Founder Generation Research Articles

Conservation of placentation during the tertiary radiation of mammals in South America

The eutherian placenta is considered to possess great plasticity, but it is not clear how this variation reflects adaptation to different ecological niches. Because South America was isolated for most of the Tertiary, it represents a natural laboratory to examine this question. We here describe placentation in three South American groups: Xenarthra have been part of the fauna from at least the mid-Paleocene whereas caviomorph rodents and Neotropical primates are each derived from a single founder that reached South America in the Eocene and Oligocene, respectively. The common ancestor of Xenarthra had a villous, haemochorial placenta, from which the labyrinthine, endotheliochorial placenta of sloths later evolved. Placentation in Caviomorpha follows an extraordinary stable pattern, characterized by a haemomonochorial, labyrinthine and highly lobed structure with specialized growing areas. This pattern was present before arrival of these rodents in South America and enabled a successful radiation especially during the spread of grasslands. Neotropical primates have haemochorial, trabecular placentas with a specialized maternal blood supply; a pattern that contrasts with that of Old World monkeys and may have been present in the founder generation on arrival in South America. In conclusion, there is a dichotomy within Xenarthra but otherwise the ancient South American mammals do not show much variation in principal placental characters. Thus, the successful radiation of these three groups, and their adaptation to diverse ecological niches, did not require substantial alterations in placentation.

Non-family employees in small family business succession: the case of psychological ownership

This study is analysing non-family employees' perceptions on psychological ownership during the family business succession process. Three small family companies were chosen for the multiple case studies. The results of this study show that non-family employees are participating on the small family business succession and they do possess a strong psychological ownership towards the family business, their own work, and the founder generation. Non-family employees recognise the changing management and leadership in successions. Non-family employees' psychological ownership increases in succession. This has got influence on commitment and well being in unique way according to personal characteristics of a non-family employee.

Expression Systems and Species Used for Transgenic Animal Bioreactors

Transgenic animal bioreactors can produce therapeutic proteins with high value for pharmaceutical use. In this paper, we compared different systems capable of producing therapeutic proteins (bacteria, mammalian cells, transgenic plants, and transgenic animals) and found that transgenic animals were potentially ideal bioreactors for the synthesis of pharmaceutical protein complexes. Compared with other transgenic animal expression systems (egg white, blood, urine, seminal plasma, and silkworm cocoon), the mammary glands of transgenic animals have enormous potential. Compared with other mammalian species (pig, goat, sheep, and cow) that are currently being studied as bioreactors, rabbits offer many advantages: high fertility, easy generation of transgenic founders and offspring, insensitivity to prion diseases, relatively high milk production, and no transmission of severe diseases to humans. Noticeably, for a small- or medium-sized facility, the rabbit system is ideal to produce up to 50 kg of protein per year, considering both economical and hygienic aspects; rabbits are attractive candidates for the mammary-gland-specific expression of recombinant proteins. We also reviewed recombinant proteins that have been produced by targeted expression in the mammary glands of rabbits and discussed the limitations of transgenic animal bioreactors.

Transposon‐mediated transgenesis, transgenic rescue, and tissue‐specific gene expression in rodents and rabbits

Germline transgenesis is an important procedure for functional investigation of biological pathways, as well as for animal biotechnology. We have established a simple, nonviral protocol in three important biomedical model organisms frequently used in physiological studies. The protocol is based on the hyperactive Sleeping Beauty transposon system, SB100X, which reproducibly promoted generation of transgenic founders at frequencies of 50-64, 14-72, and 15% in mice, rats, and rabbits, respectively. The SB100X-mediated transgene integrations are less prone to genetic mosaicism and gene silencing as compared to either the classical pronuclear injection or to lentivirus-mediated transgenesis. The method was successfully applied to a variety of transgenes and animal models, and can be used to generate founders with single-copy integrations. The transposon vector also allows the generation of transgenic lines with tissue-specific expression patterns specified by promoter elements of choice, exemplified by a rat reporter strain useful for tracking serotonergic neurons. As a proof of principle, we rescued an inborn genetic defect in the fawn-hooded hypertensive rat by SB100X transgenesis. A side-by-side comparison of the SB100X- and piggyBac-based protocols revealed that the two systems are complementary, offering new opportunities in genome manipulation.

Inferring haplotypes and parental genotypes in larger full sib-ships and other pedigrees with missing or erroneous genotype data.

