RESUMO
BACKGROUND: Size of reference population is a crucial factor affecting the accuracy of prediction of the genomic estimated breeding value (GEBV). There are few studies in beef cattle that have compared accuracies achieved using real data to that achieved with simulated data and deterministic predictions. Thus, extent to which traits of interest affect accuracy of genomic prediction in Japanese Black cattle remains obscure. This study aimed to explore the size of reference population for expected accuracy of genomic prediction for simulated and carcass traits in Japanese Black cattle using a large amount of samples. RESULTS: A simulation analysis showed that heritability and size of reference population substantially impacted the accuracy of GEBV, whereas the number of quantitative trait loci did not. The estimated numbers of independent chromosome segments (Me) and the related weighting factor (w) derived from simulation results and a maximum likelihood (ML) approach were 1900-3900 and 1, respectively. The expected accuracy for trait with heritability of 0.1-0.5 fitted well with empirical values when the reference population comprised > 5000 animals. The heritability for carcass traits was estimated to be 0.29-0.41 and the accuracy of GEBVs was relatively consistent with simulation results. When the reference population comprised 7000-11,000 animals, the accuracy of GEBV for carcass traits can range 0.73-0.79, which is comparable to estimated breeding value obtained in the progeny test. CONCLUSION: Our simulation analysis demonstrated that the expected accuracy of GEBV for a polygenic trait with low-to-moderate heritability could be practical in Japanese Black cattle population. For carcass traits, a total of 7000-11,000 animals can be a sufficient size of reference population for genomic prediction.
Assuntos
Genômica , Modelos Genéticos , Animais , Bovinos/genética , Genótipo , Fenótipo , Polimorfismo de Nucleotídeo Único , Locos de Características QuantitativasRESUMO
Hydrallantois is the excessive accumulation of fluid in the allantoic cavity in a pregnant animal and is associated with fetal death. We recently identified a recessive missense mutation in the solute carrier family 12, member 1 (SLC12A1) gene (g.62382825G>A, p.Pro372Leu) that is associated with hydrallantois in Japanese Black cattle. Unexpectedly, we found a case of the homozygous risk-allele for SLC12A1 in a calf, using a PCR-based direct DNA sequencing test. The homozygote was outwardly healthy up to 3 months of age and the mother did not exhibit any clinical symptoms of hydrallantois. In order to validate these observations, we performed confirmation tests for the genotype and a diuretic loading test using furosemide, which inhibits the transporter activity of the SLC12A1 protein. The results showed that the calf was really homozygous for the risk-allele. In the homozygous calf, administration of furosemide did not alter urinary Na+ or Cl- levels, in contrast to the heterozygote and wild-type calves in which these were significantly increased. These results demonstrate that the SLC12A1 (g.62382825G>A, p.Pro372Leu) is a hypomorphic or loss-of-function mutation and the hydrallantois with this mutation shows incomplete penetrance in Japanese Black cattle.
Assuntos
Alantoide , Doenças dos Bovinos/genética , Bovinos/genética , Diurese , Edema/genética , Edema/veterinária , Furosemida , Estudos de Associação Genética/veterinária , Homozigoto , Mutação de Sentido Incorreto/genética , Complicações na Gravidez/genética , Complicações na Gravidez/veterinária , Simportadores de Cloreto de Sódio-Potássio/genética , Membro 1 da Família 12 de Carreador de Soluto/genética , Alelos , Animais , Diurese/efeitos dos fármacos , Diurese/genética , Edema/fisiopatologia , Feminino , Morte Fetal/etiologia , Furosemida/farmacologia , Genes Recessivos/genética , Reação em Cadeia da Polimerase , Gravidez , Transporte Proteico/efeitos dos fármacos , Risco , Análise de Sequência de DNA , Membro 1 da Família 12 de Carreador de Soluto/metabolismoRESUMO
Small intestine epithelial cell lines (TR-SIE), which are established from the small intestine of transgenic rats harboring temperature-sensitive simian virus 40 large T-antigen gene (tsA58 Tg rat), were used to characterize the mRNA expression of small intestine transporters. TR-SIE cells had a polygonal morphology and expressed cytokeratin protein and villin mRNA. Although the large T-antigen was strongly expressed at 33 degrees C, this was reduced at 37 and 39 degrees C. Concomitantly, the cell growth was arrested at 37 and 39 degrees C compared with that at 33 degrees C, suggesting that TR-SIE cells are conditionally immortalized cell lines. RT-PCR analysis revealed that TR-SIE cells expressed ABCB1 (mdr1a and mdr1b), ABCB4 (mdr2), ABCC2 (mrp2), ABCC6 (mrp6), ABCG1, ABCG2 (bcrp/mxr), Slc21a7 (Oatp3), Slc15a1 (PepT1), and Slc16a1 (Mct1). Conditionally immortalized rat small intestine epithelial cell lines were established from tsA58 Tg rats and expressed the mRNA of intestinal transporters.