The genetic diversity of chicken breeds from Jiangxi, assessed with BCDO2 and the complete mitochondrial DNA D-loop region.

The Jiangxi Province of China has numerous native domestic chicken breeds, including some black skin breeds. The genetic diversity of Jiangxi native chickens is largely unknown, and specifically, the genetic contribution of the grey junglefowl to black skin chickens is not well understood. To address these questions, the complete D-loop region of the mitochondrial DNA (mtDNA) and beta-carotene dioxygenase 2(BCDO2)gene was sequenced in a total of 209 chickens representing seven Jiangxi native breeds. Thirty-one polymorphic sites were identified across the complete mtDNA D-loop region sequence. Twenty-three haplotypes were observed in the seven breeds, which belonged to four distinct mitochondrial clades (A, B, C and E). Clade A and B were dominant in the chickens with a frequency of approximately 67.9%. There were five SNPs that defined two haplotypes, W and Y in BCDO2. Four breeds had one haplotype and three breeds had two. We conclude that Jiangxi native chicken breeds have relatively low genetic diversity and likely share four common maternal lineages from two different maternal ancestors of junglefowl. Furthermore, some Jiangxi chicken populations may have been mixed with chickens with exotic lineage. Further research should be established to protect these domestic chicken resources.

[Distribution of soil organic carbon, total nitrogen, total phosphorus and water stable aggregates of cropland with different soil textures on the Loess Plateau, Northwest China]. / 黄土高原不同土壤质地农田土壤碳、氮、磷及团聚体分布特征.

In this study, combined with field investigation and laboratory analyses, we assessed the distribution of soil organic carbon, nitrogen, phosphorous contents and their stoichiometric ratios, and the distribution of soil water stable aggregates along a soil texture gradient in the cropland of the Loess Plateau to understand the effect of soil texture and the regulation of soil aggregates on soil fertility in cropland. The results showed that, with the change from fine soils to coarse soils along the texture gradient (loam clay→ clay loam→ sandy loam), the contents of macroaggregates, organic carbon, nitrogen, phosphorous and their stoichiometric ratios decreased, while pH value and microaggregates content showed an opposite changing pattern. The contents of macroaggregates, organic carbon, nitrogen, phosphorous, and C/P and N/P were significantly increased, but pH value and microaggregates content were significantly decreased with increasing the soil clay content. Furthermore, the contents of organic carbon, nitrogen, phosphorous, and C/P and N/P increased with the increase of macroaggregates content. These results indicated that soil fertility in croplands at a regional scale was mainly determined by soil texture, and was regulated by soil macroaggregates.

The investigation of genetic diversity and evolution of Daweishan Mini chicken based on the complete mitochondrial (mt)DNA D-loop region sequence.

This study evaluated the genetic diversity and origin of Daweishan Mini chickens using mtDNA sequence polymorphism. Blood samples from 30 Daweishan Mini chickens were collected. The complete D-loop was PCR amplified, sequenced and compared with the DNA data of five Red Junglefowl (Gallus gallus) subspecies. Eighteen variable sites that defined six haplotypes were observed. The six haplotypes were clustered into four clades (A, B, D and E), of which clade A and B were dominant. Clades Aand B were clustered with G.g. spadiceus, indicating these two clades may have originated from this subspecies. These results show there is diversity in the middle of the mtDNA D-loop, and indicate there are multiple maternal origins for Daweishan Mini chickens. It appears that G.g. spadiceus contributed more to the evolution of the Daweishan Mini chickens breed than the other four subspecies tested here.

[The genetic effects of IGF2 gene intron3 variance in pigs].

A mispairing PCR-RFLP technique was applied in this study to determine the Insulin-like Growth Factor 2(IGF2) gene intron3 G3072A mutation in an outbred Landrace and Large White, and the gelded boars from Landrace x Large White cross. The difference of corresponding traits and the genetic effects of the boars inherited from parental A allele and inherited from parental G allele were analyzed. The results indicated that comparing with the boars inherited from parental G allele, the boars inherited from parental A allele increased significantly in the circumference 3.06% (P< 0.05) and index of body 3.01% (P< 0.05), respectively. The boars inherited from parental A allele had a significantly less average buttock fat thickness (15.31%, P< 0.01), thorax-waist fat thickness (23.74%, P< 0.01), skin thickness 9.38% (P< 0.01), fiber density (20.03%, P< 0.01) and had more less 6th-7th rib fat thickness (20.27%, P< 0.05), tendernce (17.32%, P< 0.05), and had more thick shoulder fat thickness (7.97%, P< 0.05), and had bigger the loin eye area (22.58%, P< 0.01) and fiber cross-sectional area (32.70%, P< 0.01) and fiber diameter (15.38%, P< 0.01) and lean meat (2.18%, P< 0.01) than the boars inherited from parental G allele. The results were suggested that the parental A allele has highly significant genetic effects in improving pig body development and carcass lean percent by increasing fiber diameter and the loin eye area, and decreasing the skin thickness and fat percent.