Conserved and variable domains in satellite DNAs of mitotic parthenogenetic root-knot nematode species Nevenka Meštrović a , Onivaldo Randig b,1 , Pierre Abad b , Miroslav Plohl a, ⁎ , Philippe Castagnone-Sereno b a Ruđer Bošković Institute, Bijenička 54, HR-10000 Zagreb, Croatia b INRA, UMR 1064 IPMSV, 400 Route des Chappes, BP167, 06903 Sophia Antipolis Cedex, France Received 20 May 2005; received in revised form 28 June 2005; accepted 19 July 2005 Received by D. Fitch Available online 17 October 2005 Abstract Two satellite DNAs have been characterized in the mitotic parthenogenetic root-knot nematodes Meloidogyne javanica and M. paranaensis, agriculturally important phytoparasitic species. The satellite repeat variants cloned from M. javanica could not be resolved from those described earlier in M. arenaria [Castagnone-Sereno, P., Leroy, F., Abad, P., 2000. Cloning and characterization of an extremely conserved satellite DNA family from the root-knot nematode Meloidogyne arenaria. Genome 43, 346–353] and are therefore classified as a single satellite named MARJA. However, this satellite shows 34.3% sequence divergence in comparison with the MPA1 satellite characterized in M. paranaensis, and monomer variants of both satellites are clearly distinguished by homogenized nucleotide substitutions. Nucleotide variability analysis revealed in one segment of the satellite monomer domains of high and low variability, conserved both within and between monomer variants of the two satellites. Intersatellite conservation of these domains indicates evolution of satellite sequence under different constraints, probably due to some functional interactions. In addition, high intrasatellite homogeneity, presence of ancestral mutations in groups of MARJA monomers in both M. javanica and M. arenaria and highly homogenized divergent positions in comparison with the MPA1 indicate similar sequence dynamics in mitotic parthenogenetic taxa to that observed in amphimictic species. © 2005 Elsevier B.V. All rights reserved. Keywords: Tandem repeats; Variability analysis; Concerted evolution; Homogenization; Meloidogyne 1. Introduction Tandemly repeated, highly abundant non-coding sequences or satellite DNAs represent a major component of heterochro- matic portions of chromosomes, including functional centro- meres (e.g. Sun et al., 2003), but no sequence-specific role has been definitively established. It can be assumed that functional sequence elements, if they exist within a satellite, should evolve under constraints which would affect distri- bution of mutations among monomer sequence variants. However, studies of influence of selection on satellite DNAs are scarce and concentrated mostly on the human α-satellite and the centromeric satellite from Arabidopsis thaliana (Romanova et al., 1996; Heslop-Harrison et al., 1999). A recent large-scale survey undoubtly shows nonuniformity in the rate of evolution along the monomer sequence of these two repetitive DNAs, interpreted as a consequence of interactions of DNA-binding proteins with the satellite DNA (Hall et al., 2003). Alternatively, functional constraints on some satellite DNAs might be acting to maintain higher-order structures and satellite monomer length (Plohl et al., 1998; Rojas-Rousse et al., 1993). Gene 362 (2005) 44 – 50 www.elsevier.com/locate/gene Abbreviations: bp, base pairs; PCR, polymerase chain reaction; CENP-B box, centromeric protein-B box; EDTA, ethylenediaminetetraacetic acid; SDS, sodium dodecyl sulphate; SSC, 0.15 M NaCl/0.0015 M Na 3 citrate pH 7.6; RKN, root-knot nematode(s); hLRT, hierarchical likelihood test; NJ, Neighbor- Joining; SD, standard deviation. ⁎ Corresponding author. Ruđer Bošković Institute, Bijenička 54, HR-10002 Zagreb, Croatia. Tel.: +385 1 4561 083; fax: +385 1 4561 177. E-mail address: plohl@irb.hr (M. Plohl). 1 Current address: CNPq - CGAPB, SPEN 509, Bloco A, Ed. Nazir I, 70750- 501, Brasilia, DF, Brazil. 0378-1119/$ - see front matter © 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.gene.2005.07.033