Development of tools for monitoring genetic
structure of cattle populations.
The blood typing laboratories are now
beginning to use micro-satellite markers as an alternative
to serology for parentage verification, and are selecting
a common set to be used from the several hundred micro-satellite
markers available that cover the bovine genome, produced
as part of the Bovine genome mapping project (See BovMaP).
Work with micro-satellite markers has shown that they are
valuable tools for examining genetic diversity and phylogeny
in many species. However, for work carried out in different
laboratories to be comparable, it is essential that the
same markers are used.
To maintain the compatibility of data generated by the various
typing labs, it is essential that all laboratories adopt
the same markers and typing protocols. It is therefore of
paramount importance that the blood typing laboratories
and research labs that are examining the genetic structure
of the cattle populations adopt a common panel of the best
micro-satellite markers available. Some pilot comparative
work has been undertaken through the International Society
for Animal Genetics, but so far this has only involved the
blood typing laboratories.
One objective of this project is to facilitate
the comparison of the micro-satellite markers currently
in use in the different types of laboratory and determine
the efficiency of the markers available in revealing genetic
differences within and among breeds. It will also be important
to compare the use of markers in different laboratories
to determine how robust they are and how easily results
can be compared. From comparison of the markers, those that
are most suitable will be selected to form a panel which
will be recommended for pedigree validation and genetic
surveys.
Survey of present structure of cattle
breeds in Europe with reference to DNA markers.
Participant laboratories will interact
with breed societies, breeders and blood typing laboratories
to collect blood samples from as many breeds as possible.
Many of these samples are already available in the participating
laboratories. However, it is likely that the compilation
of breeds in Europe will highlight breeds that are not already
included. Wherever possible, 40 individuals will be sampled,
with breeds occurring at more than one distinct geographical
location treated independently.
Samples of blood will be sent to the blood typing laboratories
in the project for typing with traditional markers. DNA
will be extracted from blood samples and will be made available
to all labs using DNA markers. Results from blood typing
and DNA genotyping will be shared for analysis, and results
published as part of a public access database. Recommendation
for further action will be made where appropriate.
Contribution to objectives of programme.
Cattle are an important source of food
in Europe, and intense selection has resulted in the development
of specialised breeds. Selection for high-producing dairy
cattle has been successful, but one associated drawback
is that the cattle population, both in Europe and North
America, has
been skewed dramatically towards one breed, the Holstein/Friesian.
So there has been a decline in the number of individuals
of other breeds, and hence a general erosion of the gentic
base of the cattle population. The progressive move towards
the North American-type Holstein animals has also resulted
in the requirement for high input/high output farming and
intensive management schemes. The impact of this on the
environment has been significant, e.g. pollution problems
arising from the need for high nitrogen fertilisers to produce
sufficient high quality fodder, and disposal problems associated
with slurry waste. Poorer areas of the community have been
unable to compete with such farming systems, and are more
suited to low input/low output farming using
traditional stock.
It is however the future perspective that
is of greatest concern. It is impossible to predict requirements
for cattle production - quality, production type, management
systems, etc.. The ability to switch rapidly to alternative
production will be dependent on the genetic base of the
population available to selection programmes. It is therefore
essential to maintain the greatest genetic diversity possible
in the cattle population. Whilst current farming practices
are perceived to be both efficient and acceptable, the breeds
less favoured by commercial farmers will dwindle. It is
therefore important that on an European scale efficient
management of these breeds maintains the widest genetic
base possible. This project aims to carry out a survey of
the current genetic base of the European cattle population
and to provide the tools to assist breeding programmes to
maintain a broad base.
Reason for community support.
The work described here is not of immediate
commercial interest, although in the long term it could
prove to be essential to commercial development of the cattle
industry. Nevertheless, it is a topic that is being addressed,
albeit on a small scale, by a large number of laboratories.
The coordination of these laboratories will enable a survey
of most breeds and areas in Europe to be carried out. The
Concerted Action Project will enable interaction and pooling
of expertise and standardisation of approaches to enable
the efficient use of the limited resources available to
the particpating laboratories.
It is hoped that the outputs from the project will highlight
areas where the community can be active in planning future
livestock development.
