Intra- and interspecific polymorphism of (AAT) n in microsatellite locus Du47D in parthenogenetic species of the genus Darevskia

The molecular structure of the allelic variants of (AAT) _n of the Du47D microsatellite locus was determined in parthenogenetic lizards Darevskia dahli, D. armeniaca, and D. rostombekovi. Comparative analysis of these alleles showed that they were characterized by perfect structure of microsatellite cluster, and were different in the number of (AAT) monomeric units, as well as in the combinations of species-specific substitutions and deletions in the microsatellite flanking regions. Molecular structure of microsatellite cluster, species-specific single nucleotide polymorphism (SNP), and different representation of alleles Du47 in the samples of parthenogenetic species examined point to the origin of the alleles from different bisexual species, which is consistent with the hybrid nature of unisexual species of the genus Darevskia. In addition, these data reflect different combination patterns of interspecific hybridization events with the participation of the same bisexual species upon the formation of hybrid genomes of parthenogenetic species. Possible application of the allelic variants of microsatellite loci of parthenogenetic lizards as the genetic markers for the analysis of the genomes of parthenogenetic species in the light of evolution, ecology, and parthenogenetic type of reproduction in vertebrates is discussed.     

Nucleotide sequences of the microsatellite locus Du215 (arm) allelic variants in the parthenospecies Darevskia armeniaca (Lacertidae)

Using monolocus PCR analysis with the pairs of primers designed for the Du215 locus of Darevskia unisexualis, allelic polymorphism at the orthologous locus in the populations of the related parthenospecies D. armeniaca was investigated. It was demonstrated that Du215 (arm) locus was polymorphic and in the populations of parthenospecies D. armeniaca (n = 127) represented by at least three allelic variants, differing from each other by the size and composition of microsatellite cluster, and by single nucleotide substitutions in flanking DNA. Unlike the Du215 locus, Du215 (arm) was shown contain not only GATA, but also (GACA) repeats, which were absent in D. unisexualis. Thus, in this study, the data on the molecular nature of allelic polymorphism at one of the microsatellite loci of the parthenospecies D. armeniaca were reported.     

Molecular characterization of allelic variants of (GATA)n microsatellite loci in parthenogenetic lizards Darevskia unisexualis (Lacertidae)

Populations of parthenogenetic lizards of the genus Darevskia consist of genetically identical animals, and represent a unique model for studying the molecular mechanisms underlying the variability and evolution of hypervariable DNA repeats. As unisexual lineages, parthenogenetic lizards are characterized by some level of genetic diversity at microsatellite loci. We cloned and sequenced a number of (GATA)n microsatellite loci of Darevskia unisexualis. PCR products from these loci were also sequenced and the degree of intraspecific polymorphism was assessed. Among the five (GATA)n loci analysed, two (Du215 and Du281) were polymorphic. Cross-species analysis of Du215 and Du281 indicate that the priming sites at the D. unisexualis loci are conserved in the bisexual parental species, D. raddei and D. valentini. Sequencing the PCR products amplified from Du215 and Du281 and from monomorphic Du323 showed that allelic differences at the polymorphic loci are caused by microsatellite mutations and by point mutations in the flanking regions. The haplotypes identified among the allelic variants of Du281 and among its orthologues in the parental species provide new evidence of the cross-species origin of D. unisexualis. To our knowledge, these data are the first to characterize the nucleotide sequences of allelic variants at microsatellite loci within parthenogenetic vertebrate animals.     

