[en] This study was undertaken to determine the genetic structure and the diversity between 2 local cattle breeds from Bulgaria, the Rhodope Shorthorn and Grey cattle. A panel of 11 microsatellites was used for the evaluation. For these loci, allele frequencies, heterozygosity, HWE, genetic disequilibrium were determined. Both populations displayed a relatively high level of genetic variation as estimated by allelic diversity and heterozygosity. Heterozygosities ranged from 0.5424 /SPS 115/ to 0.8983 /TGLA 227/ for the Rhodope population and 0.6333 /TGLA 53/ to 0.9333 /TGLA227/ for Grey cattle, with similar average values for the two groups - 0.7858 and 0.7757. This study contributes to the knowledge of the genetic diversity, genetic structure and to the molecular characterization of small populations on the brink of extinction. Since the actual implementation of a sustainable program for the conservation of animal genetic resources requires a wide variety of technologies and approaches it is now possible to characterize them at DNA level. Both Grey and Rhodope Shorthorn cattle breeds were genetically characterized by using DNA markers. The characterization of Bulgarian cattle local breeds with microsatellite loci is useful to identify high informative markers for each breed while simultaneously would facilitate the genotypic identification. All loci were polymorphic and this indicates that the microsatellite markers used are suitable for genetic diversity study. The comparison between the two local breeds shows that they display a remarkable high variability. This clearly suggests that these breeds have potential value to be preserved as genetic resources. The highest value of Bulgarian local breeds is determined of the genes they possess as a source of their excellent adaptive capabilities, high resistance to diseases and ability of good meat and milk quality. More work and analysis will be required in the future to increase the efficiency of studying a larger number of microsatellites. Additional information on productive, morphological, and fitness-related traits of these breeds is needed, however, as these factors should also be taken into account when ranking breeds for preservation purposes. (author)

[en] Alpacas from Puno, Junin and Huancavelica were analysed by a panel of 10 microsatellite markers in order to determine the level of genetic diversity among these populations. A sample of two hundred and sixty five non-related alpacas showed allelic polymorphism identifying a total of 144 microsatellite alleles. Alleles number ranged from 6 (YWLL40) to 28 (YWLL08), with a mean number of alleles per locus (MNA) of 14.40. The polymorphic information content ranged from 0.635 (YWLL40) to 0.942 (YWLL08) with a mean of 0.7975, while expected heterozygosity (H_E) ranged from 0.692 (YWLL40) to 0946 (YWLL08) with a mean of 0.8207. All loci except LCA37 (heterozygote deficit, P < 0.01) were in HWE and all populations except one from Munani - Puno (heterozygote deficit P < 0.01) were in HWE. All population pairs were genic and genotypic differentiation (exact G test) except for two Junin populations (P < 0.01). The relative magnitude of gene differentiation among populations was evaluated with F-statistics, frequency of private alleles and number of migrants. FIS value for all populations was 0.014 (Rho_IS = 0.015) with the highest value of 0.046 for Sector Carniceria B - Huancavelica. No significant (P > 0.01) inbreeding effect (FIS) was detected in alpaca populations. FIT value was 0.037 (Rho_IT = 0.0318) for all population and FST value for all populations was 0.024 (Rho_ST = 0.0171). A F_ST value of 0.024 (P < 0.01), implied that 97.6% of the total genetic variation was from genetic differentiation within each population and only 2.4 % of the genetic variation existed among populations. Two populations from Huancavelica (Sector Pallccapampa and Sector Carniceria A) have highest F_ST value (0.753) and RhoST (0.736) with a frequency of private alleles of 0.0207 and number of migrants of 7.8359 in all alpaca populations. A Neighbor-joining tree was constructed based in Nei's genetic distance D_A and standard genetic distance D_S using DISPAN software. Four cluster were identified: Junin (Cochas and Pachacayo), Puno (Munani and Lacchoc), Huancavelica 1 (Sector Carniceria A) and Huancavelica 2 (Sector Pallccapampa). Individual assignment test and Bayesian clustering analysis were used to evaluate population structure using Structure v2.2 software. Structure analysis showed three clusters: (i) Sector Carniceria A - Huancavelica, (ii) Sector Pallccapampa - Huancavelica (include Sector Carniceria B) and (iii) Junin - Puno (include Cochas, Pachacayo from Junin, Munani from Puno and Lacchoc from Huancavelica). Substancial genetic differentiation between Huancavelica with Junin and Puno were found. The preliminary results showed that alpaca populations in Peru maintained high genetic diversity within populations and a low, although significant, genetic differentiation between populations. (author)