BackgroundIn many contexts, pedigrees for individuals are known even though not all individuals have been fully genotyped. In one extreme case, the genotypes for a set of full siblings are known, with no knowledge of parental genotypes. We propose a method for inferring phased haplotypes and genotypes for all individuals, even those with missing data, in such pedigrees, allowing a multitude of classic and recent methods for linkage and genome analysis to be used more efficiently.ResultsBy artificially removing the founder generation genotype data from a well-studied simulated dataset, the quality of reconstructed genotypes in that generation can be verified. For the full structure of repeated matings with 15 offspring per mating, 10 dams per sire, 99.89% of all founder markers were phased correctly, given only the unphased genotypes for offspring. The accuracy was reduced only slightly, to 99.51%, when introducing a 2% error rate in offspring genotypes. When reduced to only 5 full-sib offspring in a single sire-dam mating, the corresponding percentage is 92.62%, which compares favorably with 89.28% from the leading Merlin package. Furthermore, Merlin is unable to handle more than approximately 10 sibs, as the number of states tracked rises exponentially with family size, while our approach has no such limit and handles 150 half-sibs with ease in our experiments.ConclusionsOur method is able to reconstruct genotypes for parents when genotype data is only available for offspring individuals, as well as haplotypes for all individuals. Compared to the Merlin package, we can handle larger pedigrees and produce superior results, mainly due to the fact that Merlin uses the Viterbi algorithm on the state space to infer the genotype sequence. Tracking of haplotype and allele origin can be used in any application where the marker set does not directly influence genotype variation influencing traits. Inference of genotypes can also reduce the effects of genotyping errors and missing data. The cnF2freq codebase implementing our approach is available under a BSD-style license.

Evolutionary selection and variation in family businesses

PurposeThis qualitative study attempts to understand what kinds of evolutionary selection and variation occur in family businesses during the preparation of a managerial and ownership succession.Design/methodology/approachThe study was conducted by interviewing members of one family business in Louisiana, USA and one in Finland in order to contribute to the understanding of succession preparation in small family businesses with two generations. Evolutionary economics was adapted for this interdisciplinary study to explain evolutionary changes in a family business succession.FindingsThe findings indicate that both selection and variation can take place through different routes during the preparatory phase of a family business succession. Selection is influenced both by the founder and next generations. However, it does not occur in company A due to the reluctance of the younger generation. In company B selection is processed through joint thinking and visioning. This will lead to variation which is shaped by both generations.Research limitations/implicationsThis study is based on qualitative interpretation. Limitations of the study are the small number of informants and the lack of generalization of the results.Practical implicationsThis study shows that selection and variation are intertwined. If selection does not occur in a family business, it leads to no variation between the generations. However, exits are possible; death and birth of companies are part of the life cycle of family businesses.Originality/valueEvolutionary thinking has not been studied recently among family firms except in the field of evolutionary psychology. Evolutionary thinking offers a variety of topics to study in the future.

Haplotype inference based on Hidden Markov Models in the QTL-MAS 2010 multi-generational dataset

BackgroundWe have previously demonstrated an approach for efficient computation of genotype probabilities, and more generally probabilities of allele inheritance in inbred as well as outbred populations. That work also included an extension for haplotype inference, or phasing, using Hidden Markov Models. Computational phasing of multi-thousand marker datasets has not become common as of yet. In this communication, we further investigate the method presented earlier for such problems, in a multi-generational dataset simulated for QTL detection.ResultsWhen analyzing the dataset simulated for the 14th QTLMAS workshop, the phasing produced showed zero deviations compared to original simulated phase in the founder generation. In total, 99.93% of all markers were correctly phased. 97.68% of the individuals were correct in all markers over all 5 simulated chromosomes. Results were produced over a weekend on a small computational cluster. The specific algorithmic adaptations needed for the Markov model training approach in order to reach convergence are described.ConclusionsOur method provides efficient, near-perfect haplotype inference allowing the determination of completely phased genomes in dense pedigrees. These developments are of special value for applications where marker alleles are not corresponding directly to QTL alleles, thus necessitating tracking of allele origin, and in complex multi-generational crosses. The cnF2freq codebase, which is in a current state of active development, is available under a BSD-style license.

