Chair: Matthew Binns, Animal Health Trust, United Kingdon
Location: Göttingen, Germany
Dates: August 11-15, 2002
Report on Horse Genome Mapping Workshop, ISAG Gottingen, 12/8/02
The workshop comprised eight presentations followed by a discussion of future strategies to improve the status of the horse genome maps. The workshop was very well attended, all seats in the room provided were full and the aisles were also full.
Initially, Professor Ernie Bailey (University of Kentucky) informed the group of the resources that are available to the horse mapping community (primers, BAC libraries, EST sequences, etc). He also described two meetings (PAG in San Diego and Havermeyer in Brisbane) at which horse geneticists had met since the last ISAG meeting.
There then followed three talks concerning the current status of the horse maps. Dr Gerard Guerin (INRA, France) described the International half-sibling map, where a paper has been submitted for publication that includes 344 markers (7 blood markers, 10 biochemical markers, 325 microsatellites and 2 SSCP markers). 310 markers (90%) have been linked together, 257 markers ordered on 34 linkage groups, and 185 markers are in common with the published "Newmarket" map. All the markers in common map to the same chromosomes and linkage groups, with only modest differences in distances and local order. Dr June Swinburne (AHT, Newmarket) then described progress on the "Newmarket" full-sibling linkage map. Currently 717 markers have been genotyped, of which only 13 (1.8%) are not linked to another marker at LOD 3. Multipoint maps are under construction and an example for ECA16 was presented which had roughly double the number of markers present on the published map and a greatly extended genetic distance. Only 4 gaps exist in the map, in terms of multiple linkage groups on single chromosomes, and work is underway to try to fill these gaps, using the newly generated 11x BAC library. The contribution of the Japanese and University of Minnesota groups was acknowledged, in providing a large number of new microsatellites for the mapping work. Dr Bhanu Chowdhary (Texas A&M) reported on the progress of the horse radiation hybrid map project. Approximately 1000 markers have been typed and a map containing about 700 markers is under construction. Examples of maps for ECA8, 10 and 13 were provided, and a conservative approach was being taken in relation to not trying to "force" the joining of groups of markers into a single group per chromosome. The RH map provides excellent resolution of the comparative genome map as 320 of the markers typed are genes.
Dr Guerin then described work in press involving the cytogenetic mapping of 136 new genes, largely through FISH mapping horse and goat BAC clones containing specific genes. Work is continuing to target genes at ~10cM intervals.
Lee Millon (University of California, Davis) described horse related research in Davis, including the possible identification of the mutation for cream dilution coat colour, and a linked marker for dun coat colour. New microsatellite markers are being developed and mapped in collaboration with Dr Tozaki (Japan). Primers for these markers have been designed with the M13 tag system with considerable cost savings. Advantages of using the SOLAR program for genetic mapping, in terms of handling complex pedigrees and input of Crimap .gen files was described.
Dr Tozaki (JRA, Japan) reported on a new technique for enriching for microsatellite containing clones, using it to isolate large numbers of di- and tri- nucleotide microsatellite repeat containing clones. The tri-nucleotide repeats were generally poorly polymorphic, confirming unpublished findings from Dr Eggleston (UC Davis) who had also found tri and tetra nucleotide repeats to be poorly polymorphic in the horse.
Lastly, Natasha Ellis (University of Sydney) reported on her research studying the horse ACE gene, which forms part of her PhD work. This gene has been associated with physiological performance in man and is being investigated as a candidate performance gene in horses. A BAC clone containing the horse gene has been isolated in collaboration with Dr Guerin and the majority of the exons and introns have been sequenced. Future plans include investigating polymorphism in Thoroughbred and Arab endurance horses.
An invitation for further contributions from the floor elicited a response from Clare Gill (Texas A&M) who described a new browser based genome viewer that allows global results of BLAST searches to be visualised. The viewer should be available on line within the next few months. Other new members to the horse group described their interest in inherited disease problems, including osteochondrosis (OCD), chronic obstructive pulmonary disease (COPD - recently renamed recurrent airway obstruction RAO) and fertility problems.
The workshop was characterised by lively discussion following all the presentations, and a general willingness to co-operate between all the participants. Plans were advanced for a meeting to integrate the existing maps. The Chairman thanked the presenters and the audience for making the workshop so productive.
Matthew Binns, Chairman