[en] In a study of ataxia-telangiectasia (A-T) in the UK, patients in10 out of 60 families were shown to have a much lower level of chromosomal radiosensitivity compared with the majority of patients. In some patients the level of radiosensitivity was hardly distinguishable from normal. Patients in this group, however, could be distinguished clinically from the majority either by the later onset of severe cerebellar features or the slower rate of progress of the disorder. By using highly polymorphic microsatellite repeat markers a chromosome 11q22-23 haplotype common to the majority of these patients, and not occurring in any non-A-T chromosome in 60 families, was identified on one chromosome. The haplotype probably defines the region of the A-T gene in these families and the mutation associated with this haplotype may be much less severe than the second mutation thereby producing the slightly milder phenotype. (author)

[en] Powassan virus (POWV, Flaviviridae: Flavivirus) is the sole North American member of the tick-borne encephalitis complex and consists of two distinct lineages that are maintained in ecologically discrete enzootic transmission cycles. The underlying genetic mechanisms that lead to niche partitioning in arboviruses are poorly understood. Therefore, intra- and interhost genetic diversity was analyzed to determine if POWV exists as a quasispecies in nature and quantify selective pressures within and between hosts. In contrast to previous reports for West Nile virus (WNV), significant intrahost genetic diversity was not observed. However, pN (0.238) and d_N/d_S ratios (0.092) for interhost diversity were similar to those of WNV. Combined, these data suggest that purifying selection and/or population bottlenecks constrain quasispecies diversity within ticks. These same selective and stochastic mechanisms appear to drive minor sequence changes between ticks. Moreover, Powassan virus populations seem not to be structured as quasispecies in naturally infected adult deer ticks.

[en] Arboviruses such as Zika virus (ZIKV, Flaviviridae; Flavivirus) must replicate in both mammalian and insect hosts possessing strong immune defenses. Accordingly, transmission between and replication within hosts involves genetic bottlenecks, during which viral population size and genetic diversity may be significantly reduced. To help quantify these bottlenecks and their effects, we constructed 4 “barcoded” ZIKV populations that theoretically contain thousands of barcodes each. After identifying the most diverse barcoded virus, we passaged this virus 3 times in 2 mammalian and mosquito cell lines and characterized the population using deep sequencing of the barcoded region of the genome. C6/36 maintain higher barcode diversity, even after 3 passages, than Vero. Additionally, field-caught mosquitoes exposed to the virus to assess bottlenecks in a natural host. A progressive reduction in barcode diversity occurred throughout systemic infection of these mosquitoes. Differences in bottlenecks during systemic spread were observed between different populations of Aedes aegypti.