Strategies for selection marker-free swine transgenesis using the Sleeping Beauty transposon system

Swine transgenesis by pronuclear injection or cloning has traditionally relied on illegitimate recombination of DNA into the pig genome. This often results in animals containing concatemeric arrays of transgenes that complicate characterization and can impair long-term transgene stability and expression. This is inconsistent with regulatory guidance for transgenic livestock, which also discourages the use of selection markers, particularly antibiotic resistance genes. We demonstrate that the Sleeping Beauty (SB) transposon system effectively delivers monomeric, multi-copy transgenes to the pig embryo genome by pronuclear injection without markers, as well as to donor cells for founder generation by cloning. Here we show that our method of transposon-mediated transgenesis yielded 38 cloned founder pigs that altogether harbored 100 integrants for five distinct transposons encoding either human APOBEC3G or YFP-Cre. Two strategies were employed to facilitate elimination of antibiotic genes from transgenic pigs, one based on Cre-recombinase and the other by segregation of independently transposed transgenes upon breeding.

In search of family business continuity: the case of transgenerational family entrepreneurship

This qualitative case study analyses continuity of transgenerational entrepreneurship in the family business. Transgenerational entrepreneurship is based on multigenerational, and in this particular firm, on the founder and next generation, business activities in the same family business. Methodologically, the data was collected by interviewing members of two generations of Imagon Ltd.; the founder, and his sons. Imagon Ltd. shows signs of transgenerational continuity. It did not start off that way in the founder’s mind; his desire was just to work for himself and fulfil his own visions. It was only much later that the prospect of defining his company as a family business entered the picture during which time the succession process started naturally. The potential constraint for transgenerational value creation is the possible loss of next generation interest and therefore having no one to take over at that time.

Refined candidate region specified by haplotype sharing for Escherichia coli F4ab/F4ac susceptibility alleles in pigs

Infection of the small intestine by enterotoxigenic Escherichia coli F4ab/ac is a major welfare problem and financial burden for the pig industry. Natural resistance to this infection is inherited as a Mendelian recessive trait, and a polymorphism in the MUC4 gene segregating for susceptibility/resistance is presently used in a selection programme by the Danish pig breeding industry. To elucidate the genetic background involved in E. coli F4ab/ac susceptibility in pigs, a detailed haplotype map of the porcine candidate region was established. This region covers approximately 3.7 Mb. The material used for the study is a three generation family, where the founders are two Wild boars and eight Large White sows. All pigs have been phenotyped for susceptibility to F4ab/ac using an adhesion assay. Their haplotypes are known from segregation analysis using flanking markers. By a targeted approach, the candidate region was subjected to screening for polymorphisms, mainly focusing on intronic sequences. A total of 18 genes were partially sequenced, and polymorphisms were identified in GP5, CENTB2, APOD, PCYT1A, OSTalpha, ZDHHC19, TFRC, ACK1, MUC4, MUC20, KIAA0226, LRCH3 and MUC13. Overall, 227 polymorphisms were discovered in the founder generation. The analysis revealed a large haplotype block, spanning at least 1.5 Mb around MUC4, to be associated with F4ab/ac susceptibility.

Small family business performance: comparison between family and non-family enterprises

This study compares small family business performance between the Finnish family and non-family enterprises. The sample (2,004 firms) was derived to represent nationally small businesses, in collaboration with the Statistics Finland (Centre) in Helsinki. The answer rate of the study was 90% (data collected by mail questionnaires and telephone interviews). The method of the study was to compare family and non-family enterprises with ROA (return on assets) on an enterprise population level (Finland). The results of the study show that most of the small family businesses are controlled by the founder generation. Founder generation performance was slightly higher than among descendant generation controlled firms. Family businesses were more profitable than non-family businesses in the sector of small enterprises.

Zinc finger nuclease technology heralds a new era in mammalian transgenesis

Non-mouse mammalian transgenesis is limited by its overall inefficiency and technical hurdles. Recent years have seen the emergence of two approaches that are applicable to most mammals. The first, based on lentivirus vectors, allows efficient generation of transgenic founders, most of them expressing the transgene. The second, recently applied to produce transgenic fish and mammals, takes advantage of the design of specific 'DNA-scissors' for efficient introduction of subtle mutations in potentially any region of the genome. This review focuses on the potential of this latter technology to modify mammalian genomes without the need to apply challenging and less-efficient protocols. We highlight the complementary aims of these new approaches and the as-yet-unexplored possibilities offered by their combination.

