No abstract

Genetic analysis of Trypanosoma spp. depends on the detection of variation between strains. We have used the amplified fragment length polymorphism (AFLP) technique to develop a convenient and reliable method for genetic characterization of Trypanosome (sub)species. AFLP accesses multiple independent sites within the genome and would allow a better definition of the relatedness of different Trypanosome (sub)species. Nine isolates (3 from each T. brucei subspecies) were tested with 40 AFLP primer combinations to identify the most appropriate pairs of restriction endonucleases and selective primers. Primers based on the recognition sequences of EcoRI and BglII were chosen and used to analyse 31 T. brucei isolates. Similarity levels calculated with the Pearson correlation coefficient ranged from 15 to 98 %, and clusters were determined using the unweighted pair-group method using arithmetic averages (UPGMA). At the intraspecific level, AFLP fingerprints were grouped by numerical analysis in 2 main clusters, allowing a clear separation of T. b. gambiense (cluster I) from T. b. brucei and T. b. rhodesiense isolates (cluster II). Interspecies evaluation of this customized approach produced heterogeneous AFLP patterns, with unique genetic markers, except for T. evansi and T. equiperdum, which showed identical patterns and clustered together.

Gene therapies hold great promise for treatment of diseases but so far their market authorisation has been limited. This paper describes the development of patented gene therapies in the sector of life sciences and health.  It was found that the annual number of patented gene therapies increased significantly till the year 2005.  A cluster analysis of gene therapies patented in 1995 shows that:  a) more than eighty percent has been renewed for more than fifteen years (fifty three per cent till the maximum patent term) and b) fifty per cent of the patents have been licensed. There is a statistically significant correlation between the numbers of citations in future patent applications by third parties and the number of years of patent renewals. A case study of the patent EP 0833934 of biotechnology start- up Crucell demonstrates that the number of citations by third companies to this patent even predicts the companies’ market capitalization. This research yielded evidence that the number of patent citations can be used as indicator to determine the value of gene therapies. Such information is of relevance for both the patentee and investors.