Genetic Distribution of Five Spinocerebellar Ataxia Microsatellite Loci in Mexican Native American Populations and Its Impact on Contemporary Mestizo Populations

Spinocerebellar ataxias (SCAs) conform a heterogeneous group of neurodegenerative disorders with autosomal dominant inheritance. Five of the most frequent SCAs are caused by a CAG repeat expansion in the exons of specific genes. The SCAs incidence and the distribution of polymorphic CAG alleles vary among populations and ethnicities. Thus, characterization of the genetic architecture of ethnically diverse populations, which have undergone recent admixture and demographic events, could facilitate the identification of genetic risk factors. Owing to the great ethnic diversity of the Mexican population, this study aimed to analyze the allele frequencies of five SCA microsatellite loci (SCA1, SCA2, SCA3, SCA6, and SCA7) in eleven Mexican Native American (MNA) populations. Data from the literature were used to compare the allelic distribution of SCA loci with worldwide populations. The SCA loci allelic frequencies evidenced a certain genetic homogeneity in the MNA populations, except for Mayans, who exhibited distinctive genetic profiles. Neither pathological nor large normal alleles were found in MNA populations, except for the SCA2 pre-mutated allele in the Zapotec population. Collectively, our findings demonstrated the contribution of the MNA ancestry in shaping the genetic structure of contemporary Mexican Mestizo populations. Our results also suggest that Native American ancestry has no impact on the origin of SCAs in the Mexican population. Instead, the acquisition of pathological SCA alleles could be associated with European migration.

Modeling the technology of identification of wine materials and wines by PCR analysis of microsatellite loci of grapevine chloroplast DNA

Использование полиморфных микросателлитных локусов ДНК является одним из подходов к аутентификации виноматериалов и вин. При этом SSR-маркеры хлоропластной ДНК имеют большую копийность мишени на клетку и менее подвержены деградации из-за содержания в органеллах с двойной мембраной. Целью настоящей работы являлось моделирование технологии идентификации виноматериалов и вин ПЦР-анализом микросателлитных локусов хлоропластной ДНК винограда. Подобраны условия экстракции нуклеиновых кислот, постановки ПЦР с соответствующими наборами праймеров и электрофоретической детекции, направленные на практическое воспроизведение генетического тестирования пробоподготовленного биоматериала из осаждаемого винного дебриса. Представлены наглядные результаты выравнивания частичных нуклеотидных последовательностей аллелей микросателлитных локусов хлоропластной ДНК Vitis vinifera L. Проанализирована разделяющая способность метода горизонтального электрофореза в геле «Spreadex EL 300» in silico моделированием генерируемых аллельспецифичных фрагментов, позволяющая идентифицировать известные хлоротипы винограда даже при постановке ПЦР с ограниченными наборами праймеров, нацеленных на локусы cpSSR3, cpSSR5, cpSSR10, NTCP12 и ccSSR9. The use of polymorphic microsatellite DNA loci is one of the approaches to the authentication of wine materials and wines. At the same time, SSR markers of chloroplast DNA have a large target copy number per cell and are less susceptible to degradation due to their content in organelles with a double membrane. The aim of this work was to simulate the technology of identification of wine materials and wines by PCR analysis of microsatellite loci of grapevine chloroplast DNA. The conditions for the extraction of nucleic acids, PCR with the corresponding sets of primers and electrophoretic detection were selected, aimed at the practical reproduction of genetic testing of the sample prepared biomaterial from the precipitated wine debris. Illustrative results of the alignment of partial nucleotide sequences of alleles of microsatellite loci of Vitis vinifera L. chloroplast DNA are presented. The separating ability of the method of horizontal electrophoresis in «Spreadex EL 300» gel by in silico modeling the generated allele-specific fragments, which makes it possible to identify the known chlorotypes of grapevine with a limited set of primers targeting loci (cpSSR3, cpSSR5, cpSSR10, NTCP12 and ccSSR9) has been analyzed.

