Chronological Expression of PITX2 and SIX1 Genes and the Association between Their Polymorphisms and Chicken Meat Quality Traits

Meat quality is closely related to the development of skeletal muscle, in which PITX2 and SIX1 genes play important regulatory roles. The present study firstly provided the data of chronological expression files of PITX2 and SIX1 genes in the post-hatching pectoral muscle and analyzed the association of their polymorphisms with the meat quality traits of Wuliang Mountain Black-bone (WLMB) chickens. The results showed that both PITX2 and SIX1 genes were weakly expressed in the second and third weeks, and then increased significantly from the third week to the fourth week. Furthermore, there was a significant positive correlation between the expression levels of the two genes. Twelve and one SNPs were detected in the chicken PITX2 and SIX1 genes, respectively, of which four SNPs (g.9830C > T, g.10073C > T, g.13335G > A, g.13726A > G) of the PITX2 gene and one SNP (g.564G > A) of the SIX1 gene were significantly associated with chicken meat quality traits. For the PITX2 gene, chickens with the CT genotype of g.9830C > T showed the highest meat color L*, shear force (SF), pH, and the lowest electrical conductivity (EC), and drip loss (DL) (p < 0.05 or p < 0.01); chickens with the CC genotype of g.10073C > T had the lowest L*, pH, and the highest DL (p < 0.01). For the SIX1 gene, chickens with the GG genotype of g.564G > A had the highest (p < 0.05) SF and pH. Furthermore, pH had a significant correlation with all the other meat quality traits. The current study could contribute to the research of regulatory mechanisms of meat quality and lay the foundation for improving meat quality based on marker-assisted selection in chickens.

Expression Analysis of the PITX2 Gene and Associations between Its Polymorphisms and Body Size and Carcass Traits in Chickens

PITX2 is expressed in and plays an important role in myocytes of mice, and it has effects on late myogenic differentiation in chickens. However, the expression profile and polymorphisms of PITX2 remain unclear in chickens. Therefore, the aim of the present study was to detect its expression and investigate single nucleotide polymorphisms (SNPs) within its exons and then to evaluate whether these polymorphisms affect body size as well as carcass traits in chickens. The expression analysis showed that the expression level of chicken PITX2 mRNA in the leg muscle and hypophysis was significantly higher (p < 0.01) than those in other tissues. The results of polymorphisms analysis identified two SNPs (i.e., g.9830C > T and g.10073C > T) in exon 1 and 10 SNPs (i.e., g.12713C > T, g.12755C > T, g.12938G > A, g. 3164C > T, g.13019G > A, g.13079G > A, g.13285G > A, g.13335G > A, g.13726A > G and g.13856C > T) in exon 3, including four novel SNPs (i.e., g.9830C > T, g.12713C > T, g.12938G > A and g.13856C > T). In the loci of g.10073C > T and g.12713C > T, chickens with the CT genotype had the highest (p < 0.05 or p < 0.01) breast depth and breast angle, respectively. For the locus of g.13335G > A, chickens with the GG genotype had the highest (p < 0.05 or p < 0.01) breast angle and shank circumference. For the locus of g.13726A > G, chickens with the GG genotype had the highest breast width, fossil keel bone length and shank circumference. The locus of g.12713A > G had significant effects on the PITX2 mRNA expression level in leg muscle. The H1H7 diplotype showed the highest shank circumference, and the H2H8 diplotype showed the highest breast muscle rate. The present research suggested that polymorphisms of the exons of the PITX2 gene were significantly associated with the body size and carcass traits of Wuliang Mountain Black-bone chickens and the PITX2 gene could be a potential candidate gene for molecular marker-aided selection in Wuliang Mountain Black-bone chickens and other chicken breeds.

Homatula wuliangensis (Teleostei: Nemacheilidae), a new loach from Yunnan, China

A new species of Homatula, Homatula wuliangensis, is described from the Lancang River of the Wuliang Mountain, Pu-Er City, Jingdong County, Yunnan Province, China. Homatula wuliangensis sp. nov. is readily distinguished from otherspecies of Homatula by the combination of several morphological characters, including a long upper lobe of the caudalfin relative to the lower lobe, high and long dorsal adipose crest, series of 22–26 very closely aligned body markings, bodyscaled, and 41–42 vertebrae. In addition, H. wuliangensis differs from the similar species H. anguillioides in having short-er barbels, spots on the caudal fin, the origin of the pelvic fin under the last simple dorsal-fin ray, and a pointed axillarypelvic lobe divided from the body. The new species is further distinguished from the similar species H. pysnolepis in having shorter barbels, lacking a notch on the lower jaw, and lacking vermiform markings on top of the head.

Conservation of the black-crested gibbon in China

The black-crested gibbon is believed to be endangered throughout its range in China and northern Vietnam, where much of the original forest has been destroyed. The only reserves known to have substantial populations are the Ailao Mountain and Wuliang Mountain Natural Protected Areas in Yunnan Province, China, which together may have 1500 of an estimated total of 3500 black-crested gibbons in protected areas in China. Although they are probably the best protected, the gibbon populations of both reserves have been badly depleted by deforestation and hunting. Recent reports that roads will be constructed through the centres of the reserves, and that gold has been discovered in one of them, increase concern. The Ministry of Forestry has started new conservation measures, but further action is required.