For the characterization of its populations it is very much essential to develop a DNA marker system for identifying the genetic variability. Different molecular markers are available for the characterization of genetic diversity of Bombyx mori (Prasad et al., 2005), whereas very little attention has been paid to under- stand the genetic diversity of nonmulberry silks. The eukaryotic genome constitutes various types of repeated sequences (Ekes et al., 2004). The repetitive DNA sequences are organized in long tandem arrays and defined as satellite DNA (satDNA). The satDNA is a class of non-coding DNA, universally found in heterochromatin, pericentromeric and/or telomeric region in all eukaryotes (Feliciello et al., 2005, Char- lesworth et al., 1994). Repeated sequences are known to evolve faster than the rest of the genomes through a pattern of con- certed evolution, resulting from variant homogenization and fixation within genomes through a process known as molecular drive (Dover, 2002) as observed in coleopteran species (Mra- vinac et al., 2002). They show extreme diversity in sequence, copy number or both among closely related species and popu- lations in quantitative as well as qualitative sense (Luchetti et al., 2005; Ugarkovic and Plohl, 2002). They are exploited as molecular marker for discrimination of species and populations for phylogenetic studies e.g. as in Drosophila species (Kuhn et al., 2003; Kuhn and Sene, 2005), red flour beetle (Galian and Vogler, 2003), haplodiploid insects in the genus of Formica (Lorite et al., 2004). Gene 370 (2006) 51 – 57 www.elsevier.com/locate/gene Abbreviations: AmTFR, A. mylitta TaqI family repeat; AfTFR, A. frithi TaqI family repeat; satDNA, satellite DNA; MP, maximum parsimony; ML, maxi- mum likelihood; FISH, fluorescence in situ hybridization. ⁎ Corresponding author. Tel.: +91 3222 283764; fax: +91 3222 278433. E-mail address: kundu@hijli.iitkgp.ernet.in (S.C. Kundu). 0378-1119/$ - see front matter © 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.gene.2005.11.010