Molecular and genetic characterization of the allelic variants of Du215, Du281, Du323, and Du47G microsatellite loci in parthenogenetic lizard <Emphasis Type="Italic">Darevskia armeniaca</Emphasis> (Lacertidae)

A key issue in the study of unisexual (parthenogenetic) vertebrate species is the determination of their genetic and clonal diversity. In pursuing this aim, various markers of nuclear and mitochondrial genomes can be used. The most effective genetic markers include microsatellite DNA, characterized by high variability. The development and characterization of such markers is a necessary step in the genetic studies of parthenogenetic species. In the present study, using locus-specific PCR, for the first time, an analysis of allelic polymorphism of four microsatellite loci is performed in the populations of parthenogenetic species Darevskia armeniaca. In the studied populations, allelic variants of each locus are identified, and the nucleotide sequences of each allele are determined. It is demonstrated that allele differences are associated with the variation in the structure of microsatellite clusters and single nucleotide substitutions at fixed distances in flanking DNA regions. Structural allele variations form haplotype markers that are specific to each allele and are inherited from their parental bisexual species. It is established which of the parental alleles of each locus were inherited by the parthenogenetic species. The characteristics of the distribution and frequency of the alleles of microsatellite loci in the populations of D. armeniaca determining specific features of each population are obtained. The observed heterozygosity of the populations at the studied loci and the mutation rates in genome regions, as well as Nei’s genetic distances between the studied populations, are determined, and the phylogenetic relationships between them are established.     

Electronic structures of collagen model polymers: (Gly-Pro)n, (Gly-Hyp)n, (Ala-Pro)n, (Ala-Hyp)n, (Gly-Pro-Gly)n, (Gly-Hyp-Gly)n, (Gly-Pro-Pro)n, and (Gly-Pro-Hyp)n

In order to investigate the relationship existing between the electronic structures of collagen and its biochemical functions in vivo, the semiempirical CNDO/2 SCF MO calculations were carried out on several model polymers of collagen, (Gly-Pro)_n, (Gly-Hyp)_n, (Ala-Pro)_n, (Ala-Hyp)_n, (Gly-Pro-Gly)_n, (Gly-Hyp-Gly)_n, (Gly-Pro-Pro)_n and (Gly-Pro-Hyp)_n. Geometries of the skeleton of these polymers were assumed to be the same as those of poly(l-proline) I (cis) and II (trans) and the calculations were performed only on infinite polymers in a single chain. The results show that the cis form is always more stable than the trans form for all the polymers treated. This energy difference between the cis and trans forms depends, for example, on the kind of amino acid residue, Gly or Ala, but this could not be seen in the Pro or Hyp residue. The flexibility or mobility of the collagen structure was explained using the energy difference between the cis and trans forms of the polymers, i.e. the cis-trans conversion of the collagen was discussed in connection with the energy difference. The reason why the collagen has the constitution of (Gly-Pro-Hyp)_n is briefly discussed.     

Molecular nature of allelic polymorphism of highly variable microsatellite locus Du161(arm) in unisexual lizard Darevskia armeniaca (Lacertidae)

In the genome of unisexual (parthenogenetic) lizard Darevskia armeniaca, highly variable locus Du 161 (arm) was discovered. Analysis of allelic polymorphism was carried out using locus-specific PCR of the lizard DNA specimens from 13 isolated Armenian populations (N = 138). In the sample examined, a total of 12 Du 161(arm) alleles were identified, and their differences at the level of primary DNA structure were determined. Sequence analysis of the Du 161 (arm) alleles showed that their microsatellite clusters contained repeats of one type (GATA repeats). Allelic Du 161 (arm) variants differed in the number of GATA monomers in microsatellite, point mutations of transition and transversion types, located at fixed distances from microsatellite cluster, and by single nucleotide insertions, as well as by longer insertions located within and outside of the microsatellite cluster. Moreover, point mutations formed different combinations (haplotypes), typical of certain alleles. These combinations can be used for the analysis of the origin and inheritance of these alleles in D. armeniaca, as well as for investigation of their interspecific variation in the representatives of the genus Darevskia.     

Molecular structure of allelic variants of microsatellite loci <Emphasis Type="Italic">Du281</Emphasis> and <Emphasis Type="Italic">Du47</Emphasis> in unisexual and bisexual lizard species of the genus <Emphasis Type="Italic">Darevskia</Emphasis>

Experimental data on the molecular structure and variability of microsatellite loci in unisexual and bisexual lizard species of the genus Darevskia were analyzed. The allelic variants of Du281 and Du47 were found to differ in the number of monomers, the structure of microsatellite clusters, and point mutations in these clusters and flanking DNA. Interspecific comparison of alleles of these loci revealed both variable regions in the microsatellite clusters and allele-specific evolutionarily conserved nucleotide groups. In general, the results of comparative structural analysis of allelic variants testify to a high genetic similarity of the unisexual and bisexual lizard species studied and reveals the characteristic features of their interspecies variability.     

