10 What Role Could Old/Heritage Genetics Play in Climate adaptation?

Abstract

Abstract Creole or Criollo breeds descend directly from cattle introduced by the Spanish and Portuguese conquerors in the XVth century, being the only cattle breeds in the Americas that have endured 500 years of natural selection to local conditions. Their genetic background includes Iberian and African taurine breeds. This ancestry combined with local adaptations to a very wide variety of environments throughout all the continent created the wide spectrum of American Criollo breeds that we see today, from USA to the Patagonian region. Criollo cattle was the basis of colonial times livestock industry until they were displaced by more specialized European and cebuine type cattle breeds at the end of the 19th century. Efforts by local producers and research institutions helped to preserve Criollo populations and to avoid their extinction. Most of Criollo animals were relegated to marginal regions unsuitable for commercial breeds, which reinforced their ability to adapt to unfavorable environments. Their adaptation to different environments allowed the expression of high levels of genetic variability, being a source of hidden alleles of potential use in animal production and thus very important to study and preserve. The analysis of nuclear and cytoplasmic markers, such as SNP, microsatellites and mitochondrial DNA, has allowed estimations of genetic diversity, admixture events with other breeds, and the elucidation of genetic relationships within Criollo breeds and with European and African breeds. Criollo breeds differ considerably from each other, and most have their own identity or group with others from neighboring regions. These results indicate that Criollo breeds represent important reservoirs of cattle genetic diversity and that appropriate conservation measures should be implemented for these heritage breeds to minimize inbreeding and uncontrolled crossbreeding. Several studies have demonstrated that these animals can produce high quality meat, are more resistant to diseases and heat stress, and emphasize their high fertility, calving ease, longevity and ability to adapt to harsh environments, including arid regions. More studies are needed to elucidate the genetic basis of these traits. Properly managed, Criollo cattle “old genetics” can certainly be part of the solution to modern livestock production problems.