RESUMEN
The pearl oyster Pinctada fucata is an important commercial marine shellfish that is cultured for producing saltwater pearls. In this study, 468 single nucleotide polymorphisms (SNPs) were screened from P. fucata transcriptome data, and 119 polymorphic SNPs were successfully isolated by a two-step small-amplicon high-resolution melting assay. Of these, 88 were annotated with BLAST in the Nr database and 90 were in the open reading frame, including 16 non-synonymous SNPs and 74 synonymous SNPs; 12 SNPs were in the 3'-untranslated region (UTR) and 1 was in the 5'-UTR. Twenty-five SNPs were randomly chosen to test the genetic diversity of 40 wild individuals from Liusha Bay, China. All of the loci had two alleles. The observed and expected heterozygosities ranged from 0.0417 to 0.6042 and from 0.2945 to 0.5053, respectively. Minor allele frequencies ranged from 0.1771 to 0.5000, and the polymorphism information content ranged from 0.2516 to 0.3750. These novel SNP markers can contribute to P. fucata genetics and breeding studies.
Asunto(s)
Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Desnaturalización de Ácido Nucleico/genética , Sistemas de Lectura Abierta/genética , Pinctada/genética , Polimorfismo de Nucleótido Simple/genética , Animales , Marcadores Genéticos , Técnicas de GenotipajeRESUMEN
The pearl oyster Pinctada fucata is a commercially important marine shellfish. As a result, genetic improvement and selective-breeding program have been conducted for this species. Polymorphic microsatellites are effective molecular markers to investigate molecular marker-assisted selection and genetic variance. In this study, microsatellite DNAs were screened and characterized based on the partial genome sequence of P. fucata. We identified 111 microsatellite DNA motifs through mining the published draft genome sequence of P. fucata. Forty-two loci were screened with 8 P. fucata individuals, and 15 were found to be polymorphic and were therefore further evaluated using 40 wild individuals from the Daya Bay, Shenzhen City, Guangdong Province, China. The number of alleles per locus ranged from 3 to 8, with an average of 5.2667 for the 15 polymorphic loci. Observed and expected heterozygosities ranged from 0.1154 to 0.6216 (0.3321 on average) and 0.4950 to 0.8491 (0.6768 on average), respectively. Of the 15 polymorphic loci, 12 loci deviated from Hardy-Weinberg equilibrium after Bonferroni correction (P < 0.0033). Polymorphism information content ranged from 0.44 to 0.83 with a mean value of 0.63. The results suggest that the markers isolated in this study can be used for research on molecular marker-assisted selection and genetic variance of P. fucata.
Asunto(s)
Sitios Genéticos , Repeticiones de Microsatélite/genética , Pinctada/genética , Polimorfismo Genético , Animales , Pruebas GenéticasRESUMEN
Skeletal muscle growth is regulated by both positive and negative factors, such as myogenic regulatory factors (MRFs) and myostatin (MSTN), and involves both hyperplasia and hypertrophy. In the present study, morphological changes during muscle development in Megalobrama amblycephala were characterized and gene expression levels were measured by quantitative real-time polymerase chain reaction (qRT-PCR) analysis in juvenile [60, 90, 120, and 180 days post-hatching (dph)] and adult fish. Our results show that during muscle development, the frequency of muscle fibers with a diameter <20 µm dramatically decreased in both red and white muscles, with a concomitant increase in the frequency of >30 µm fibers in red muscle and >50 µm fibers in white muscle. At 90-120 dph, the ratio of hyperplastic to hypertrophic areas in red and white muscles increased, but later decreased at 120-180 dph. The effect of hypertrophy was significantly larger than hyperplasia during these phases. qRT-PCR indicated MRF and MSTN (MSTNa and MSTNb) genes had similar expression patterns that peaked at 120 dph, with the exception of MSTNa. This new information on the molecular regulation of muscle growth and rapid growth phases will be of value to the cultivation of M. amblycephala.