Loci Est-2 Research Articles

Analysis of the genetic structure of Ukrainian carp breeds using protein markers

Goal. To characterize the features of the genetic structure of scaly and frame carps of the Antoninskyi-Zozulenetskyi intrabreed type according to protein and enzyme systems. Methods. Laboratory studies, computer statistical analysis. Results. The genetic structure of the Antoninskyi-Zozulenetskyi intrabreed type of scaly and frame carp was studied by protein markers. Species-specific features of the genetic structure of the studied loci were revealed. The level of available and expected heterosis readiness was calculated. It was established that the increased allelic and genotypic diversity of the genetic structure can be caused by a slightly increased intensity of the selection work. The detected excess of heterozygotes at individual loci indicated the presence of stabilization processes of the genetic structure. Conclusions. Breed-specific features of the genetic structure of the Antoninskyi-Zozulenetskyi intrabreed type of scaly and frame carp breeds were revealed. A certain genetic differentiation was observed for individual protein markers, as well as a predominance of the actual level of average heterozygosity for all loci over the expected one. It was established that the TF, ALB, and EST loci belonged to polymorphic systems, and the SR, AMI, PN, and HB loci belonged to monomorphic systems.

GENETIC CHARACTERISTICS OF PADDLEFISH (POLYODON SPATHULA (WALBAUM, 1792)) BROOD STOCKS

GENETIC CHARACTERISTICS OF PADDLEFISH (POLYODON SPATHULA (WALBAUM, 1792)) BROOD STOCKS

Demography and esterase polymorphism of brazilian populations of Zaprionus indianus (Diptera: Drosophilidae) from the Brazilian Cerrado localities

Zaprionus indianus (fig fly) is a drosophilid of African origin that was recorded in Brazilian territory in 1999, quickly dispersing throughout the country, causing impacts on fig culture, and becoming one of the dominant Drosophilidae species in the Cerrado biome. Due to the fact it is an invasive species and a potential pest in fruit cultivars, it is essential to monitor the variations in the populations of this species aiming to verify its genetic and demographic structure and possible impacts on the drosophilid community. The demography and the genetic data obtained from the Est3 polymorphism of fig fly have been evaluated in six populations of Brazilian Cerrado sampled during the dry season. Multivariate analyses of PCA, UPGMA and landscape genetics were performed. The results have indicated variation in the demography of the sampled populations, the presence of two alleles (Est31 and Est34) in all of them, and a higher isolation degree of the Guaíra (SP) population. Thus, the fig fly is a colonizer of the Brazilian Cerrado, and the polymorphisms of Est3 locus are an appropriate genetic marker to investigate the bioinvasion process.

EST-Microsatellite Types and Structural Scenarios in European Hake Fisheries.

Simple SummaryThe conservation of the maximum genetic background from all genomic regions matters for sustainability in the changing global scenario. This study focused the importance of integrating such genetic variation in order to infer meaningful units for management and sustainability. We show that knowledge that can be obtained from different marker types should be goal-oriented, i.e., remnant patterns of selection pressures and extreme drift episodes (directional markers, i.e., the evolutionary genetic background), current evolutionary novelty and adaptive potential for fisheries’ sustainability (balanced markers, i.e., the potential genetic drive of the species), and demographic dynamics of genetic relevance for fisheries’ management (neutral markers, i.e., the present-day fishery structure and connectivity). In particular, special attention should be paid to the variation in supergenes or balancing markers, which are a rich source of evolutionary novelty and can be crucial for species welfare and survival.A fishery’s structure and connectivity are priors to its effective management. A successful description of such processes depends on both the sampling design and the choice of adequate genetic markers. EST markers are perfusing the studies of marine metapopulations and are believed to provide access to functional polymorphisms. However, the assumed adaptive role of outlier EST loci might not be generalizable. EST-microsatellites represent the upper polymorphic boundary in these regions because of their high mutation rate. We have subclassified the polymorphisms of EST-microsatellites to assess their structural contribution in the European hake, a paradigmatic and highly mobile marine species (HMMS). Because of the counterbalanced forces between directional markers (15%) and balanced markers (23%), the whole marker set offers the same structural situation as the one observed with neutral markers (62%), i.e., k = 2 gene pools. In contrast to outlier EST- microsatellites, neutral EST subsets allow one to measure crucial population phenomena for fisheries’ management. The high inter-population divergence of outlier EST-microsatellites is compatible with drifted post-selection genomic regions rather than with ongoing local selective pressures. The structural scenario in hake is explainable by a limited gene flow across the Almería-Oran Front (AOF) and by the within-basin IBD pattern of connectivity plus drift-related demographic events. This study highlights how polymorphic properties of EST-microsatellite types can be useful to address mutually excluding research tasks in fisheries, i.e., to address its evolutionary history (directional markers or FAPS: Fossil Adaptive Polymorphic Systems); to delineate management units (neutral markers or NAPS: Non Adaptive Polymorphic Systems); or to ensure sustainability (balanced markers or APS: Adaptive Polymorphic Systems).

