Table 1 - uploaded by Jelena V Blagojević
Content may be subject to copyright.
Source publication
Two alternative models are used to explain
maintenance of polymorphism of B chromosomes (Bs) in
populations of a great number of species. The parasitic
model suggests deleterious effects of Bs on fitness of carriers,
while the heterotic model assumes that, in the
absence of drive, equilibrium is produced by beneficial
effects of Bs at low numbers....
Context in source publication
Context 1
... analysis showed that the frequency of ani- mals with Bs was 0.23 in the population from Mt. Fruška Gora (1B = 0.75, 2-4B = 0.25), 0.38 in the population from Mt. Tara (1B = 0.56, 2-3B = 0.44), 0.35 in that from Devojački Bunar (1B = 0.44, 2B = 0.56) and 0.30 in the population from Lisine (1B = 0.86, 2B = 0.14) (Table 1). Biased estimates in statistical analyses due to disparity in sample size were avoided by appropriate pro- cedures, according to the applied tests. ...
Similar publications
The association between the African ant plant, Vachellia drepanolobium, and the ants that inhabit it has provided insight into the boundaries between mutualism and parasitism, the response of symbioses to environmental perturbations, and the ecology of species coexistence. We use a landscape genomics approach at sites sampled throughout the range o...
Citations
... On the other hand, in the Tanzawa Mountains, Kanagawa Prefecture of central Honshu (Fig. 1), one of three individuals examined shows an unusual 2n = 45 complement including only one X chromosome (XO), in spite of being female (Fukuoka and Udagawa 1979), whereas other two individuals show a standard 2n = 46 complement. Accordingly, it is expected that A. argenteus has the potential to cause chromosomal aneuploidies that seem to maintain normal fertilities and viability without any sterile influences, as in A. flavicollis (Adnađević et al. 2012). Moreover, since A. argenteus is considered to be an ancestral species of Apodemus (Serizawa et al. 2000;Matsubara et al. 2004;Suzuki et al. 2008), the cytogenetic characters of A. argenteus could provide important insight for elucidating the common mechanism of the frequent occurrence of chromosomal aneuploidy in Apodemus. ...
We studied an occurrence of chromosomal aneuploidy for ten individuals in the small Japanese field mouse, Apodemus argenteus, from the western mountainous area of Kanagawa Prefecture, Honshu, Japan. Eight of the individuals examined showed the standard 2n = 46 and FNa = 48 constitutions as the most frequent karyotype. However, of those eight individuals, seven carried an inter-cellular mosaicism with a few metaphases carrying a small-sized supernumerary element. In addition, one individual showed an aneuploid complement that included a small-sized bi-armed B chromosome (2n = 47). The B chromosome consisted of the C-heterochromatin and was characterized by delayed fluorescence by the quinacrine mustard staining, suggesting that its feature is identical to the B chromosomes previously confirmed in other localities. Moreover, an XO female showing a standard autosomal complement with only one X chromosome (2n = 45, XO) was also recognized. According to the present observations, these chromosomal aneuploidies are retained in wild populations of A. argenteus as constantly occurring phenomena.
... Possible adaptive effects of Bs were also postulated by Blagojević et al. [234] upon comparison of head morphology in three populations of this species that have Bs at different frequencies. Adnađević et al. [235], by using amplified fragment length polymorphism (AFLP) markers, made a comparison of populations of A. flavicollis settled in ecologically distinct habitats differing in frequency of Bs, and found that the greatest genetic diversity is in the population settled in optimal conditions for this species featured by the lowest frequency of animals with Bs. The majority of loci that are subject of directional selection, feature either population with lower or with a higher frequency of Bs. ...
The study of B chromosomes (Bs) started more than a century ago, while their presence in mammals dates since 1965. As the past two decades have seen huge progress in application of molecular techniques, we decided to throw a glance on new data on Bs in mammals and to review them. We listed 85 mammals with Bs that make 1.94% of karyotypically studied species. Contrary to general view, a typical B chromosome in mammals appears both as sub- or metacentric that is the same size as small chromosomes of standard complement. Both karyotypically stable and unstable species possess Bs. The presence of Bs in certain species influences the cell division, the degree of recombination, the development, a number of quantitative characteristics, the host-parasite interactions and their behaviour. There is at least some data on molecular structure of Bs recorded in nearly a quarter of species. Nevertheless, a more detailed molecular composition of Bs presently known for six mammalian species, confirms the presence of protein coding genes, and the transcriptional activity for some of them. Therefore, the idea that Bs are inert is outdated, but the role of Bs is yet to be determined. The maintenance of Bs is obviously not the same for all species, so the current models must be adapted while bearing in mind that Bs are not inactive as it was once thought.
