To re-evaluate the taxonomic status of Cheilosia canicularis (Panzer, 1801), C. himantopus (Panzer, 1798) and C. orthotricha Vujić & Claussen, 1994, variation in the mitochondrial DNA (mtDNA) sequence of the cytochrome c oxidase subunit I (COI) gene and 18 nuclear allozyme genes were surveyed in allopatric and sympatric populations from Serbia and Montenegro. Genetic relationships among five populations of these species from the Fruška Gora (Serbia), Kopaonik (Serbia) and Durmitor (Montenegro) mountains were analyzed. Seven allozyme loci (Aat, Aco, Fum, Idh-1, Idh-2, Mdh-2 and Sdh) were diagnostic for delineating C. orthotricha from the other two species, while only a low, but consistent, genetic differentiation was observed between C. canicularis and C. himantopus. Differentiating all three species was possible based solely on the species-specific alleles at the Est-? locus. Sequence comparisons of 738 bp of the COI gene from eleven specimens was consistent with the variability in nuclear allozymes. Sequence data revealed variation in 5% of the nucleotide sites among C. orthotricha and the C. canicularis/C. himantopus pair, while less variation (0.68%) was observed within the pair C. canicularis/C. himantopus. However, the presence of one diagnostic allozyme locus and five consistently variable nucleotide sites in sympatric populations of C. canicularis and C. himantopus (Durmitor, Montenegro) suggest that these two species have separate gene pools.
Variation of 15 nuclear allozyme genes and a 708 bp fragment of DNA sequence of the mitochondrial cytochrome c oxidase subunit I (COI) gene were surveyed in a population of a hoverfly species, Merodon desuturinus Vujić, Šimić & Radenković, 1995 (Diptera, Syrphidae), endemic to the Balkan Peninsula. Based on phylogeography and taxonomy, Merodon desuturinus is of special interest from a biogeographical and conservation perspective. Characterization and determination of genetic relationships between M. desuturinus and taxa of the M. aureus, M. avidus, and M. ruficornis groups on the Balkan Peninsula were estimated based on molecular markers (allozymes and COI sequences). We observed that the mean number of alleles per allozyme locus was 1.1, frequency of polymorphic loci 0.067, and heterozygotes were absent. Our results showed an extremely low genetic variability in the M. desuturinus population sampled. We suggest that this taxon calls for a conservation management plan, as it is likely a vulnerable and threatened taxon, an endemic, spatially divided species and represents a unique genetic unit on the Balkan Peninsula.
Genetic variability within and among fragmented populations of Artemisia pancicii was investigated in order to obtain a general understanding of the genetic structure related to the successful protection of this highly endangered species. Genetic variation within and among 15 populations of A. pancicii in Central Europe was analysed using amplified fragment length polymorphism (AFLP) and sequencing of two chloroplast DNA regions. The resulting polymorphism of AFLP loci was interpreted using basic population genetic indices and statistical visualisation. The total genetic variability within the populations was high (Ht = 0.248) and a highly differentiated population pattern (Fst = 0.241) was revealed. An analysis of molecular variance (AMOVA) revealed high variation among the populations (82%). There was no significant correlation between the genetic and geographic distance matrices. This indicates that population relatedness is not reflected in their geography. This was also confirmed by cpDNA sequencing. Highly restricted gene flow among the populations and genetic drift has resulted in reduced genetic variability in the smaller and highly differentiated A. pancicii populations, and very probably implies the presence of self-incompatibility and prevalence of clonal reproduction. The conservation of genetic variability in A. pancicii requires the persistence of large and also of small populations (because of population differentiation). The most important factor for the preservation of this species in the localities studied is the application of appropriate conservation management (such as mowing, grazing or fire management).
The morphology, physiology, behaviour and ecology of spiralling whitefly, Aleurodicus dispersus Russell (Hemiptera: Aleyrodidae) on different host plants differ greatly. The genetic differences between the A. dispersus populations on 17 host plants were evaluated in the current study. Microsatellite markers were used to identify the presence of host-related genetic variation among A. dispersus populations. Our research clearly shows that there is a significant amount of genetic divergence among the A. dispersus populations on 17 host plants in India. The spiralling whitefly on acalypha and calotropis were genetically more distinct than whiteflies on other host plants. Various population genetic parameters, like heterozygosity, Nei's genetic distance, fixation indices (FST), source of genetic variation in AMOVA, etc. indicate that populations of spiralling whiteflies differ greatly genetically, probably because the spiralling whitefly populations on the Indian sub-continent came from multiple sources. The results of this study have implications for the quarantine protection strategy against this invasive pest.
