Validation of commercial DNA tests for beef quality traits

Abstract

Gene mapping and discovery programs have resulted in the detection of numerous DNA "˜markers' for various beef cattle production traits. Prior to commercializing genetic markers, it is important to validate their purported effects on the traits of interest in different breeds and environments, and assess them for correlated responses in associated traits. One of the biggest challenges in achieving this objective is the availability of cattle populations with sufficient phenotypic data to assess the association between various traits and newly discovered genetic markers. Results from such validation studies to date have not been widely published and genetic marker tests sometimes may be commercialized prior to the collection of field validation data. In addition, conflicting reports about some commercially available markers, as well as the recognized occurrence of well-proven bulls with a high EPD for a given trait but carrying two copies of the "wrong"? (unfavorable) marker for that trait, have made some producers wary of investing in DNA-based testing. Producers want to know whether DNA-based tests perform in accordance with the claims of the marketing company and are interested in third-party, independent validation of these tests. The objective of this study was to validate three commercially-available genetic tests (GeneSTAR Quality Grade8, GeneSTAR Tenderness8, and Igenity TenderGENE9).

Association of CAPN1 316, CAPN1 4751 and TG5 markers with bovine meat quality traits in Mexico

“…The present study obtained a very low frequency for the TG5 T allele; several authors have reported low frequencies in this IMF favorable allele in B. indicus cattle (from 0.03 to 0.10), as opposed to those reported for Wagyu cattle, characterized by its intramuscular fat known as marbling (Thaller et al, 2003;Barendse et al, 2004;Casas et al, 2005Casas et al, , 2007Van Eenennaam et al, 2007).…”

“…Although genotype-linked segregation might be misinterpreted, this does not necessarily indicate segregation of favorable alleles (Parra-Bracamonte et al, 2009). The availability of commercial panels for markers associated with quantitative traits could change the reported frequency basis in the future (Quaas et al, 2006), and validation studies (Van Eenennaam et al, 2007) could promote the implementation of markers as selection tools.…”

“…Nowadays, improvement strategies include the use of molecular markers to assist genetic selection and management of carrieranimals for favorable allelic variants associated with quantitative traits difficult or expensive to measure, such as the meat quality traits, in particular tenderness and marbling (Meuwissen and Goddard, 1996;Van Eenennaam et al, 2007).…”

Genetic polymorphisms related to meat traits in purebred and crossbred Nelore cattle

“…Also, in B. indicus populations it is not linked or in strong linkage disequilibrium with the causative polymorphism, which confi rms that polymorphism is useless in marker-assisted selection for beef herds with a broad genetic background. However, a relatively novel CAPN1 polymorphism, the CAPN4751 SNP, has shown great potential as a marker for meat tenderness selection in B. taurus, B. indicus and B. indicus x B. taurus beef herds Van Eenennaam et al, 2007). As expected, no relation between allelic forms of the CAPN1 gene and the growth and fat traits (REA, BT and IF) was found.…”

Future trends in Animal Breeding due to new genetic technologies

“…Another approach is to use markers that are in linkage disequilibrium with QTLs. Several companies are developing and releasing commercial DNA test toolboxes involving a small number of markers (Van Eenennaam et al, 2007) and some initiatives exist to combine pedigree, markers and phenotypic information (for a review, see Dekkers, 2004).…”