Litter size, infant mortality and female body weight in captive black-and-white ruffed lemurs Varecia variegata

We describe the development of selected life history traits (infant mortality, litter size) in a captive primate population and assess the role of resource abundance in observed changes in these traits. We studied patterns in the long-term development of litter size and infant mortality in the world captive population of Varecia variegata comprising 2186 ind. registered in the International Studbook and in the European Regional Studbook over a period of 40 yr. We also collected body weight data from 98 ruffed lemurs in 14 European zoos. Infant mortality increased significantly over the study period and from the founder to the F1 generation, with a mean litter size of 1.78 in the wild- born founder generation, compared to 2.14 for the zoo-born generations combined. A litter size of 4 had the highest rate of survival per litter. Female body weight, which we found to increase over the generations, had a significant positive correlation with litter size, but did not correlate with infant mortality. We suggest that changes in life history traits of a captive primate population, such as those in infant mortality and litter size of V. variegata, may be due to altered living conditions in captivity and that these changes may ultimately lead to a loss of genetic variability. High female body weight in captivity may indirectly contribute to changes in the demographic structure of a population. Our results suggest that management tools to control such developments need to be established for use in coordinated breeding programmes for endangered species.

La filosofía en México en el siglo XX: un breve informe

The author presents a report, writing in the 90's and unpublished in Spanish, which could be of use for the current discussion on Mexican philosophy. In this report, Pereda divides the history of Mexican philosophy in 4 phases: "the generation of founders", the "transterrados" or exiled, "the epoch of great blocks", and the "irruption of archipelago".

FAMILY BUSINESS SUCCESSION: EVOLUTIONARY ECONOMICS APPROACH

This study analyses family business continuity from founder generation to the 2nd generation in terms of succession in the context of evolutionary economics. Two literature bases; family business succession and evolutionary thinking in organisational and economic change, are reviewed and combined to provide insights to understand the nature of family business succession. Operation of the key evolutionary forces — variation, selection, retention and struggle — in family business succession are illustrated. Regarding variation, there is a concern for understanding the importance of having enough diversity within the family firm, since this diversity of routines and competences comprises the pool of variation from which to select when the environment changes. With regards to selection, there is a concern for understanding the risk of selection bias easily rooted in the family firm culture: are some variations favoured in the selection of operating, investment and search routines because of family relations, emotions and values, including decisions on who will succeed and who will own the firm in the future. Elaboration and investigation of these concepts may help to identify special characteristics of the "family firm species" that are either beneficial or risky for the survival in the evolutionary struggle.

The first Pálffy Portrait Gallery in Červený Kameň Castle (Vöröskő, Bibersburg)

Summary In Slovakia the rest of the Palffy collection is preserved in some institutions (Cervený Kameň, Slovak National Museum, Bratislava; Slovak National Gallery, Bratislava; Bojnice Castle). The oldest family collections – also including art relics of the first generation – are guarded in Cervený Kameň Castle. The building and art patronage activities of the first generation of founders (1538–1619) Nicolas II. Palffy and his wife Maria Madeleine Fugger ought to be reconstructed on the basis of archival and literary sources to show their real scale and significance. The first Palffy portrait gallery was aimed at representing the high rank of the family, and was situated probably both in the long hall and staircase of “piano nobile” in the residence. It seems there were several portraits of Maria Madeleine (as a fiancee and also as a richly dressed countess), surely some portraits of Count Nicolas (known as a significant military hero and several times portrayed for graphical series of “famous men”) and ...

Potential of the Quantitative Trait Loci Mapping Using Crossbred Population

In the process of crossbreeding, the linkage disequilibria between the quantitative trait loci (QTL) and their linked markers were reduced gradually with increasing generations. To study the potential of QTL mapping using the crossbred population, we presented a mixed effect model that treated the mean allelic value of the different founder populations as the fixed effect and the allelic deviation from the population mean as random effect. It was assumed that there were fifty QTLs having effect on the trait variation, the population mean and variance were divided to each QTL in founder generation in our model. Only the additive effect was considered in this model for simulation. Six schemes (S1-S6) of crossbreeding were studied. The selection index was used to evaluate the synthetic breeding value of two traits of the individual in the scheme of S2, S4 and S6, and the individuals with high selection index were chosen as the parents of the next generation. Random selection was used in the scheme of S1, S3 and S5. In this study, we premised a QTL explained 40% of the genetic variance was located in a region of 20 cM by the linkage analysis previously. The log likelihood ratio (log LR) was calculated to determine the presence of a QTL at the particular chromosomal position in each of the generations from the fourth to twentieth. The profiles of log LR and the number of the highest log LR located in the region of 5, 10 and 20 cM were compared between different generations and schemes. The profiles and the correct number reduced gradually with the generations increasing in the schemes of S2, S4 and S6, but both of them increased in the schemes of S1, S3 and S5. From the results, we concluded that the crossbreeding population undergoing random selection was suitable for improving the resolution of QTL mapping. Even experiencing index selection, there was still enough variation existing within the crossbred population before the fourteenth generation that could be used to refine the location of QTL in the chromosome region.