ASSESSMENT OF THE GENETIC VARIABILITY OF DIFFERENT AGE GROUPS OF SILVER AND BIGHEAD CARPS BY BIOCHEMICAL POLYMORPHISM

Goal. The study aimed to analyze and assess the genetic variability of different age groups of silver and bighead carps by the polymorphism of protein and enzyme systems.
 Methods. Blood samples were taken from silver (Hypophthalmichthys molitrix) and bighead (Aristichthys nobilis) carps of "Sunpoint Ukraine" LLC, Slobozhanske, Zmiiv district, Kharkiv region.
 Blood from the tail vein was collected from age-2 and age-3 fish in vivo and placed into tubes with an anticoagulant. Whole blood samples were separated into fractions by centrifugation and as a result plasma and erythrocytes were packed into separate tubes. The methods of vertical polyacrylamide and horizontal starch electrophoresis were used for the electrophoretic separation of proteins and enzymes of silver and bighead carps blood. Histochemical staining of the gel plates was carried out with t) and bighead he following genotyping of allelic variants of protein and enzyme systems. Biochemical systems such as loci of prealbumin (Pralb), esterase (EST, K.F. 3.1.1.1), malate dehydrogenase (MDH, K.F. 1.1.1.37), enzyme malic (ME, K.F. 1.1.1.40) and carbonic anhydrase (CA, K.F. 4.2.1.1) were investigated. Statistical processing of experimental data was performed using Biosys-1. Cluster analysis was carried out using MEGA-X.
 Results. Analysis of the peculiarities of the distribution of allele frequencies and the genotypic composition of Pralb, EST, MDH, ME, and CA loci was carried out in the age-2 and age-3 groups of silver and bighead carps. The prevalence of the frequency of the fast migrating allelic variant F was revealed in comparison with the slow migrating gene at EST locus in the age-3 group of silver carp (Est F = 0.620). The prevalence of the frequency of the fast allelic variant Pralb A in comparison with the slow Pralb B was observed in the silver carp groups (Pralb A = 0.812 in the age-2 and Pralb A = 0.726 in the age-3 groups. According to the genotypic composition of the studied loci, there was an excess of heterozygous individuals in the age-2 group of silver carp, which indicates their genetic imbalance. The formation of breeding stocks of silver and bighead carps requires control of the level of genetic variability of different age groups to monitor changes in the genetic structure and maintain the optimal level of heterozygosity in stocks. The highest level of average heterozygosity (79.4%) was found in the age-2 group of silver carp, which prevailed over the expected average heterozygosity with a value of 49.4%. In comparison with other studied groups, the age-2 group of bighead carp had the lowest level of average heterozygosity of 59.1% versus the theoretically calculated level of 45.5%. The age-2 and age-3 groups of bighead carp had the highest level of heterozygosity at Ca locus at the level of 82.8 and 78.6% respectively, in contrast to the expected heterozygosity at this locus at the level of 49.9 and 49.7%. A dendrogram of the genetic relationships of different age groups of silver carp was constructed based on the values of genetic distances. The formed clusters indicated the formation of the genetic structure of the silver and bighead carps by species affiliation.
 Conclusions. The analysis of the genetic structure of different age groups of the silver and bighead carps was performed by the polymorphism of protein and enzyme systems such as Pralb, EST, MDH, ME, CA loci. The study describes the features of the distribution of allelic frequencies and genotypic variants of the aforementioned loci. The level of average heterozygosity, observed and expected heterozygosity at loci in age-2 and age-3 groups of silver and bighead carps were determined. The high genetic variability of an age-2 group of silver carp at the level of 79.4% indicates the need to stabilize their genetic structure. As a result of the cluster analysis, it was determined that the formation of the genetic structure of the silver carp groups of the "Sunpoint Ukraine" farm in the Kharkiv region occurs by species affiliation. The study and use of biochemical markers will allow differentiating stocks of silver and bighead carps. As well as in complex analysis with other molecular genetic markers will allow them to develop a genetic passport.