[en] A theoretical model for Open-Nucleus Systems is herein described in the case of beef cattle breeding. One of the starting points is the observation that the majority of the standard theoretical models for open-nucleus breeding systems were constructed for the case of discrete generations, i.e. for the cases in which the dam average fertility coefficient is f>2. In the case of cattle herds, when only a fraction of the breeding dams can be replaced, it is therefore worthwhile to build up anew a rather rigorous theoretical model, with overlapping generations, and check its predictions. Namely, we apply the new formulae - explicitly depending on β_F, ν_F, ν_M, K and R - to the system in which all breeding sires are in the Nucleus (and are reared in the nucleus itself), and are mated to both Nucleus and Base dams via artificial insemination. Optimal system design has been looked for by the NAG and MINOS computation programs, operated on Vax computers. Opening the nucleus in this situation results to be very effective since the (optimum) asymptotic genetic gain per generation for ''closed nucleus'' systems (x=0) results to be, when e.g. R≡F/M≅200, more than 40% lower than the (optimum) asymptotic genetic gain, G*, for open nucleus systems. Optimal design corresponds to: (i) having a fraction p≅16% of the female population in the nucleus; (ii) replacing practically all the (nucleus) breeding sires by the best (nucleus born) males: ν_M=97/98%; (iii) using for dam replacement all (b≅100%) the (base and nucleus born) females; (iv) implementing a high upward gene migration (x≅80%), while all the surplus nucleus-born females are to be used as base replacements. This corresponds to replace, at each generation, also almost all the nucleus dams (ν_F≅95/100%), and the largest possible fraction of base dams (β_F≅30%, a value changing with p). 17 refs

[en] There are several variants of ataxia-telangiectasia (A-T): classical A-T with marked radiation sensitivity; classical A-T with intermediate levels of radiation sensitivity; mild A-T with intermediate levels of radiation sensitivity; A-T without telangiectasia; A-T without oculomoto apraxia; and A-T with microcephaly. These disorders are probably caused by different allelic mutations, because affected sibs resemble the index patients, and because there is an association of certain haplo-types of 11q22-23 with specific phenotypes. The Nijmegen Breakage Syndrome, with its lack of ataxia, seems on clinical grounds to be a different disorder. Although A-T is almost always inherited as an autosomal recessive, there are some unusual features; an unexpectedly low parental consanguinity rate, an incidence in sibs that is < 0.25, and occurrence of disease in many different races and in the offspring of mixed race unions. Moreover, looking at haplotypes from 63 UK patients, there is a remarkably low incidence of homozygosity. An autosomal recessive condition that is deficient in parental consanguinity, and in homozygosity for the region around the gene, can be explained by J.H. Edwards' hypothesis that homozygosity for alleles at a neighbouring locus are lethal early in embryogenesis. Other possible mechanisms to explain the unusual genetic features are discussed. (author)

[en] In order to discover genetic variation of gliadin composition of wheat varieties in Shanxi, A-PAGE method was used to analyze difference of gliadin composition and genetic diversity of 214 varieties including local bred, introduced and landraces wheat in recent 40 years. The results were as follows: number of gliadin band increased by 2.1 and 1.5 in bred and introduced wheat varieties compared to Shanxi landraces. In total 70 bands,the frequency of 26 bands detected from bred and introduced cultivars was up, 23 down, 21 no regular pattern compared to Shanxi landraces. In 4 gliadin zones, variation of types and frequency of gliadin band in ω zone was largest, γ was the second, β and α was smallest. Two band block of 16.5 and 19.1, and three band block of 12.9, 15.7 and 17.8 were tested in ω zone, but they do not express in the same variety. Mean of genetic distance in Shanxi wheat landraces was larger than those in other two type wheat cultivars. The cluster analysis found that cultivars of landraces, bred or introduced were divided into the same group, which showed genetic difference of loci encoded gliadin in Shanxi wheat landraces was larger than the other two type wheat cultivars, namely, the level of genetic variation of gliadin in bred or introduced cultivars was not high in the last 40 years. (authors)

No abstract available

[en] This study was undertaken to determine the genetic structure and diversity among two local cattle breeds from Bulgaria, the Rhodope Shorthorn and Grey cattle. A panel of 11 microsatellites was used for the evaluation. For these loci, allele frequencies, heterozygosity, HWE, genetic disequilibrium were determined. Both populations displayed a relatively high level of genetic variation as estimated by allelic diversity and heterozygosity. Heterozygosities ranged from 0.5424 (SPS 115) to 0.8983 (TGLA 227) for the Rhodope population and from 0.6333 (TGLA 53) to 0.9333 (TGLA227) for Grey cattle, with similar average values for the two groups (0.7858 and 0.7757). These results clearly suggest that these breeds are suitable to preserve as genetic resources. (author)