Genetic management of the red squirrel, Sciurus vulgaris: a practical approach to regional conservation

The progressive decline in red squirrel (Sciurus vulgaris) numbers in Wales has led to conservation and reintroduction projects being established on the island of Anglesey. The recovery of the island’s remnant wild population was initially successful, however concern remained over potential loss of genetic diversity resulting from an observed demographic bottleneck. We used mitochondrial DNA (mtDNA) control region sequences and six microsatellite loci to assess current levels of genetic variation in the population. Samples were monomorphic for control region sequences and a historic specimen from the same area carrying a different haplotype demonstrated a loss of mtDNA diversity during the last 20 years. Inclusion of other Welsh haplotypes indicated phylogeographic structure in the region, in contrast to previous UK studies. Genotyping results showed allelic diversity and heterozygosity to be less than 50% of that recorded in other UK populations, with strong evidence for a recent genetic bottleneck. A parallel reintroduction programme on Anglesey included genetic analysis of individuals during the selection of captive breeding pairs. We present analysis of sequence and microsatellite data, and subsequent management decisions taken to maximise diversity in the founder and F1 generations. Population and Habitat Viability Analysis applied to both populations modelled future levels of heterozygosity and allelic diversity. Supplementation of the remnant and reintroduced populations with translocated squirrels was simulated as a potential management tool; results support use of this strategy to reduce loss of diversity and increase survival. The limitations of applying conservation genetic theory within small-scale management projects are discussed.

Les applications de la transgenèse animale

Transgenesis is the introduction of a new gene in a whole organism to generate animal lines harbouring new genetic traits or having lost a gene. This procedure helps our understanding of the mechanisms regulating gene expression as well as the function of genes in the body. Transgenesis provides models to study human diseases and prepares animals as potential sources of organs and cells, as well as pharmaceutical proteins, to be used in man. Transgenesis creates genetically modified farm animals, thereby increasing and targeting biodiversity. However, the success of animal transgenesis is still restricted by several problems, particularly technical and financial. Gene transfer remains difficult in large animals even if new techniques have brought decisive improvements. Another problem is the often poorly controlled expression of transgenes. This requires the generation of multiple founders to keep only the best, and reduce the unpredictable side effects of transgenesis. The applications of transgenesis in farm animals are also limited by the availability of genes expected to bring a significant improvement over pre-existing lines. Animal transgenesis must also deal with issues of biosafety and acceptability by consumers. This article reviews the major advances in animal transgenesis.

Impact of founder population, drift and selection on the genetic diversity of a recently translocated tree population.

Recently established, temperate tree populations combine a high level of differentiation for adaptive traits, suggesting rapid genetic evolution, with a high level of genetic diversity within population, suggesting a limited impact of genetic drift and purifying selection. To study experimentally the evolutionary forces in a recently established population, we assessed the spatial and temporal patterns of genetic diversity within a disjunct population of Cedrus atlantica established 140 years ago in south-eastern France from a North African source. The population is expanding through natural regeneration. Three generations were sampled, including founder trees. We analysed 12 isozyme loci, three of which were previously found in tight association with selected genes, and quantitative traits. No bottleneck effect was detected in the founder generation, but a simple test of allelic association revealed an initial disequilibrium which disappeared in the following generations. The impact of genetic drift during secondary evolution was limited, as suggested by the weak temporal differentiation. The genetic load was not reduced after 3 generations, and the quantitative variation for adaptive traits did not change either. Thus, initial genetic changes first proceed from a rapid re-organisation of the diversity through mating and recombination, whereas genetic erosion through drift and selection is delayed due to temporal and spatial stochasticity. Two life-history traits of trees contribute to slowing down the processes of genetic erosion: perenniality and large spatial scale. Thus, one would expect recently established tree populations to have a higher diversity than older ones, which seems in accordance with experimental surveys.