“Est locus, aestifero” (Carm. 1.18) as an Example of the Locus Amoenus Topos in the Poetry of Venantius Fortunatus

The Polish version of the article was published in Roczniki Humanistyczne vol. 61, issue 3 (2013).
 In this article the author presents the poem “Est locus, aestifero,” which appeared in the first book of Carmina, against the background of the topic of locus amoenus in the poetry of Venantius Fortunatus. The poem has 18 lines and is written in elegiac meter. It is a description of the village (country estate) of Bissonum, near Bordeaux. The ekphrasis, into which are woven the elements of the topic we are interested in, is combined with a very clear motif of laudation. This is a characteristic feature of Venantius Fortunatus’ poetry. The English translation of the poem is an integral part of the essay.

Aloenzimna genetichna harakteristika na pchelni semeystva Apis mellifera (Hymenoptera: Apidae) ot Bulgaria s razlichno higienno povedenie

The genetic variability in 25 honey bee colonies from different regions of Bulgaria with diverse hygienic behaviour (super hygienic, hygienic and non-hygienic) has been studied. Alloenzyme analysis of two systems (MDH-1 and EST-3) corresponding to 2 loci was used in order to characterize the colony polymorphism. Totally 1,150 worker bees were included in this investigation. MDH-1 locus was found to be polymorphic in all of the studied colonies, having two alleles – MDH-165 and MDH-1100. The EST-3 locus was fixed in ten of the investigated colonies. Polymorphism with total presence of four alleles of this locus (EST-380, EST-388, EST-3100 and EST-3118) was found in the other studied colonies. The calculated polymorphism was between 50% and 100%. The observed and expected heterozygosities (Ho and He) ranged from 0.296 to 0.354 and from 0.280 to 0.332 in non-hygienic and super hygienic groups, respectively. The calculated mean observed and expected heterozygosities were 0.320 and 0.307, respectively. The calculated Fst and Nm levels demonstrated lower differentiation between super hygienic and hygienic colonies and higher differentiation between super hygienic and non-hygienic colonies. Dissimilarities between levels of polymorphism, heterozygosity, Fst, Nm and allele frequencies in the studied groups of colonies with different hygienic behaviour were found and discussed. The results of the present study provide new information concerning relations between hygienic behaviour and allozyme characteristics which could be used for future selection with honey bees in Bulgaria.

Esterase Profile in Drosophila mercatorum pararepleta (Diptera; Drosophilidae), a Non-cactophilic Species of the repleta Group: Development Patterns and Aspects of Genetic Variability.

