Genetic characterization of Rarámuri Criollo cattle from the USDA-ARS Jornada Experimental Range, Las Cruces, NM, USA

Rarámuri Criollo (RC) cattle have been raised by isolated Tarahumara
communities of Chihuahua, Mexico, for nearly 500 years, mostly under
natural selection and minimal management. The RC cattle was
introduced to the USDA Jornada Experimental Range (RCJER) in 2005 to
begin evaluations of beef production performance and their
adaptation to the harsh ecological and climatic conditions of the
Northern Chihuahuan Desert. While this research unveiled crucial
information on their phenotypic plasticity and adaptation, the
genetic diversity and structure of the RCJER population remain
poorly understood. This study analyzed the genetic diversity,
population structure, ancestral composition, and selection
signatures of the RCJER herd using a ~64K SNP array. The RCJER herd
exhibits moderate genetic diversity and low population
stratification with no evident clustering, suggesting a shared
genetic background among different subfamilies. Admixture analysis
revealed the RCJER herd represents a distinctive genetic pool within
the Criollo cattle biotypes, with significant Iberian ancestry.
Selection signatures identified candidate genes and Quantitative
Trait Loci for traits associated with milk composition, growth, meat
and carcass, reproduction, metabolic homeostasis, health, and coat
color. The RCJER population represents a distinctive genetic
resource adapted to harsh environmental conditions while maintaining
productive and reproductive attributes. These findings are crucial
to ensuring the long-term genetic conservation of the RCJER and
their strategic expansion to locally adapted beef production systems
in the US.