Sample of Gobio gobio from 30 localities in the Czech Republic and Slovak Republic were studied. Starch gel electrophoresis was used for evaluation of variability of allozyme patterns in 16 active protein systems comprising 26 loci. Products of 17 loci were considered to study the genetic structure of its populations. From this, genetic variability was found in ten loci, occurrence of rare alleles was detected in next four loci. Percentage of polymorphic loci ranged between 6 and 41%; mean occurrence of alleles was between 1.1 and 2.0 per locus; and mean heterozygosity was observed at 0.013 to 0.248. The genetic distances among populations were 0.002 to 0.175 (N e i 1972) and 0.063 to 0.385 (C a v a l l i - S f o r z a & E d w a r d s 1967). Differences in occurrence and frequencies of alleles in some loci among the sea basins were evident. Higher genetic variability identified in populations from the Danube river system (Black See basin) is probably connected with the fact that this basin served as a refuge for ichthyofauna during glaciations.
The quantitative changes of chloroplast ultrastructure and dimensions in mesophyll (MC) and bundle sheath (BSC) cells, associated with the onset of leaf senescence, were followed along the developmental leaf blade gradient of the third leaf of maize (Zea mays L.). To ascertain whether the rapidity of structural changes associated with the transition of chloroplasts from mature to senescent state is a heritable trait, the parental and the first filial generations of plants were used. The heterogeneity of leaf blade, associated with the development of maize leaf (with the oldest regions at the apex and the youngest ones at the base) was clearly discernible in the ultrastructure and dimensions of chloroplasts; however, there were differences in the actual pattern of chloroplast development between both genotypes as well as between both cell types examined. While the course of MC chloroplasts' development at the onset of leaf senescence in maize hybrid followed that of its parent rather well, this did not apply for the BSC chloroplasts. In this case, each genotype was characterized by its own distinguishable developmental pattern, particularly as regards the accumulation of starch inclusions and the associated changes of the size and shape of BSC chloroplasts. and A. Vičánková, D. Holá, J. Kutík.
Aleurodicus dispersus Russell (Hemiptera: Aleyrodidae), a highly polyphagous species, has since the 90's been an important pest of ornamentals and tropical crops in the Canary Islands. In this study the RAPD-PCR technique was used to study the genetic structure of this whitefly in this archipelago. A total of 68 different bands were scored in seven populations using six primers for amplification. No differences in RAPD patterns were found among populations from different islands of the Canaries. These findings indicate a very high genetic similarity among populations and low level of genetic variability and support a single colonization event by few A. dispersus whiteflies and recent dispersion throughout the archipelago.
Heat stress is a major production constraint of sunflower worldwide. Therefore, various populations (parental, F1, F2, F3, and plant progenies) of sunflower were screened for leaf gas-exchange traits with the objectives to formulate selection criteria of heat resistance and development of heat-resistant lines. Initial screening and F2 seeds exposed to heat stress (45°C) resulted in the development of an adapted F2 population that showed leaf gas-exchange and morphological traits better than the unadapted population. Correlation coefficients of traits were partitioned into direct and indirect effects via a path analysis technique to determine the cause of their relationship with a basic parameter such as a reproductive head mass (HM). Path analysis showed a positive direct effect of leaf temperature (Tleaf) (0.32) on HM and also an indirect effect (0.77) of the transpiration rate (E) on HM. Moreover, Tleaf showed high heritability estimates. Tleaf was used to select superior plants within the F2 population. This selection brought about an improvement in the net photosynthetic rate (PN) and E as it was indicated from progeny performance and realized heritability. Progenies selected on the basis of Tleaf also showed an increase in achene yield and heat resistance over unselected F3 progenies and a commercial hybrid. and T. Kalyar ... [et al.].