The project, Resource Centres for YAC libraries, aims to: firstly establish an efficient system for the provision of YAC clones to European laboratories by means of YAC libraries Resource Centres, and then to screen the available YAC libraries upon request of applicants from EC countries. This will improve the physical mapping projects of the EC laboratories and the characterization of new genes implicated in hereditary diseases. This project consists of five EC based laboratories.
Research was carried out in order to establish yeast artificial chromosome (YAC) library screening centres and to screen the available YAC libraries upon request of applicants from European Community (EC) countries.
More than 300 collaborations have been established between Centre d'Etude du Polymorphisme Humain (CEPH) and laboratories requesting screenings and/or YACs. The YAC library has been primordial to characterize disease genes and for the first time the entire Major Histocompatibility Complex was isolated in terms of overlapping clones and the first physical map of the human leucocyte antigen (HLA) class I region in YACs was prepared.
A new approach was developed to isolate chromosome specific YAC subsets. It is based on the hybridization with Alu polymerase chain reaction (PCR) products. Screening of YACs with Alu PCR products amplified from hybrid cell lines containing only human chromosome 21 allowed identification of chromosome 21 specific YACs. These results indicate that when a megabase insert human genome YAC library is available, it can be rapidly and accurately subdivided into chromosome specific sublibraries and, will permit quick assembly of large contigs.
CEPH also reported a whole genome approach for mapping the human genome. 22 000 YACs have been fingerprinted to obtain individual patterns of restriction fragments detected by a LINE-1 (L1) probe. CEPH also was the first to isolate a whole human chromosome in terms of overlapping YACs. In total 198 sequence tagged sites (STS) were used to screen the library. 810 clones were isolated and characterized. They cover all the long arm of human chromosome 21. This result demonstrates the good representativity of the library and indicates that this strategy can be performed for all the other chromosomes.
The characterized YAC clones will be sent to the EC applicants for their own further study accompanied by some indications concerning the growth and storage of the clones.
At the end of the contract period the five established YAC Resource Centres will have tested more than one thousand probes: 250 for CEPH (Paris), 400 for ICRF (London), 200 for HGMPRC (Harrow), 100 for CNR (Pavia) and 100 for University of Leiden.
The achievements and target of this project will be monitored in terms of number of probes tested and number of characterized YAC clones.
Data, from all participants, on probes used and clones characterized will be registered in a common YAC relational database and will be in the public domain either immediately, if the probes or primers involved are published, or after a time period to be defined (probably six months) if the probes are not yet published.
Data will be made available using a number of channels (newsletter, electronic mail and possibly on line access).
Funding SchemeCSC - Cost-sharing contracts
HA1 3UJ Harrow
WC2A 3PX London
2300 RA Leiden