... Current study revealed weak population structure. Although ΔK showed the highest value at K=4 (9.57), it is comparatively smaller than those reported for populations confirmed to have defined structures (Haanes et al. 2011, Adnađević et al. 2012, Marić et al. 2012, Taugbol et al. 2013 where the highest ΔK values are 300, 179, 839 and 130, respectively. Since the method described by Evanno et al. (2005) could not evaluate ΔK when K=1, and given that the log probability values (Ln P(X/K)) are highest for K=1, there seems to be no real population structure among the sampling sites. ...
Sterlet populations have experienced a decline during the 20th century throughout its range, mainly due to poorly regulated fisheries, pollution, habitat fragmentation and habitat loss. They still represent a species of significant economic importance in the Middle and Lower Danube, so the present study was designed to investigate genetic diversity of wild sterlet populations from the Middle and Lower Danube and Lower Tisza rivers, as a prerequisite for their effective conservation and management. By applying ten microsatellite loci, we determined that pair-wise FST values were particularly low (0.018-0.038), indicating the presence of a gene flow and a low level of sub-structuring among the assessed locations. This trend can be also observed in allele sharing distance based NJ tree. Genetic variance could be attributed almost entirely to individuals, with no detectable strong population structure. Our analysis revealed considerable variation in the detection of a genetic bottleneck. Point estimate methods revealed different effective population sizes, with the lowest value being 8.1. Our study indicated the need for a careful planning of sterlet stocking programmes.
... In rye a negative correlation between the frequency of plants with Bs and the mean heterozygosity at isozymal loci was detected (Benito et al. 1994). In the yellow-necked mouse, Apodemus flavicollis, analysis of AFLP loci demonstrated that individuals with and without Bs showed similar levels of genetic variability (Adnadevic et al. 2012). ...
Dichroplus elongatus is an extensively distributed South American grasshopper considered a pest of major crops. Argentinean populations show a widespread B-chromosome polymorphism which could be maintained as the result trade-offs among opposite selective effects and interactions with their mitotic instability. The main objective of this study was to evaluate the relationships between B chromosomes and mtDNA sequences coupled with minisatellites loci, and verify the genotype/karyotype covariation in 12 populations located at both sides of Paraná River (Eastern and Western Regions). B carrier individuals showed significantly higher genetic diversity (HE and X) respect to standard individuals. AMOVAs based on nuclear loci and mtDNA sequence datasets showed statistically significant levels of differentiation among karyotypes in the Eastern Region. Cluster analysis through Bayesian procedure considering nuclear loci splits B carriers and standard individuals into different genetic clusters in some Eastern populations. The Bayesian phylogenetic analysis showed two divergent mtDNA clades. Haplogroup 1 is composed exclusively of standard individuals, however all B chromosome carriers are included in haplogroup 2. There is an association between some haplotypes and B chromosomes and a strong effect of phylogenetic signal on B chromosome population structure. Genetic differentiation between karyotypes at Eastern Region revealed by AMOVA, Bayesian approaches and clustering analysis based on uniparental and biparental inherited markers may be due to the inherent nature of the B chromosome, to karyotype biased dispersal or to difference tolerance of B chromosomes on different genetic background. The combination of molecular and chromosome analysis performed in this study indicated that B chromosomes in D. elongatus is an important factor in explaining the genetic population structure at minisatellite and mitochondrial DNA levels.
... Reported B chromosome prevalence ranged from 11% to 63% in 13 out of 14 populations studied in former Yugoslavia [21,22]. A possible reason for their long-term presence in populations could be their contribution to: genetic variability, adaptive effects and population dynamics [22][23][24][25]. ...
