Genetic diversity of Chinese native chicken breeds based on protein polymorphism, randomly amplified polymorphic DNA, and microsatellite polymorphism.

Genetic diversity of Chinese native chicken breeds was investigated using protein polymorphism, randomly amplified polymorphic DNA (RAPD), and microsatellite polymorphism. Imported broiler and layer breeds were also included in the analysis. The results from protein polymorphism did not show distinct differences between Chinese native chicken and imported broilers; however, there were small significant differences between these two types of chickens. The results from RAPD indicated that gene diversity within a population was large in Chinese native chickens, intermediate in broilers, and low in layers and that there were small differences between Chinese native chickens and both broilers and layers. A great difference between broilers and layers was observed. Microsatellite polymorphism data showed that genetic diversity was high in the Chinese native chickens and low in layers and that there was a close relationship between Chinese native chickens and broiler but a remote relationship between Chinese native chickens and layers. The wide genetic diversity of Chinese native breeds can meet different requirements of breeding for chicken quality in China.

Comparative analysis of allozyme, random amplified polymorphic DNA, and microsatellite polymorphism on Chinese native chickens.

Allozyme, random amplified polymorphic DNA (RAPD), and microsatellite polymorphisms were examined and compared among five native populations of Chinese chickens, two fast-growing broiler lines, and one layer line. Three assay systems resulted in a different average heterozygosity or gene diversity in each of the eight populations. The lowest average heterozygosity was obtained with allozyme analysis (0.2209), intermediate heterozygosity was obtained with RAPD (0.2632), and the highest heterozygosity was observed with microsatellite analysis (0.7591). The genetic distances among all populations measured by three methods were also different. Allozyme data showed close relationships between Chinese native chickens and the two broiler lines, but they were both remotely related to the layer line. Microsatellite polymorphism analysis was similar to the allozyme analysis but genetic distances from RAPD showed a close relationship between Chinese native chickens and broiler and layer chickens.

Effects of dibutyryl cAMP on stanniocalcin and stanniocalcin-related protein mRNA expression in neuroblastoma cells.

Stanniocalcin is a polypeptide hormone that was first reported in fish as a regulator of mineral metabolism. Its recent identification in mammals has opened a new area of investigation in basic and clinical endocrinology. In the present study, regulation of the stanniocalcin (STC) and stanniocalcin related protein (STCrP) genes were investigated in mouse neuroblastoma cells (Neuro-2A) in relation to neuronal cell differentiation. Neuro-2A is an undifferentiated cell line that contains measurable levels of STCrP mRNA, but undetectable levels of STC mRNA. Treatment of the cells with either dbcAMP (1-4 mM) or 50 microM euxanthone (PW1) resulted in extensive differentiation and neurite outgrowth. However, only neurites of dbcAMP-treated cells developed varicosities, a phenotypic marker of axon formation. Furthermore, following differentiation induced by dbcAMP, there was an upregulation of STC and downregulation of STCrP mRNA levels. In the first 24 and 48 h of treatments, there was a maximum twofold induction and 1.5-fold reduction in STC and STCrP mRNAs respectively. Following 96 h of treatment, an additional 14-fold STC induction and 1.2-fold STCrP reduction were observed. The increase in STC mRNA levels was accompanied by a concomitant increase in axon-specific low molecular form microtubule-associated protein (MAP-2c) mRNA and varicosities on the neurites, suggesting a possible role for STC in axonogenesis. There was no induction of STC mRNA levels when PW1 was added into the culture media, whereas ionomycin (1-10 microM) had no observable effects on cell differentiation or STC/STCrP mRNA. Immunocytochemical staining of dbcAMP-treated cells revealed abundant levels of immunoreactive STC, particularly in the varicosities, with only weak staining in control, untreated cells. Antisense oligodeoxynucleotides transfection studies indicated that the expression of STC was a cause of varicosity formation and a consequence of cell differentiation. Our findings lend further support to the notion that STC is involved in the process of neural differentiation.