Finding of Bov-B LINE retroelement in parthenogenetic and bisexual lizard species of the genus Darevskia (Lacertidae)

The Bov-B LINE retrotransposon was first discovered in Ruminantia and was long considered to be specific for this order. Later, this mobile element was described in snakes and some lizard species. Analysis of phylogenetic relationships of Bov-B LINE elements from different ruminants, snakes, and lizard species led to the suggestion on horizontal transfer of this retrotransposon from Squamata to Ruminantia. In the Squamata group, Bov-B LINE element was found in all snakes and some lizard species examined. The element was not detected in the genomes of some species of the genera Lacerta and Podarcis. In the present study, using PCR amplification and sequencing of PCR products, Bov-B LINE element was identified in the genomes of parthenogenetic and bisexual species of the genus Darevskia (Lacertidae), as well as in such species as Lacerta agilis and Zootoca vivipara, where this retrotransposon had not been not detected before.     

Genetic and phenotypic variation for flight ability in the cactophilicDrosophila species,D. aldrichi andD. buzzatii

The flight ability ofDrosophila aldrichi (Patterson & Crow) andD. buzzatii (Patterson & Wheeler) using tethered flights, was measured with respect to age-related changes, genetic variation and adult body size variation induced by rearing at different larval densities.Drosophila buzzatii flew for much longer thanD. aldrichi, especially females, but age-related changes in flight duration were significant only forD. aldrichi. Effects of body size on flight ability were significant inD. buzzatii, but not inD. aldrichi. InD. buzzatii, there was a significant genotype-environment interaction (larval density × line) for flight duration, with short and average flight duration isofemale lines showing longer flights, but a long flight duration line shorter flights as body size decreased (i.e., as larval density increased). Heritability estimates for flight duration were similar in the two species, but flight duration showed no significant genetic correlations with developmental time, body size or wing dimensions (except for one wing dimension inD. buzzatii). Although not significantly different between the species, heritabilities for life-history traits (adult size and developmental time) showed contrasting patterns — with higher heritability for body size (body weight and thorax length) inD. buzzatii, and higher for developmental time inD. aldrichi. In agreement with limited previous field evidence,D. buzzatii is better adapted for colonization than isD. aldrichi.     

Home ranges of parthenogenetic and bisexual species in a community of Darevskia lizards (Reptilia: Lacertidae)

We analysed the home ranges of a community of Darevskia rock lizards composed of a bisexual species (D. valentini), two parthenogens (D. armeniaca and D. unisexualis), and two backcross forms between bisexual and unisexual forms. We estimated home range areas of ink-marked, GPS-located lizards using Minimum Convex Polygon (MCP) and 95% of the locations for those individuals with five or more sightings. The bisexual D. valentini was the species with the largest home ranges, distances travelled, and the most intersections. No differences between unisexual species and backcrosses were recorded for any comparison. In males, home range size and perimeter were related to morphological characteristics. Contrary to what has been described in allopatry, unisexual species showed smaller home ranges and fewer overlaps than sympatric bisexual species. We tentatively suggest that the presence of potential bisexual partners might increase sexual competition among parthenogenetic females while differences in habitat use should also be considered.     