Since the density of simple sequence repeats (SSRs) may vary between different chromosomes of the same species in eukaryotic genomes, we screened SSRs of the whole genome of the yellow necked mouse, Apodemus flavicollis, in order to reveal SSR profiles specific for animals carrying B chromosomes. We found that the 2200 bp band was amplified by primer (CAG) 4 AC to a highly increased level in samples with B chromosomes. This quantitative difference (B-marker) between animals with (+B) and without (0B) B chromosomes was used to screen 20 populations (387 animals). The presence/absence of Bs was confirmed in 96.5% of 342 non mosaic individuals, which recommends this method for non-invasive B-presence detection. A group of 45 animals with mosaic and micro B (μB) karyo-types was considered separately and showed 55.6% of overall congruence between karyotyping and molecular screening results. Relative quantification by qPCR of two different targeted sequences from B-marker indicated that these B-specific fragments are multiplied on B chromosomes. It also confirms our assumption that different types of Bs with variable molecular composition may exist in the same individual and between individuals of this species. Our results substantiate the origin of Bs from the standard chromosomal complement. The B-marker showed 98% sequence identity with the serine/threonine protein kinase VRK1 gene, similarly to findings reported for Bs from phylogenetically highly distant mammalian species. Evolutionarily conserved protein-coding genes found in Bs, including this one in A. flavicollis, could suggest a common evolutionary pathway.
... Furthermore, population genetics and dynamics also have an influence on the structure of the parasite fauna of the yellownecked field mouse (Ferrari, 2005) and possibly explain the differences and similarities found here. In a recent study of yellow-necked field mouse populations in Serbia it was shown that their genetic structure did not reflect geographical distances and predicted barriers (large rivers); rather, it reflected differences in the habitats (Adnadević et al., 2012). In particular, the authors found no statistically significant differences in genetic diversity between two localities separated by the Danube. ...
Up to six nematode species were identified from 86 specimens of the yellow-necked field mouse Apodemus flavicollis from three mountainous localities known as Avala, Cer and Liškovac in Serbia. The highest prevalence of infection of 97% was recorded from Mt. Avala. Only one nematode species, Syphacia frederici, occurred in all three localities. There was complete overlap in nematode species from Mts. Avala and Liškovac, whereas the taxonomic distinctness of Mt. Cer was seen in the presence of the insect-transmitted species Rictularia proni. Locality was a statistically significant factor in all the best-fitted generalized linear models of variation in abundances. The highest level of both species richness and parasite alpha diversity (Shannon's H= 1.47) was found in the easternmost Mt. Liškovac, whereas the diversity indices were lowest for the westernmost Mt. Cer (Shannon's H= 0.48). In view of this geographical difference, the beta diversity indices were calculated along a west to east longitudinal gradient.
... Both dominantly and co-dominantly inherited markers have been used in population genetics studies of many species (Bugarski-Stanojević et al., 2011; Adnađević et al., 2012; Jelić et al., 2012a,b; Skorić et al. 2012; Živković et al., 2012; Banjanac et al., 2014). Since the 90-ies, microsatellite markers have become increasingly popular in plant population genetics due to their high variability. ...
Empirical population genetic studies have been dominated by a neutralist view, according to which gene flow and drift are the main forces driving population genetic structure in nature. The neutralist view in essence describes a process of isolation by dispersal limitation (IBDL) that generally leads to a pattern of isolation by distance (IBD). Recently, however, conceptual frameworks have been put forward that view local genetic adaptation as an important driver of population genetic structure. Isolation by adaptation (IBA) and monopolization (M) posit that gene flow among natural populations is reduced as a consequence of local genetic adaptation. IBA stresses that effective gene flow is reduced among habitats that show dissimilar ecological characteristics, leading to a pattern of isolation by environment. In monopolization, local genetic adaptation of initial colonizing genotypes results in a reduction of gene flow that fosters the persistence of founder effects. Here, we relate these different processes driving landscape genetic structure to patterns of IBD and isolation by environment (IBE). We propose a method to detect whether IBDL, IBA and M shape genetic differentiation in natural landscapes by studying patterns of variation at neutral and non-neutral markers as well as at ecologically relevant traits. Finally, we reinterpret a representative number of papers from the recent literature by associating patterns to processes and identify patterns associated with local genetic adaptation to be as common as IBDL in structuring regional genetic variation of populations in the wild. Our results point to the importance of quantifying environmental gradients and incorporating ecology in the analysis of population genetics. This article is protected by copyright. All rights reserved.
