Genetic anomalies emerge on a regular basis in livestock populations. Their appearance is practically inevitable.They are the result of DNA mutations that we cannot control. Even though they are not heterozygous (the mutation is then considered as being recessive), they can spread in a population over several generations without being recognized. Active surveillance is therefore necessary to detect these emerging abnormalities remembering that these first cases are detected late and are always made after the original mutation has occurred and spread throughout a population.
Searching for a mutation responsable for a specific anomaly requires several steps :
1) Identification of the emergence
2) Clinical description of the anomaly. This is a crutial step in order to guarentee the uniqueness of the pathology studied and to choose the appropriate direction for the genetic research
3) Sample collection (blood, ears, ....) from affected individuals in order to obtain DNA
4) Genetic analyses using genotyping and sequencing
Much progress has been made recently in genomics tools, providing a way to isolate a gene responsable for an anomaly much more rapidly. A diagnostic DNA test which allows the identification of diseases, carrier and non-carrier animals, is the only efficient way to eradicate anomalies in a population.
The first steps of observation of an emergence, clinical characterisation and sampling are the most difficult and require organisation and coordination and the intervention of many different actors on the field. Cécile Grohs (INRA) and Coralie Danchin (Institut de l'Elevage) are in charge of these observations coordinated by the National Observatory for Bovine Anomalies.
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