Conservation of (GA)n microsatellite loci between Quercus species

Microsatellite (simple sequence repeat, SSR) amplification was performed in eight different members of the Fagaceae family by using sets of primers developed from sessile oak, Quercus petraea . In total, 136 cases of heterologous amplification were carried out, and 66% resulted in interpretable amplification products. From these, 12 PCR amplification products were sequenced and all 12 contained a sequence homologous to the original locus from Q. petraea . Although SSR primers worked even across different genera, with increasing evolutionary distance there was a clear tendency for decreasing ability to successfully amplify loci and a decreasing proportion of polymorphism amongst those markers which could be amplified. Two of the loci, ssrQpZAG46 and ssrQpZAG110, were polymorphic in all Quercus species tested. Only at one locus, ssrQpZAG58, a specific PCR product could be amplified in all species analysed. For four loci found in two species, we observed significant interspecies differences in the size range of the amplified alleles. Sequence analysis of two alleles showed that the size differences are not only due to variations in the number of (GA) repeats but also to an insertion of approximately 80 nucleotides in the flanking region. Our findings prove the usefulness of SSR markers within and amongst closely related genera of plants.     

中国毛茛科翠雀属的分类学研究(四):五花翠雀花的名实订正

通过标本室和野外观察,发现根据云南中甸标本描述的毛茛科五花翠雀花(Delphinium quinqueflorum W.T.Wang)与当地颇为常见的澜沧翠雀花(D.thibeticum Finet&Gagnep.)没有本质区别,仅为其稍矮小的植株,故将前者处理为后者的异名。     

Diospyros foliosa: the correct name for D. elliptica, and new combinations in Fijian and Samoan Diospyros (Ebenaceae)

The correct name in Diospyros L. (Ebenaceae) for a species from Tonga first described as Maba elliptica J. R. Forst. & G. Forst. and incorrectly known as D. elliptica (J. R. Forst. & G. Forst.) P. S. Green is D. foliosa (A. Gray) Bakh. In addition to the nominate variety, six additional varieties are recognised from Fiji and Samoa. As these varieties lack names under D. foliosa, the following new combinations are proposed: D. foliosa var. elliptica (J. R. Forst. & G. Forst.) Dorr, D. foliosa var. fijiensis (Bakh.) Dorr, D. foliosa var. fructuosa (A. C. Sm.) Dorr, D. foliosa var. iridea (Fosberg) Dorr, D. foliosa var. opaca (A. C. Sm.) Dorr, and D. foliosa var. savaiiensis (Christoph.) Dorr.     

Differential Role of Poly(ADP-ribose) polymerase in D. discoideum growth and development

Background  

Poly(ADP-ribose) polymerase is evolutionarily conserved as a responder to various forms of stress. Though PARP's role in cell death is well addressed, its role in development and multicellularity is still an enigma. We have previously reported the role of PARP in oxidative stress induced delayed development of D. discoideum.     

中国毛茛科翠雀属的分类学研究(五):秋翠雀花二新异名

通过标本室和野外观察,发现根据四川西南部越西标本描述的毛茛科凉山翠雀花(Delphinium liangshanense W. T. Wang)和根据四川西南部木里标本描述的光轴翠雀花(D. leiostachyum W. T. Wang)只是此前记载分布于四川木里、盐源和云南西北部宁蒗一带的秋翠雀花(D. autumnale Hand.-Mazz.)植株较高的类型,故将二者均处理为秋翠雀花的异名.     

中国毛茛科翠雀属的分类学研究(十四):光序翠雀花二新异名

广布于中国-喜马拉雅地区的毛茛科光序翠雀花（Delphinium kamaonense Huth）在我国甘肃、青海、四川和西藏具有相当连续的分布区,在分布区内颇为常见,几为杂草。通过标本室和野外观察,发现根据西藏波密、察隅标本描述的展毛光序翠雀花[D. kamaonense var. glabrescens（W. T. Wang）W. T. Wang]和根据西藏类乌齐标本描述的倒心形翠雀花（D. obcordatilimbum W. T. Wang）与光序翠雀花没有本质区别,故将二者均处理为光序翠雀花的异名。     

Cytogenetics of the parthenogenetic grasshopper Warramaba (formerly Moraba) virgo and its bisexual relatives

