BUSINESS REPUTATION SYSTEMS BASED ON BLOCKCHAIN TECHNOLOGY—A RISKY ADVANCE

Reputation is indispensable for online business since it supports customers in their buying decisions and allows sellers to justify premium prices. While IS research has investigated reputation systems mainly as review systems on online platforms for business-to-consumer (B2C) transactions, no proper solutions have been developed for business-to-business (B2B) transactions yet. We use blockchain technology to propose a new class of reputation systems that apply ratings as voluntary bonus payments: Before a transaction is performed, customers commit to pay a bonus that is granted if a service provider has performed a service properly. As opposed to rival reputation systems that build on cumulated ratings or reviews, our system enables monetized reputation mechanisms that are inextricably linked with online transactions. We expect this system class to provide more trustworthy ratings, which might reduce agency costs and serve quality providers to establish a reputation towards new customers, building on second-order trust

Business Reputation Systems Based on Blockchain Technology - A Risky Advance

Reputation is indispensable for online business since it supports customers in their buying decisions and allows sellers to justify premium prices. While IS research has investigated reputation systems mainly as review systems on online platforms for business-to-consumer (B2C) transactions, no proper solutions have been developed for business-to-business (B2B) transactions yet. We use blockchain technology to propose a new class of reputation systems that apply ratings as voluntary bonus payments: Before a transaction is performed, customers commit to pay a bonus that is granted if a service provider has performed a service properly. As opposed to rival reputation systems that build on cumulated ratings or reviews, our system enables monetized reputation mechanisms that are inextricably linked with online transactions. We expect this system class to provide more trustworthy ratings, which might reduce agency costs and serve quality providers to establish a reputation towards new customers

Data from: Quantifying realized inbreeding in wild and captive animal populations

Most molecular measures of inbreeding do not measure inbreeding at the scale that is most relevant for understanding inbreeding depression—namely the proportion of the genome that is identical-by-descent (IBD). The inbreeding coefficient FPed obtained from pedigrees is a valuable estimator of IBD, but pedigrees are not always available, and cannot capture inbreeding loops that reach back in time further than the pedigree. We here propose a molecular approach to quantify the realized proportion of the genome that is IBD (propIBD), and we apply this method to a wild and a captive population of zebra finches (Taeniopygia guttata). In each of 948 wild and 1057 captive individuals we analyzed available single-nucleotide polymorphism (SNP) data (260 SNPs) spread over four different genomic regions in each population. This allowed us to determine whether any of these four regions was completely homozygous within an individual, which indicates IBD with high confidence. In the highly nomadic wild population, we did not find a single case of IBD, implying that inbreeding must be extremely rare (propIBD=0–0.00094, 95% CI). In the captive population, a five-generation pedigree strongly underestimated the average amount of realized inbreeding (FPed=0.013<propIBD=0.064), as expected given that pedigree founders were already related. We suggest that this SNP-based technique is generally useful for quantifying inbreeding at the individual or population level, and we show analytically that it can capture inbreeding loops that reach back up to a few hundred generations

Fitness consequences of polymorphic inversions in the zebra finch genome

Background: Inversion polymorphisms constitute an evolutionary puzzle: they should increase embryo mortality in heterokaryotypic individuals but still they are widespread in some taxa. Some insect species have evolved mechanisms to reduce the cost of embryo mortality but humans have not. In birds, a detailed analysis is missing although intraspecific inversion polymorphisms are regarded as common. In Australian zebra finches (Taeniopygia guttata), two polymorphic inversions are known cytogenetically and we set out to detect these two and potentially additional inversions using genomic tools and study their effects on embryo mortality and other fitness-related and morphological traits. Results: Using whole-genome SNP data, we screened 948 wild zebra finches for polymorphic inversions and describe four large (12-63 Mb) intraspecific inversion polymorphisms with allele frequencies close to 50%. Using additional data from 5229 birds and 9764 eggs from wild and three captive zebra finch populations, we show that only the largest inversions increase embryo mortality in heterokaryotypic males, with surprisingly small effect sizes. We test for a heterozygote advantage on other fitness components but find no evidence for heterosis for any of the inversions. Yet, we find strong additive effects on several morphological traits. Conclusions: The mechanism that has carried the derived inversion haplotypes to such high allele frequencies remains elusive. It appears that selection has effectively minimized the costs associated with inversions in zebra finches. The highly skewed distribution of recombination events towards the chromosome ends in zebra finches and other estrildid species may function to minimize crossovers in the inverted regions.22 page(s

data.genotypes

The file contains the genotypes of all 948 individuals studied. Each row represents one individual.The first column gives the individual ID followed by the genotypes of all SNPs. Alleles are coded as 0, 1 or 2 representing 0, 1 or 2 copies of the A-Allele, respectively

Data from: Association mapping of morphological traits in wild and captive zebra finches: reliable within but not between populations