Analysis of the polymorphism of microsatellite loci in Picea abies (L.) H. Karst. and Picea obovatа Ledeb populations

Процессы генезиса хвойных лесов интенсивно изучаются с использованием методов молекулярного маркирования. Микросателлитные локусы рассматриваются в качестве наиболее полиморфной и воспроизводимой системы кодоминантных молекулярных маркеров. В цели исследования входило установить возможность использования микросателлитных маркеров для определения видовых различий между елью европейской и сибирской (Picea abies и Picea obovatа), а также оценить степень генетической обособленности региональных популяций ели на территории Европейской части РФ. Исследование показало, что использование набора из двенадцати микросателлитных маркеров позволяет разделить выборку елей, собранных с европейской и азиатской частей страны, на два генетических кластера, соответствующих видам Picea abies и Picea obovatа. Проанализированные в исследовании микросателлитные локусы могут быть использованы для оценки генетического разнообразия и географического происхождения ели европейской и сибирской. The processes of genesis of coniferous forests are widely investigating using molecular markers. Many studies are based on the analysis of microsatellite loci, which are acknowledged as the most reproducible and polymorphic co-dominant molecular markers. This study is aimed to establish the possibility of using microsatellite markers to determine differentiation between Norway and Siberian spruce (Picea abies and Picea obovata). Another task of this research was to assess the degree of genetic isolation of regional spruce population in the territory of European part of the Russian Federation. This study shows that using a large number of microsatellite markers allows to divide the sample of spruce collected from European part of Russia and Siberia in two genetic clusters, corresponding to Picea abies and Picea obovata. The microsatellite loci analyzed in the study can be used to assess genetic diversity and geographic origin of spruce trees and determine the origin of wood and planting material of Norway and Siberian spruce.

Correlations between microsatellite DNA heterozygosity and reproductive traits in Large White sows

The main aim of this paper was to determine whether heterozygosity (assessed using microsatellite genotypes) was correlated with the reproductive traits in sows. The study was conducted on two herds of sows of the Large White sows breed at the Limited Liability Company “Tavriys’ki svyni” (Kherson region, Ukraine) and the Agricultural Private Enterprise “Techmet-Yug” (Mykolayiv region, Ukraine). During the study, we used eleven microsatellite loci recommended by International Society for Animal Genetics (ISAG) – S0101, S0155, S0228, S0355, S0386, Sw24, Sw72, Sw240, Sw857, Sw936 and Sw951. The litter records included information on the total number of piglets born (TNB), number of piglets born alive (NBA), number of stillborn piglets (NSB), frequency of stillborn piglets (FSB), litter size at weaning (NW) in the first five parities. Individual heterozygosity estimates (for each microsatellite loci separately) and microsatellite multilocus heterozygosity (for all used loci) estimates (MLH) were used in our analysis. ANOVA was used to determine the relationship of the dependent effects (reproductive traits) to single locus heterozygosity using two classes: 0 (for homozygous individuals) and 1 (for heterozygous individuals). In addition, the following indicators were calculated for each genotype: the squared distances (d2) between alleles within an individual for each microsatellite loci and mean squared distances (mean d2) between alleles within an individual for 11 microsatellite loci. Spearman’s rank correlation coefficients were used to measure the association between d2 (for each microsatellite loci) and reproductive traits in sows. ANOVA on reproductive traits of sows belonging to different MLH and mean d2 classes was also undertaken. For sows from the Agricultural Private Enterprise “‘Techmet-Yug” were observed negative associations between heterozygosity and reproductive traits. We conclude that care should be taken when crossing between different breeders (English and Hungarian selection) to avoid outbreeding depression.