The distribution of late-replicating segments along the chromosomes of five clones of W. virgo is described. Some, but not all of these segments correspond to C-bands. In general, the autoradiographic profiles (histograms of linear grain density along the length of chromosomes labeled with tritiated thymidine in late S-phase) show strong resemblances throughout the five clones. However, some significant differences exist, and these are particularly marked in the case of the Boulder clone, which is anomalous in many other respects. — A similar study has also been carried out on the two bisexual species of Warramaba (P169 and P196) that gave rise, by hybridization more than half a million years ago, to the parthenogenetic W. virgo. In the case of P169, the autoradiographic profiles of the three large chromosomes (X+A, B+5, CD) which it has contributed to the W. virgo karyotype are extremely similar to those of the corresponding chromosomes in the virgo clones we have studied. In the case of P196 there is likewise, in most instances, a close resemblance of the autoradiographic profiles of the AB, X₁ and CD chromosomes to those of the same chromosomes in the virgo clones, but that of the X₁ shows no particular resemblance to the anomalous profile of the X₁ in the Boulder clone, in which the X₁ has undergone a structural reorganisation. The autoradiographic profile of the P196 CD chromosome does, however, show a much closer resemblance to that of the corresponding chromosome in the Boulder clone than to those of the CD₁₉₆ in the other four virgo clones studied. These investigations confirm the considerable evolutionary stability of DNA replication patterns.     

Cytogenetics of the parthenogenetic grasshopper Warramaba (formerly Moraba) virgo and its bisexual relatives

Triploid hybrids have been obtained by crossing individuals of the diploid Warramaba virgo with males of two undescribed related species of Warramaba, P169 (neo-XY) and P196 (X₁X₂Y). In both cases, offspring which receive a Y-chromosome from the father are males, while those that receive a neo-X from P169 or an X₁ and an X₂ from P196 are females. The triploids can be distinguished from diploids, even in the earliest nymphal instars, by the larger size of their eye facets. Their gonads are undeveloped and abnormal so that they are mostly sterile (the males absolutely so). Nevertheless, in the case of female hybrids (both the ones between virgo and P169 and those between virgo and P196) a few oocytes do develop and it was possible to obtain a further generation of hybrids by parthenogenesis. These, which are all female, and have karyotypes identical to those of their mothers, are derived from eggs which have undergone the virgo type of meiosis, with a premeiotic doubling of the chromosome number, followed by synapsis restricted to sister chromosomes. — Some diploid hybrids have also been obtained between the bisexual species P169 () and P196 (). In this case the male offspring died in the embryonic stage or immediately after hatching. Female hybrids, on the other hand, were viable but had under-developed ovaries, so that they only laid very few eggs. Some of the latter developed into embryos with a karyotype identical to that of the mother, but the meiosis of these eggs has not yet been studied, so that it is not known whether it is of the virgo type. These hybridization experiments support the hypothesis that virgo originated as a hybrid between P196 and P169. — A single male hybrid between Warramaba picta () and P169 () was obtained; it had active spermatogenesis, but many meiotic abnormalities.     

Mapping of the Gracile Axonal Dystrophy (gad) Gene to a Region between D5Mit197 and D5Mit113 on Proximal Mouse Chromosome 5

The gracile axonal dystrophy (gad) mouse, which shows hereditary sensory ataxia and motor paresis, has been morphologically characterized by the dying back type of axonal degeneration in the nerve terminals of dorsal root ganglion cells and motor neurons. In the present study, using an intraspecific backcross between gad and C57BL/6J mice, the gracile axonal dystrophy (gad) gene was mapped to a region between D5Mit197 and D5Mit113. Estimated distances between gad and D5Mit197 and between gad and D5Mit113 are 0.4 ± 0.3 and 5.0 ± 1.0 cM, respectively. The gene order was defined: centromere- D5Mit81-D5Mit233-D5Mit184/D5Mit254-D5Mit256-D5Mit197-gad-D5Mit113-D5Mit7 . The mouse map location of the gad locus appears to be in a region homologous to human 4p15-p16. Our present data suggest that the nearest flanking marker D5Mit197 provides a useful anchor for the isolation of the gad gene in a yeast artificial chromosome contig.