Mutations in Unisexual Lizard Figure 2. Intrafamily electrophoretic variability of PCR products amplified at Du281 locus of parthenogenetic lizards Darevskia unisexualis. a – family 1, b – family 2, c – family 3, d – family 4. Maternal DNAs are marked by M1–M4 respectively; offspring DNAs are shown by arrows and numbered in each family. doi:10.1371/journal.pone.0002730.g002 Table 1. Allelic variants of microsatellite clusters of Du281 locus in parthenogenetic lizard families D. unisexualis. Offspring (1, 2) allele 2 NNNCNNNGNNN(GATA)9 (GATA) (GATA)TA(GATA)NNNGNNN Maternal (M4) allele 1 NNNTNNNANNN(GATA)9 GAT(GATA)TA(GATA)NNNTNNN Offspring (1, 3, 4) allele 1 NNNTNNNANNN(GATA)9 GAT(GATA)TA(GATA)NNNTNNN Offspring (2) allele 1 Maternal (M4) allele 2 NNNTNNNANNN(GATA)9 GAT(GATA)TA(GATA)NNNTNNN NNNCNNNGNNN(GATA)9 (GATA) (GATA)TA(GATA)NNNGNNN Offspring (1, 3, 4) allele 2 NNNCNNNGNNN(GATA)9 - - - - (GATA)TA (GATA)NNNGNNN Offspring (2) allele2 NNNCNNNGNNN(GATA)9 (GATA) - - - - - - (GATA)NNNGNNN Variations in microsatellite clusters are denoted by bold letters. T-A-T and C-G-C are haplotypes specific for allelic variants of D. unisexualis [24]. In Family 2 the observed changes were the same in all offspring (1–5). In family 3 the observed changes were the same in all offspring(1, 2). In Family 4 the observed changes are the same in three offspring (1, 3 and 4). doi:10.1371/journal.pone.0002730.t001 Family 1. Maternal (M1) allele 1 Offspring (1) allele 1 Maternal (M1) allele 2 Offspring (1) allele 2 Family 2. Maternal (M2) allele 1 Offspring (1–5) allele 1 Maternal (M2) allele 2 Offspring (1–5) allele 2 Family 3. Maternal (M3) allele 1 Offspring (1, 2) allele 1 Maternal (M3) allele 2 Family 4. NNNTNNNANNN(GATA)9 (GATA) GAT(GATA)TA(GATA)NNNTNNN NNNTNNNANNN(GATA)9 - - - - GAT(GATA)TA(GATA)NNNTNNN NNNCNNNGNNN(GATA)9 (GATA) (GATA)TA(GATA)NNNGNNN NNNCNNNGNNN(GATA)9 - - - - (GATA)TA(GATA)NNNGNNN NNNTNNNANNN(GATA)9 GAT(GATA)TA(GATA)NNNTNNN NNNTNNNANNN(GATA)9 GAT(GATA)TA(GATA)NNNTNNN NNNCNNNGNNN(GATA)9 (GATA)TA(GATA)NNNGNNN NNNCNNNGNNN(GATA)9 - - - - - - (GATA)NNNGNNN NNNTNNNANNN(GATA)9 - - - - GAT(GATA)TA(GATA)NNNTNNN NNNTNNNANNN(GATA)9 (GATA)GAT(GATA)TA(GATA)NNNTNNN NNNCNNNGNNN(GATA)9 - - - - (GATA)TA(GATA)NNNGNNN Discussion Unisexual vertebrates are useful model organisms for studying genome diversity because various mutational events can be easily detected in in pedigree genotyping. The genetic variation of the majority of such species is low in comparison with their sexual progenitors, and they face severe genetic and ecological restraints [2,25]. Their genome and clonal diversity may arise as a result of mutations, multiple hybridization events, or some level of recombination occurring during continued clonal reproduction and the evolution of species [26]. In this study we characterized single highly unstable (GATA)n containing locus in parthenoge- netic lizard species D. unisexualis. Additionally, we characterized various types of mutant alleles of this locus found in the D. unisexualis offspring of the first generation. Comparison of maternal and offspring alleles of two polymorphic loci revealed de novo mutations only at the Du281 locus in D. unisexualis offspring with the mutation rate of 0.1428 events per germ line tissue. This correlates with a higher level of population polymorphism in Du281 in comparison with Du215. For instance, six and three allelic variants were detected among 65 D. unisexualis individuals for Du281 and Du215, respectively [24]. According to Malysheva [22] only three allelic variants of the Du215 locus were detected in D. armeniaca populations. The obtained mutation rate for Du281 is comparable with the earlier results of DNA fingerprinting analysis. For instance, in D. unisexualis families the observed mutational rate was 0.961022 per microsatellite band/per sibling when using a (GATA)4 hybridization probe [23]. These values are also within the range reported for individual microsatellite loci in bisexual species (from 1022 to 1024 per locus/per gamete) [21,27–29]. For instance, pedigree analysis of mutations at human microsatellite loci gave estimates of mean mutational rates of 361023–661024 [21]. Genethon’s extensive genotyping of .500 microsatellite loci in human population has suggested a lower mean genomic mutation rate, of 1024 [30,31]. A mutation rate of 5.761023 was reported for (AAAG)n tetranucleotide repeat locus in the barn swallow (Hirunda rustica) [27]. In the Australian lizard Egernia stokesii the mutational rate for (AAAG)n locus was 4.261022 [28]. A hypervariable microsatellite (TATC)n with a mutation rate of 1.761022 was found in the human X chromosome [32]. Some PLoS ONE | www.plosone.org 3 July 2008 | Volume 3 | Issue 7 | e2730