Exploring genetic diversity: New indicators proposed for animal cryobanks

This study proposes an analytical framework based on new indicators to assess the usefulness of cryopreserved collections from a conservation support perspective by i) evaluating its level of diversity and intrinsic redundancy, and ii) its originality relative to on-farm populations. For the first approach, equitability indices based on Gini-Simpson indices revealed an unbalanced number of donors between breeds for certain species. Similarly, estimates of the effective number of donors (De) derived from these indices revealed an uneven distribution of donors within breeds. For the second point, we have developed a new Diversity Impact Index (DII) to assess the potential of a collection to reintroduce genetic diversity into contemporary populations. When calculated individually, it can then be used to optimize the choice of individuals to be used. Here, it has been calculated from the pedigrees of 17 breeds of three species (pigs, sheep and cattle), but can also be obtained from genotyping data in the absence of pedigrees.

In general, older collections had the most favorable IDI values, but recently collected donors could still be useful for populations subject to strong selection. Compared with FAO indicators driven by breed reconstitution, equitability indices and De enable more efficient sampling planning, while IDI can guide donor selection to manage on-farm population diversity.

Contact : 
• Alicia Jacques, Michèle Tixier-Boichard, Gwendal Restoux

Reference : 
Assessing the potential of germplasm collections for the management of genetic diversity: the case of the French National Cryobank. Alicia Jacques, Delphine Duclos, Coralie Danchin-Burge, Marie-Jose Mercat, Michèle Tixier-Boichard, Gwendal Restoux. Peer Community Journal, Volume 4 (2024), article no. e13. https://doi.org/10.24072/pcjournal.369