Luciana Paes de Barros Machado, Natalia Silva Alves, Jaqueline de Oliveira Prestes, Gabriela Ronchi Salomón, Daiane Biegai, Thais Wouk, and Rogério Pincela Mateus (2017) Esterases are a diversified group of isozymes that performs several metabolic functions in Drosophila. In the D. repleta group, this class of enzymes was well described in cactophilic species, existing a lack of studies considering substrate speci city and life cycle expression in the non-cactophilic species. The larvae of cactophilic species of the D. repleta group develop in rotting cacti cladodes, but adults are generalists. Thus, different patterns expression can be found for esterases throughout development. In this work we analyzed esterase pro le and substrate speci city during development, and genetic variability aspects in D. mercatorum pararepleta, a non-cactophilic and generalist species of D. repleta group that was understudied hitherto. Samples of 3rd (F3) and 104th (F104) generations of three D. mercatorum pararepleta strains, obtained after collections in xerophytic enclaves of southeastern Brazil (ITI and SER in São Paulo state and RIP in Paraná state), and of D33 strain (obtained from Cristalina-GO, Midwest of Brazil, and established in the laboratory in 1987) were analyzed. Eight esterase loci, EST-1 to EST-8, were detected. EST-1 and EST-2 were adult exclusive. Only EST-3 and EST-8 were monomorphic; all the others presented between two (EST-6) and six (EST-7) alleles. EST-7 was the only dimeric locus and also the only one that showed to be a preferably β-esterase regarding affinity to α- and β-naphthyl acetates as substrates. The other seven loci were divided into three classes: α-esterase exclusive (EST-2); preferably α-esterase (EST-3, EST-4, EST-5 and EST-8); and α/β-esterase (EST-1 and EST-6). The EST-3, EST-5 and EST-6 loci were not detected in all samples, suggesting that they could have become pseudogenes due to the mutation accumulation after the gene duplication. The allele frequency of EST-7 locus, which showed the highest number of alleles, in adults of D33 and SER-F3 evidenced a higher variability and diversity in the oldest strain (six alleles, Ho = 0.46) than in the youngest ( five alleles, Ho = 0.26). Moreover, the analysis of SER-F104 revealed that this locus became monomorphic. The higher variability in the strain established in the laboratory at least two decades ago, together with the allele fixation in the SER-F104, indicate that the SER strain probably suffered a more severe action of founder effect/bottleneck when it was established in the laboratory and, therefore, even if the maintenance afterwards was performed using a high number of individuals, it did not assured the conservation of the existing genetic variability.

Genetichen analiz na populatsii Apis mellifera macedonica (tip �rodopica�) podlozheni na selekcionen kontrol v Bulgariya

The genetic variability in selectively controlled in Bulgaria local honey bee populations, representing Apis mellifera macedonica subspecies (type “rodopica”), has been studied by usage of alloenzymic analysis of six enzymic systems (MDH-1, ME, EST-3, ALP, PGM and HK) corresponding to 6 loci. Totally 324 worker bee individuals from 9 different local populations belonging to breeding stock of National Bee Breeding Association were included in this investigation. All of the studied loci were found to be polymorphic in most of the populations with the exception of EST-3 locus which was established to be fixed in two of investigated populations. Polymorphism with three alleles was ascertained for MDH, ME, ALP and PGM loci and with four alleles – for EST-3 and HK loci. The most common alleles in all of the investigated populations were ME 100, EST-3 100, PGM 100 and HK 100. Two private alleles (frequency < 0.05) were found for two of the studied populations. The calculated level of polymorphism was between 88.33% and 100%. The observed and expected heterozygosities were found to range from 0.186 to 0.301, and from 0.205 to 0.305, respectively. The calculated mean Fst level was 0.028. Allele frequencies of all studied loci were used to estimate Nei’s (1972) genetic distance, which was established to range between 0.001 and 0.028 among the selectively controlled populations studied. The assignment test showed a high level of consolidation for the all studied populations.

Morpho-genetic Analysis of Three River Populations of Bhagna, Labeo ariza (Hamilton 1807) in Bangladesh

Morphological and genetical analysis of Bhagna Labeo ariza H. populations was investigated from three river populations (the Atrai, the Jamuna and the Brahmaputra) of Bangladesh to identify its diversified populations. Therefore, about 30 similar size of fish samples were collected from each of those three river populations and analyzed nine morphometric and meristic characters and their genetic variation by allozyme markers. All of the morphometric characters were significantly higher in (P<0.05) in Atrai population compare to other two river populations. However, among nine meristic characters, five were showed significant differences (P<0.05) among each other. The genetic variations were analyzed with five enzymes (EST, PGM, GPI, LDH and MDH) in CA 6.1 buffer system. Two polymorphic loci Est-1* and Pgm* were interpretable in muscle with starch gel electrophoresis. The highest mean number of allele per locus was observed in the Atrai population (1.375). The mean proportion of heterozygous loci per individual was 4.305% for all populations. The average observed heterozygosity (Ho ) and expected heterozygosity (He) were 0.042 and 0.058, respectively for all the populations. The lowest pair-wise population differentiation (FST) (0.039) and the highest gene flow (Nm) (6.148) were found in the Jamuna–Brahmaputra indicating close relationship among them. In the Nei’s (1972) UPGMA dendrogram, the Jamuna and the Brahmaputra populations of L. ariza made one cluster (D=0.004) and separated from the Atrai population by the genetic distance of 0.066. The results suggest that a considerable genetic variation is existed among the natural L. ariza populations in Bangladesh.