Rich diversity in cultivated Finnish potato onions (Allium cepa var. aggregatum G. Don)

Potato onion (Allium cepa var. aggregatum G. Don) remained the most widely grown onion type in Finland up to the 1950’s, after which the more productive cultivars of common onion replaced this vegetatively propagated onion type. The Finnish accessions have been maintained in two national plant genetic resources (PGR) collections since 1990’s but new samples have been obtained still later. In this research, we analysed the genetic diversity of potato onions and shallots, grown in home gardens and in PGR collection, and compared the uniformity of the two PGR collections. One hundred ten onion samples were analysed using eight microsatellite loci, which amplified 83 alleles in total. There was a large number of genetically different samples, forming four major groups in the dendrogram. The results show that there is still a lot of genetic diversity among the Finnish potato onions, even though they are propagated vegetatively. The rich diversity in the samples obtained from citizens reflects a valuable source of genetic resources maintained by home gardeners. The national collection has been updated on the basis of the results. To ensure the preservation of the rich onion heritage, efforts are needed to increase the availability of potato onion to home gardeners and commercial growers.

Population genetics of Anopheles arabiensis, the primary malaria vector in the Republic of Sudan

Background Anopheles arabiensis is a member of Anopheles gambiae complex and the main malaria vector in Sudan. There is insufficient population genetics data available on An. arabiensis for an understanding of vector population structure and genetics, which are important for the malaria vector control programmes in this country. The objective of this investigation is to study the population structure, gene flow and isolation by distance among An. arabiensis populations for developing control strategies. Methods Mosquitoes were collected from six sites located in three different states in Sudan, Khartoum, Kassala and Sennar, using pyrethrum spray catch of indoor resting mosquitoes. Anopheline mosquitoes were identified morphologically and based on species specific nucleotide sequences in the ribosomal DNA intergenic spacers (IGS). Seven published An. gambiae microsatellite loci primers were used to amplify the DNA of An. arabiensis samples. Results PCR confirmed that An. arabiensis was the main malaria vector found in the six localities. Of the seven microsatellite loci utilized, six were found to be highly polymorphic across populations, with high allelic richness and heterozygosity with the remaining one being monomorphic. Deviation from Hardy–Weinberg expectations were found in 21 out of 42 tests in the six populations due to heterozygote deficiency. Bayesian clustering analysis revealed two gene pools, grouping samples into two population clusters; one includes four and the other includes two populations. The clusters were not grouped according to the three states but were instead an admixture. The genetic distances between pairs of populations ranged from 0.06 to 0.24. Significant FST was observed between all pairwise analyses of An. arabiensis populations. The Kassala state population indicated high genetic differentiation (FST ranged from 0.17 to 0.24) from other populations, including one which is also located in the same state. High gene flow (Nm = 1.6–8.2) was detected among populations within respective clusters but limited between clusters particularly with respect to Kassala state. There was evidence of a bottleneck event in one of the populations (Al Haj Yousif site). No isolation by distance pattern was detected among populations. Conclusions This study revealed low levels of population differentiation with high gene flow among the An. arabiensis populations investigated in Sudan, with the exception of Kassala state.

Integrative taxonomy of two thrush complexes (Aves: Turdidae) reveals introgression across sister species

The classification of some Turdus species, such as the Naumann’s and dusky thrush complexes and the red-throated and black-throated thrush complexes, is controversial. Herein, we used molecular data (mitochondrial genes and microsatellite loci) and morphological characters to review the taxonomy of these thrush complexes and analyze the genetic differentiation between them. Our phylogenetic analysis based on mitochondrial genes indicated that all haplotypes could be divided into two reciprocally monophyletic sister clades corresponding to these two thrush complexes. The same results were revealed by coalescence-based species delimitation. Therefore, these two thrush complexes should be divided into two separate species (T. naumanni and T. ruficollis) and include two subspecies per species according to combined characters from morphological analyses and multilocus approaches. The above classifications were also supported by an analysis of genetic differentiation between T. naumanni and T. ruficollis and within each species. Moreover, there was significant mixing between these two thrush species in the neighbor-joining (NJ) tree and the cluster analysis of microsatellite loci. This led to a pattern of nuclear-mitochondrial discordance between the two species. This could be the result of extensive nuclear introgression between these two sister species. We also provide a potential explanation for the mechanism of gene introgression and nuclear-mitochondrial discordance between the two bird species.

