Characterization of a species-specific satellite DNA family of Dolichopoda schiavazzii (Orthoptera, Rhaphidophoridae) cave crickets

Abstract

The satellite DNA family pDoP102 is species specific for the cave cricket Dolichopoda schiavazzii, an endemic species of mainland and insular Tuscany. It consists of numerous tandemly arranged repeats, 102 bp in length, and evolved most probably after cladogenesis of D. schiavazzii from the D. baccettii-aegilion group within the last 2.3 +/- 0.8 million years. A sequence comparison of 31 clones (53 repetition units) from three isolated populations reveals a very high degree of sequence homogeneity within the species with no evidence for any specific population features. This appears to be in contrast to the results of allozyme analyses which account for a relatively old evolutionary divergence of the Elba island population from the mainland ones. Since the assumption of actual gene flow and recent colonization is rejected, the observed sequence homogeneity is hypothesized to be maintained by recombination processes preventing fixation of newly introduced mutations on pDoP102 sequence clusters.

Patterns of gene flow and genetic structure in cave-dwelling crickets of the Tuscan endemic, Dolichopoda schiavazzii (Orthoptera, Rhaphidophoridae)

“…Interestingly, a number of the D. schiavazzii populations analysed in this study have also been investigated for a satellite DNA family specific to this cave cricket species. A sequence comparison of 31 clones from three isolated populations revealed a very high degree of sequence homogeneity within the species, with no evidence of any specific population feature (Bachmann et a!., 1994). This result appeared to contrast with the allozyme data, which revealed genetic differentiation among populations.…”

Comparative FISH analysis in five species of Eyprepocnemidine grasshoppers

“…Species-specific satDNA has been found in some cases, for example, the cave cricket Dolichopoda schiavazzii (Bachmann et al, 1994). In these cases, this marker provides very useful information for microevolutionary studies.…”

“…Its presence or absence, and the divergence of sequences shared among species, may be powerful tools, throwing light on the evolutionary relationships among closely related species. Such information has proven to be useful in a variety of organisms, for example, insects (Bachmann and Sperlich, 1993;Juan et al, 1993;Bachmann et al, 1994;Pons et al, 1997), fishes (Garrido-Ramos et al, 1995;de la Herrán et al, 2001;Lanfredi et al, 2001), birds (Madsen et al, 1992), mammals (Hamilton et al, 1992;Wijers et al, 1993;Volobouev et al, 1995;Lee et al, 1999), and plants (Galasso et al, 2001).…”

Molecular characterization of SSS139, a new satellite DNA family in sibling species of the Drosophila buzzatii cluster

“…However, despite the terminology "junk DNA" frequently associated with these sequences (Orgel and Crick, 1980), several biological roles have been suggested for some satellite DNA families, such as regulation of both heterochromatin condensation and genetic expression (reviewed by Ugarkovic, 2005). Moreover, satellite DNAs are involved in the maintenance of functional centromeres in mammals (Willard, 1990) and might also be related to the late replication of centromeres (Csink and Henikoff, 1998).The satellite DNA sequences evolve in a concerted manner (Dover, 1982) and the main molecular mechanisms involved in its evolution are slippage replication, unequal crossing-over, gene conversion and rolling circle replication, which can, in general, induce a strong intra-specific homogenization of satellite DNA sequences and interspecific divergence (Dover, 1982;Charlesworth et al, 1994).The monomers of a satellite DNA can be speciesspecific (Bachmann et al, 1994;Abadon et al, 1998) or shared among phylogenetically related species (Watabe et al, 1997;Lopez-Flores et al, 2004;Kuhn and Sene, 2005). Though there are examples of extremely conserved satellite DNA sequences among species that diverged for long evolutionary periods (de la Herrán et al, 2001;Mravinac et al 2002), most satellite DNA shared among species presents high evolutionary rates, acquiring diagnostic mutations for each species.…”

“…The monomers of a satellite DNA can be speciesspecific (Bachmann et al, 1994;Abadon et al, 1998) or shared among phylogenetically related species (Watabe et al, 1997;Lopez-Flores et al, 2004;Kuhn and Sene, 2005). Though there are examples of extremely conserved satellite DNA sequences among species that diverged for long evolutionary periods (de la Herrán et al, 2001;Mravinac et al 2002), most satellite DNA shared among species presents high evolutionary rates, acquiring diagnostic mutations for each species.…”