Allozyme polymorphism in mono- and dikaryotic cultures of fungus Schizophyllum commune Fr. (Basidiomycetes)

Allozyme polymorphism of a number of enzyme systems in mono- and dikaryotic cultures of the fungus Schizophyllum commune Fr. isolated from basidiocarps, selected in Ivano-Frankivsk, Chernihiv, and Donetsk regions of Ukraine and Crimea was studied. As a result, 16 alleles of seven gene-enzyme loci were detected. Amy-2, Got, Acp, Sod, and Est-1 loci are considered perspective for use in the population genetic studies of the fungus.

Geographic patterns of Got1, Got2, Got3 and Est2 enzyme-encoding genes allelic variation in Aegilops tauschii Coss.

Geographic patterns of Got1, Got2, Got3 and Est2 enzyme-encoding genes allelic variation were investigated among 322 accessions of Aegilops tauschii Coss., 161 accessions of ssp. tauschii and 161 accessions of ssp. strangulata, representing all the species area. It was found that: (1) in the two ecologically different subspecies, ssp. tauschii and ssp. strangulata, the patterns of allelic variation of the four genes differ greatly; (2) the same allozymes have originated several times independently in different Ae. tauschii local populations; (3) allelic variation of Got1, Got3 and Est2 in ssp. strangulata corresponds to climatic conditions. The data obtained reflected that Ae. tauschii has been inhabiting its area from ancient times; and allelic variation patterns of Got1, Got2, Got3, Est2 loci were mostly formed by natural selection. Further investigations of these loci with molecular genetic methods are prospective for understanding the peculiarities of Ae. tauschii evolution.

Discovery and characterization of novel genetic markers for use in the management of Lahontan cutthroat trout (Oncorhynchus clarkii henshawi)

The Lahontan cutthroat trout (Oncorhynchus clarkii henshawi) is threatened by habitat destruction, over-harvest and hybridization with nonnative trout. Currently, three Geographic Management Units (GMUs) are recognized within the taxon. Here, we describe a suite of 68 single-nucleotide polymorphism (SNP) genetic markers for use in the study and management of Lahontan cutthroat trout and a closely related subspecies, the Paiute cutthroat trout (O. c. seleneris). These include markers variable within the two subspecies (n=35), diagnostic for the two subspecies (n=23) and diagnostic for Yellowstone cutthroat trout (O. c. bouvieri) and other closely related subspecies (n=10). Sixty-three markers were discovered by Sanger sequencing of 171 EST loci in an ascertainment panel including Lahontan cutthroat trout from four populations representing all GMUs. Five markers were identified in a secondary sequencing effort with a single population of Lahontan cutthroat trout. TaqMan assays were validated on six Lahontan cutthroat trout populations and a diverse panel of other trout. Over 90% of the markers variable in Lahontan cutthroat trout were polymorphic in at least two populations, and 66% were variable within all three GMUs. All Lahontan diagnostic markers were also fixed for the Lahontan allele in Paiute cutthroat trout. Most of the Yellowstone diagnostic markers can also be used for this purpose in other cutthroat trout subspecies. This is the first set of SNP markers to be developed for Lahontan cutthroat trout, and will be an important tool for conservation and management.