Ampelographic and molecular characterisation of grapevine varieties in the gene bank of the experimental vineyard ‘Radmilovac’ – Serbia

Characterisations of thirty grapevine varieties (Vitis vinifera L.) from the experimental vineyard ‘Radmilovac’ were conducted using a large number of OIV descriptors and eight highly polymorphic microsatellite loci. The ampelographic description contained 45 features. Molecular characterisation of selected microsatellite loci was performed using capillary electrophoresis fragment analysis. Dendrograms based on ampelographic and genetic data resulted in three groups of varieties. Qualitative ampelographic characteristics tended to manifest significant differences. The most common deviation among varieties within the group was in the characteristic OIV 051 (colouration of the upper side of a young leaf). Genetic characterisation of SSR markers through analyses of a large number of varieties contributes to better organisation of grapevine collections and simpler identification of varieties, as well as data exchange. When identifying the varieties, the results of the DNA analysis should be combined with the ampelographic descriptors, in order to select grapevine varieties with desirable viticultural and oenological traits. Integration of the obtained genetic data with the ampelographic data is of utmost importance for accurate identification of the varieties and offers a significant means for the preservation and use of the varieties.

Formation of Potential Heterotic Groups of Oat Using Variation at Microsatellite Loci

An evaluation of polymorphism at the microsatellite loci was applied in distinguishing 85 oat (Avena sativa L.) genotypes selected from the collection of genetic resources. The set of genotypes included oats with white, yellow, and brown seeds as well as a subgroup of naked oat (Avena sativa var. nuda Koern). Variation at these loci was used to form potential heterotic groups potentially used in the oat breeding program. Seven from 20 analyzed microsatellite loci revealed polymorphism. Altogether, 35 microsatellite alleles were detected (2–10 per locus). Polymorphic patterns completely differentiated all genotypes within the subgroups of white, brown, and naked oats, respectively. Only within the greatest subgroup of yellow genotypes, four pairs of genotypes remained unseparated. Genetic differentiation between the oat subgroups allowed the formation of seven potential heterotic groups using the STRUCTURE analysis. The overall value of the fixation index (Fst) suggested a high genetic differentiation between the subgroups and validated a heterotic grouping. This approach can be implemented as a simple predictor of heterosis in parental crosses prior to extensive field testing or development and implementation of more accurate genomic selection.

Patterns of Connectivity and Isolation in Marine Populations

<p>There is ongoing debate about the levels of connectivity among marine populations and despite its importance, there is limited information on the levels of population connectivity in most geographic locations. This lack of information severely limits our ability to adequately manage the marine environment including the design and implementation of Marine Reserve (MRs) networks. The specific objectives of this thesis were to: 1) Develop polymorphic microsatellite loci for my model species, the intertidal gastropod Austrolittorina cincta; 2) Conduct population genetic studies across A.cincta populations within the Cook strait region to asses the levels of connectivity within the regional marine reserve network; 3) Determine the levels of A. cincta larval movement and settlement from an isolated source; and 4) Asses the effect of the larval abundance on settlement rates. This thesis includes laboratory studies; population genetic studies; and field surveys within New Zealand and in the Wakatobi National Park, Indonesia. Eight novel polymorphic microsatellite loci were developed for A. cincta and five of these loci were used to investigate population connectivity across seven populations within the Cook Strait region, including four marine reserves. In the population genetics study, in contrast to what was expected, I recorded low, but significant genetic differentiation between most population pairs within the Cook Strait region, over a minimum and maximum spatial scale of 55 to 300 km, including several of the MRs. In a large-scale field settlement survey on the Kapiti coast combined with the use of microsatellite markers I investigated A. cincta larval movement and settlement and found that most larvae settle within 5 km, although some larvae might travel up to 50 km. Finally, the coral settlement studies in the Wakatobi National Park revealed lower coral settlement rates at sites with low adult coral cover, suggesting an effect of the the amount of local available larvae on coral settlement rates. While it has been suggested that marine populations are demographically open, with larvae connecting populations separated over large spatial scales, this thesis shows that populations might not be as open as previously considered and localized dispersal and self-recruitment processes might be a frequent feature in marine populations. This thesis provides valuable information to managers about marine reserve networks and the importance of adequate environmental protection to ensure future viable populations.</p>