PSXII-6 - Landscape genetics used to identify gene bank beef cattle collection completeness and gaps

Gene banks (GB) primary goal is to capture genetic diversity among livestock breeds. Genetic diversity assessments by US GB have used pedigrees and genetic markers. Landscape genetics (LG), is a third approach for evaluating germplasm collections and genetic resources. We evaluated the GB’s beef collection using LG for the purpose of assessing collection gaps/completeness by using geographic information systems. The current beef cattle collection contains 3,916 animals from 11 Bos indicus (including composite, BI), and 40 Bos taurus British (BTB) and Bos taurus continental (BTC) breeds. Each GB animal was georeferenced by latitude and longitude. In addition, county level satellite imagery of the continental US was obtained and included: temperature, humidity, precipitation, and normalized difference vegetation index (NDVI). Temperature–humidity index (THI) was computed from temperature and humidity by county. In addition, USDA beef cattle statistics by county were used in mapping overlays. There was a high correspondence between in-situ cattle density and GB collection throughout the mid-west and extending to both borders. Evaluating genetic groups demonstrated that BI were derived from the Gulf Coast region, while BTB and BTC shared a distribution throughout the mid-west. The collection’s BTB were also sourced from the inter-mountain west. All environmental parameters were combined to identify similar environmental conditions where germplasm had already been collected. Through this process future geographies for sampling genetic groups were apparent. New collection areas should include the Great Basin, west Texas, New Mexico and Arizona. Further BI collections should be performed in low THI score areas and BTB and BTC collections in high THI areas is needed. Using GIS/LG adds a new perspective and resolution for future collections to ensure cattle that are adapted to a particular environment are added to the collection.