Paternity Analysis of Tea (Camellia sinensis L. Kuntz) Hybrids Using Isozyme Marker

Tea plant has been categorized as self-incompatible crop. This is the reason behind the high genetic diversity. Natural pollination is possible to occur and the male parent is usually unknown, therefore, there is a need of method to identify male parent of hybrids through paternity analysis. Isozyme markers have been successfully used for paternity analysis due to their co-dominant polymorphism. This research aimed to predict male parents of hybrids by figuring out the mating system through isozyme banding patterns. In this experiment, seven enzyme systems were evaluated, of which only two of the enzyme systems i.e. esterase and shikimate dehydrogenase showing clear band pattern of Est-1, Est-2, and Shd-1 loci. The mating system of tea could be categorized as a mixed mating model, with high estimated out-crossing rate of 98.6 %. The pollen contributors were not always originated from the vicinity of the female parents. Key words: isozyme markers, paternity analysis, tea

The use of esterase polymorphism for analysis of the genetic diversity and structure of stevia (Stevia rebaudiana Bert. Bertoni) populations

Native polyacrylamide gel electrophoresis was used in the current study to identify polymorphisms in α- and β-esterase loci in the leaves of Stevia rebaudiana Bert. Bertoni. The esterases produced from the Est-2 and Est-4 loci were observed as strongly stained bands, and four alleles were detected at each of these loci from the 428 analysed S. rebaudiana plants. The observed and expected mean heterozygosity were higher in populations maintained by genetically breeding plants for higher glycoside production than in plant populations propagated by seeds or maintained by vegetative propagation. The esterase analysis employed in this study showed that the artificial selection of plant samples with specific uniform characteristics, such increased height and precocious flowering, may lead to the fixation of alleles and α/β-esterase phenotype patterns in S. rebaudiana populations. The uniform α/β-esterase phenotype may be applied in the monitoring of genetic stability in selected populations for specific traits of interest.

Genome organization in coffee as revealed by EST PCRRFLP, SNPs and SSR analysis

An EST-based PCR-RFLP method was employed to gain insight into genome organization in eight allopolyploid Coffea arabica cultivars and seven diploid coffee species. The PCR-amplified products at 19 EST loci were digested with 46 different restriction enzymes and size fractioned in agarose gels. Most often, the sum of the fragments length was double or more than the PCR product. In arabica, this condition could be explained by assuming the presence of duplicated loci in paralogous chromosomes and this was supported by considerable evidence of multiple loci SSR amplification. Based on the RFLP analysis, 12 EST loci were polymorphic. The level of polymorphism was higher in different species compared to the arabica varieties. Sequencing of the amplified products revealed a SNP frequency of 0.021 among diploid species and of 0.007 among arabica varieties. We propose that the involvement of two genomes in C. arabica maintains a residual level of heterozygosity in the form of paralogous chromosomes, while the self-fertilization in this species tends to drive of homozygosity. The heterozygosity of paralogous chromosomes in arabica creates valuable polymorphism essential for species diversity and survival in various ecological niches, while self-fertility tends to preserve in homozygosity many genes of functional significance.

Repeated sampling detects gene flow in a flightless ground beetle in a fragmented landscape

Secondary clines level down in the course of time if the gene flow is not interrupted. Temporally repeated sampling of populations in a cline allows the investigation not only of its occurrence but also of the estimation of the amount of ongoing gene flow. We reinvestigated an allozyme gradient in Carabus auronitens populations in the Westphalian Lowlands (northwestern Germany) 15 to 20 years after it had originally been recorded. A total of 977 individuals of this flightless woodland species from 29 sample sites were genotyped at the diallelic Est-1 locus in 2005-2006 and compared to former findings, collected in 1985-1994 from the same populations. Both data sets showed clinal variation. Pairwise differences between the samples of both data sets indicated significant decrease in the steepness of the cline during the past 15 to 20 years. The estimated average gene flow per generation is 0.6% of each beetle population. Ongoing gene flow in the flightless ground beetle C. auronitens led to a less pronounced cline despite a stable degree of fragmentation (and connectivity) of the landscape. Migration and gene flow were obviously enabled by the numerous hedgerows. The corridors are seen to be a prerequisite for migration between populations and for possible future range shifts of forest insect species.

