RESUMO
Quarter horses (QH), a prominent athletic breed in Brazil, are affected by muscular genetic disorders such as myosin-heavy chain myopathy (MYHM), polysaccharide storage myopathy (PSSM1), hyperkalemic periodic paralysis (HyPP), and malignant hyperthermia (MH). Bull-catching (vaquejada), primarily involving QH, is a significant equestrian sport in Brazil. Since the allele frequencies (AF) of MYHM, PSSM1, HyPP, and MH in vaquejada QH remain unknown, this study evaluated the AF in 129 QH vaquejada athletes, specifically from the Brazilian Northeast. These variants were exclusively observed in heterozygosity. The MYHM exhibited the highest AF (0.04 ±0.01), followed by PSSM1 (0.01 ±0.01) and the HyPP variant (0.004 ±0.01), while the MH variant was not identified in this study. This study represents the first identification of these variants in vaquejada QH, emphasizing the need to implement measures to prevent the transmission of pathogenic alleles and reduce the occurrence of clinical cases of these genetic diseases.
RESUMO
The sheer diversity of heritable physiological traits, and the ingenuity of genome derived research technologies, extends the study of genetics to impact diverse scientific fields. Equine science is no exception, experiencing a number of genome-enabled discoveries that spur further research in areas like nutrition, reproduction, and exercise physiology. Yet unexpected findings, especially those that over-turn commonly held beliefs in the horse industry, can create challenges in outreach, education and communication with stakeholders. For example, studies of ancient DNA revealed that the oldest domesticated equids in the archeological record were in fact another species, the Przewalski's horse, leaving the origins of our modern horses a mystery yet to be solved. Genomic analysis of ancestry can illuminate relationships older than our prized pedigree records, and in some cases, identify unexpected inconsistencies in those pedigrees. Even our interpretation of what constitutes a genetic disease is changing, as we re-examine common disease alleles; how these alleles impact equine physiology, and how they are perceived by breeders and professionals in the industry. Effectively translating genetic tools for utilization in horse management and preparing our community for the debate surrounding ethical questions that may arise from genomic studies, may be the next great challenges we face as scientists and educators.
Assuntos
Genoma , Genômica , Animais , DNA Antigo , Cavalos/genética , LinhagemRESUMO
A paralisia periódica hipercalêmica (HYPP) é uma das principais enfermidades genéticas de caráter dominante que acometem cavalos da raça Quarto de milha (QM). A HYPP é causada por uma mutação pontual no gene SCN4A e, apesar de estar presente nos cavalos QM no Brasil, dados sobre a prevalência da HYPP são escassos. O objetivo deste trabalho foi verificar a prevalência da mutação responsável pela HYPP em cavalos QM, utilizados nas modalidades esportivas de rédeas (n=160), apartação (n=160), tambor e baliza (n=160), corrida (n=160) e conformação (n=101). Foram utilizados DNA sanguíneo dos 741 equinos; o teste genético para enfermidade foi padronizado e as amostras sequenciadas para identificação da mutação no gene alvo. A prevalência de HYPP na população amostrada foi de 4,2%, sendo que somente na linhagem de conformação foram identificados animais positivos (30,7%). Medidas de controle mais efetivas devem ser adotadas para diminuir a prevalência da HYPP.
Hyperkalemic Periodic Paralysis (HYPP) is one of the major dominant genetic diseases which affect Quarter horses (QH). The HYPP is caused by a point mutation in the SCN4A gene and despite the presence of HYPP in Brazilian QH, limited data on the disease prevalence are available. The aim of this study was to investigate the HYPP mutation in QH belonging to reining (n=160), cutting (n=160), barrel racing (n=160), racing (n=160) and halter (n=101) competitive disciplines. Blood DNA from 741 horses were used. Genetic tests were standardized and samples were sequenced to identify the mutation on the target gene. The prevalence of HYPP on the sampled population was 4.2% and the positive animals (30.7%) were only identified in the halter lineage. More effective actions on HYPP control should be done to reduce the disease prevalence. .
