In situ hybridization (multicolor GISH and FISH) was used to characterize the genomic composition of the wheat-Thinopyrum ponticum partial amphiploid BE-1. The amphiploid is a high-protein line having resistance to leaf rust (Puccinia recondita f. sp. tritici) and powdery mildew (Blumeria graminis f. sp. tritici) and has in total 56 chromosomes per cell. Multicolor GISH using J, A and D genomic probes showed 16 chromosomes originating from Thinopyrum ponticum and 14 A genome, 14 B genome and 12 D genome chromosomes. Six of the Th. ponticum chromosomes carried segments different from the J genome in their centromeric regions. It was demonstrated that these alien chromosome segments did not originate from the A, B or D genomes of wheat, so the translocation chromosomes were considered to be J(s) type chromosomes carrying segments similar to the S genome near the centromeres. Rearrangements between the A and D genomes of wheat were detected. FISH using Afa family, pSc119.2 and pTa71 probes allowed the identification of all the wheat chromosomes present and the determination of the chromosomes involved in the translocations. The 4A and 7A chromosomes were identified as being involved in intergenomic translocations. The replaced wheat chromosome was identified as 7D. The localization of these repetitive DNA clones on the Th. ponticum chromosomes of the amphiploid was described in the present study. On the basis of their multicolor FISH patterns, the alien chromosomes could be arranged in eight pairs and could also be differentiated unequivocally from each other.
I study a principal-agent model in which the agent collects information and then chooses a verifiable action. I show that the principal can find it desirable to constrain the agent's action set even though there is no disagreement about the ranking of actions "ex post". The elimination or penalization of "intermediate" actions, which are optimal when information is poor, improves incentives for information collection. I characterize optimal action sets when the agent is infinitely risk averse with respect to income shocks and optimal incentive schemes when the agent is risk neutral. Copyright The Review of Economic Studies Limited, 2005.
This paper studies the impact of …nancing constraints on the equilibrium of a patent race. We develop a model where …rms …nance their R&D expenditures with an investor who cannot verify their e¤ort. We solve for the optimal …nancial contract of any …rm along its best-response function. In equilibrium, any …rm in the race is more likely to win the more cash and assets it holds prior to the race, and the less cash and assets its rivals hold prior to the race. We use NBER evidence from pharmaceutical patents awarded between 1975 and 1999 in the US, patent citations, and COMPUSTAT to measure the e¤ect of all the racing …rms' cash holdings on the equilibrium winning probabilities. The empirical …ndings support our theoretical predictions.Keywords: Patent Race, optimal contract, innovation, …nancial constraints. JEL Classi…cation: G24, G32, L13 1 Do a …rm's …nancing constraints a¤ect its decisions to pursue innovation? Since Fazzari, Hubbard, and Petersen's (1988) seminal paper, economists have found that …nancing matters through various channels for total …rm level investment in R&D. For example, Hall (1992) shows that the source of …nancing matters and Himmelberg and Petersen (1994) show that internal …nance predicts R&D expenditures of small high tech …rms. But do a …rm's …nancing constraints also a¤ect its rivals'decisions to pursue innovations?To our surprise, the role of …nancing constraints in patent races hasn't been comprehensively studied in the literature. Theorists have focused mainly on how …rms' R&D e¤ort depends on technological standing and market structure.1 In this paper, we incorporate …-nancing constraints explicitly into Reinganum's (1983) seminal model and test the model's comparative statics predictions empirically. In our model, …rms …nance their R&D expenditures with internal and external funds. The probability of making the discovery at a point in time depends on the e¤ort exerted by the entrepreneur, which cannot be veri…ed by the investor. In equilibrium, …nance is costly for the entrepreneur and the marginal cost of innovative activity is increasing in the fraction of outside funds to the total investment, very much following the logic proposed by Jensen and Meckling (1976). An increase in the marginal cost of innovating shifts a …rm's best response function downwards which in turn decreases the …rm's equilibrium R&D expenditures. The practical upshot is that in a setting of strategic interactions, deep pockets are a source of comparative advantage. This prediction is testable and is at the core of our empirical investigation.We face two major empirical challenges. First, we need data that combines …nancial information with a racing environment. We use the NBER Patent Citations Data File developed by Hall, Ja¤e and Trajtenberg (2002), which records all utility patents granted in the United States between 1963 and 1999 . Every patent granted after 1975 is linked to all the patents it cites and to the CUSIP code of the assignee as it appears in COMPUSTAT. We merge the patent recor...
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