Esterase polymorphisms for analysis of genetic diversity and structure of soybean (Glycine max) cultivars

We used native polyacrylamide gel electrophoresis to identify polymorphism levels in α- and β-esterase loci from leaf tissues of Brazilian soybean cultivars for the analysis of population genetic diversity and structure, and to investigate relationships between conventional and genetically modified cultivars. The cultivars included lines developed by a soybean-grower cooperative (CD), by EMBRAPA (BR), and "Roundup Ready" (RR) cultivars. Esterase isozymes recorded with α-naphthyl acetate and β-naphthyl acetate were produced from 14 loci. Two to three allelic variants were detected in leaves from 420 plants of 21 CD, BR, and RR cultivars at Est-1, Est-2, Est-3, Est-5, and Est-14 loci. The estimated proportion of polymorphic loci in CD cultivars was 21.4%, and in BR and RR cultivars it was 28.6%. High and low H(O) and H(E) values were observed within CD and BR cultivars and a very high cultivar differentiation level was evident in the plants of the 21 CD, BR, and RR cultivars (F(ST) = 0.3865). A low level of differentiation (F(ST) = 0.0289) was detected between conventional and RR cultivars. Plants from cultivar BR37 had the highest level of genetic differentiation compared to the other cultivars. The genetic basis of BR cultivars (0.5538-0.9748) was found to be broader than the genetic basis of CD cultivars (0.7058 for CD205 and CD209 and 0.9995 for CD205 and CD208). Higher genetic identity was detected between plants of CD and CDRR cultivars (I = 0.9816). Understanding the genetic structure of these populations can help provide specific culture strategies for each cultivar, depending on its level of heterozygosity.

Molecular markers assist in the development of diverse inbred backcross lines in European Long cucumber (Cucumis sativus L.)

The popular fresh-market European Long cucumber (Cucumis sativus L.) is grown commercially worldwide under controlled, greenhouse environments. However, it has a narrow genetic base, where private and public improvement programs can trace their origins to comparatively few accessions. Therefore, a project was designed to identify diverse genotypes for use in the formation and analysis of inbred backcross (BC2S3) lines (IBL) to broaden the genetic base of this market class. Initially, 42 cucumber accessions were evaluated with a previously defined standard marker array to identify parents for use in backcrossing. The IBL were developed by crossing the elite commercial line NZ1 (Nunhems Vegetable Seeds, Haelen, The Netherlands) and PI 432858 (China), and then backcrossing the most genetically diverse BC1 and BC2 progeny to the elite parent as defined by marker analyses (19 polymorphic, mapped SSR, and SCAR marker loci), followed by three generations of single seed descent resulting in 116 IBL (BC2S3). The IBL were evaluated under greenhouse conditions for days to anthesis, sex expression, lateral branch number, yield, and exterior fruit quality in Madison, Wisconsin, USA (soil media), and in Haelen and Bergschenhoek, The Netherlands (soilless, hydroponic media). The IBL were genotyped using an expanded marker array (37 polymorphic SSR, SCAR, SNP, EST, BAC end, and gene-associated loci), and genetic relationships were examined by multivariate analyses using phenotypic and genotypic data. The 116 developed IBL possessed considerable morphological and genotypic diversity, where genetic distance (GD) among lines ranged between 0.00 and 0.77. These IBL possessed many commercially acceptable attributes, and, thus, genetic diversity in this market type could be substantially increased by the use of these genetically broad-based IBL during plant improvement.

Variation at the Est3 locus and adaptability to organophosphorous compounds in Zaprionus indianus populations

AbstractCarboxylesterases are enzymes often associated with insect resistance to insecticides. The Est3 locus of Zaprionus indianus Gupta (Diptera: Drosophilidae) harbors four alleles that encode carboxylesterases with potentially detoxifying roles. In this study, we propose a model of resistance to insecticides in Z. indianus based on the adaptability of the Est3 locus inferred from the spread of its alleles over 27 generations in experimental populations, and their frequencies in field populations, which were either exposed or unexposed to the organophosphorous insecticide malathion. The increase in the frequency of this allele in experimental populations, and its high prevalence in field populations exposed to organophosphorous insecticides suggest that natural selection favors individuals with the Est3‐3 allele. The low frequency of this allele in unexposed field populations, and the low productivity of Est3‐3 homozygotes indicate that an adaptive cost is associated with this allele. The existence of a marker locus for insecticide resistance in Z. indianus makes it possible to use this species as a bioindicator for monitoring the excessive use of organophosphorous products and the emergence of resistance, and to devise strategies for the management of agricultural pests.