Identifying causal genetic variants underlying heritable phenotypic variation is a longstanding goal in evolutionary genetics. We previously identified several quantitative trait loci (QTL) for five morphological traits in a captive population of zebra finches (Taeniopygia guttata) by whole-genome linkage mapping. We here follow up on these studies with the aim to narrow down on the quantitative trait variants (QTN) in one wild and three captive populations. First, we performed an association study using 672 single nucleotide polymorphisms (SNPs) within candidate genes located in the previously identified QTL regions in a sample of 939 wild-caught zebra finches. Then, we validated the most promising SNP-phenotype associations (n = 25 SNPs) in 5,228 birds from four populations. Genotype-phenotype associations were generally weak in the wild population, where linkage disequilibrium (LD) spans only short genomic distances. In contrast, in captive populations, where LD blocks are large, apparent SNP-effects on morphological traits (i.e. associations) were highly repeatable with independent data from the same population. Most of those SNPs also showed significant associations with the same trait in other captive populations, but the direction and magnitude of these effects varied among populations. This suggests that the tested SNPs are not the causal QTN but rather physically linked to them, and that LD between SNPs and causal variants differs between populations due to founder effects. While the identification of QTN remains challenging in non-model organisms, we illustrate that it is indeed possible to confirm the location and magnitude of QTL in a population with stable linkage between markers and causal variants

data.genes

The file contains all SNP names and their location within a gene

Association mapping of morphological traits in wild and captive zebra finches : reliable within, but not between populations

Identifying causal genetic variants underlying heritable phenotypic variation is a long-standing goal in evolutionary genetics. We previously identified several quantitative trait loci (QTL) for five morphological traits in a captive population of zebra finches (Taeniopygia guttata) by whole-genome linkage mapping. We here follow up on these studies with the aim to narrow down on the quantitative trait variants (QTN) in one wild and three captive populations. First, we performed an association study using 672 single nucleotide polymorphisms (SNPs) within candidate genes located in the previously identified QTL regions in a sample of 939 wild-caught zebra finches. Then, we validated the most promising SNP–phenotype associations (n = 25 SNPs) in 5228 birds from four populations. Genotype–phenotype associations were generally weak in the wild population, where linkage disequilibrium (LD) spans only short genomic distances. In contrast, in captive populations, where LD blocks are large, apparent SNP effects on morphological traits (i.e. associations) were highly repeatable with independent data from the same population. Most of those SNPs also showed significant associations with the same trait in other captive populations, but the direction and magnitude of these effects varied among populations. This suggests that the tested SNPs are not the causal QTN but rather physically linked to them, and that LD between SNPs and causal variants differs between populations due to founder effects. While the identification of QTN remains challenging in nonmodel organisms, we illustrate that it is indeed possible to confirm the location and magnitude of QTL in a population with stable linkage between markers and causal variants.21 page(s

Additional file 1: Figure S1. of Fitness consequences of polymorphic inversions in the zebra finch genome

Linkage disequilibrium and principal component analysis results along chromosomes Tgu2, Tgu26 and Tgu27. Figure S2. Composite LD between eigenvectors of PC1 to PC3 and the SNPs along chromosome Tgu5. Figure S3. Composite LD between eigenvectors of PC1 to PC3 and the SNPs along chromosome Tgu11. Figure S4. Composite LD between eigenvectors of PC1 to PC4 and the SNPs along chromosome Tgu13. Figure S5. Composite LD between eigenvectors of PC1 to PC5 and the SNPs along chromosome TguZ. Figure S6. Median-joining networks of phased SNPs for the inversions on chromosomes Tgu5, Tgu11, Tgu13 and TguZ. Figure S7. Diversity in 50 kb windows along each chromosome in the zebra finch genome. Figure S8. Dominance effects of mother’s and father’s inversion karyotype on embryo mortality in three captive populations. Figure S9. Additive effects of the minor inversion allele on different fitness parameters in three captive populations. Figure S10. Negative frequencydependent selection effects on different fitness parameters in two captive populations. Figure S11. Dominance effects of the minor inversion allele on morphological phenotypes in three captive and two wild populations. Figure S12. Composite LD along chromosome TguZ between all combinations of the three inversion haplotypes. Figure S13. Linkage disequilibrium and principal component analysis results along chromosomes Tgu5, Tgu11, Tgu13 and TguZ using a filtered SNP set. Figure S14. Principle component analysis results from the wild “Fowlers Gap” birds along chromosome Tgu5, Tgu11, Tgu13 and TguZ together with the founders of the three captive populations. Color coded are the inversion type calls for each individual using only the information from the tag SNPs as described in the Methodssection. Figure S15. Principle component analysis results from the wild “Fowlers Gap” birds along chromosome Tgu5, Tgu11, Tgu13 and TguZ with PCA scores of founder individuals of the three captive populations overlaid. (DOCX 8865 kb