National Engineering Laboratory for Animal Breeding, Department of Animal Breeding and Genetics, China Agricultural University, 100193, Beijing, P. R. China.
Poult Sci. 2011 Apr;90(4):759-65. doi: 10.3382/ps.2010-01133.
Avian leukosis virus (ALV) subgroup E (ALVE) is an endogenous retrovirus in the chicken genome. The chickens carrying ALVE locus 3 (ALVE3), 6 (ALVE6), 9 (ALVE9), and 21 (ALVE21) have been proved to be susceptible to ALV. Tumor virus locus B (TVB) encodes the cellular receptor for ALV subgroups B, D, and E. The insertions of the 4 ALVE loci and the genotypes of TVB have not been demonstrated in Chinese indigenous chicken breeds. In the present study, the existence of ALVE3, ALVE6, ALVE9, and ALVE21 were detected in 10 native breeds of Chinese chickens and an introduced breed, the White Leghorn (2 populations in this study, WL1 and WL2), by locus-specific PCR. The PCR products of ALVE were further confirmed by sequencing assay. We also surveyed the status of genotypes of TVB in Silkie, Beijing You, and White Leghorn (WL1 and WL2) chickens with pyrosequencing assays. The results showed that the carrier frequency of ALVE3 was 1.3% in the Chinese chicken population, and was 10.3 in WL1 and 49.2% in WL2. The carrier frequency of ALVE6 was 5.4% in native breeds of Chinese birds, in contrast with 0% in WL1 and 6.8% in WL2. The carrier frequency of ALVE9 was 0.1% in the Chinese indigenous population, and was 16.0% in WL1 and 11.9% in WL2. The carrier frequency of ALVE21 was 10.4% in Chinese chickens, whereas ALVE21 was detected with a frequency of 0% in WL1 and 50% in WL2. The frequency of the TVB resistance allele (TVBR and TVBR') was 0.4% in Beijing You chickens, whereas it was 70.5% in WL1 and 54.5% in WL2. No carriers of ALVE3, ALVE9, and ALVE21 were detected in Silkie fowl, a famous Chinese native breed that has been used as a source for alternative medicine. These results present molecular evidence of ALVE3, ALVE6, ALVE9, and ALVE21 insertions and TVB genotypes in Chinese indigenous chickens and could provide potential molecular insights into anti-ALV breeding in chickens.
禽白血病病毒（ALV）亚群 E（ALVE）是鸡基因组中的内源性逆转录病毒。携带 ALVE 位点 3（ALVE3）、6（ALVE6）、9（ALVE9）和 21（ALVE21）的鸡已被证明易感染 ALV。肿瘤病毒 B 位（TVB）编码 ALV 亚群 B、D 和 E 的细胞受体。在中国地方鸡种中尚未证明这 4 个 ALVE 位点的插入和 TVB 的基因型。在本研究中，通过特异性 PCR 检测了 10 个中国本地鸡种和一个引进品种（白来航鸡的 2 个种群，WL1 和 WL2）中的 ALVE3、ALVE6、ALVE9 和 ALVE21 的存在。PCR 产物进一步通过测序实验确认。我们还通过焦磷酸测序检测了丝毛鸡、北京油鸡和白来航鸡（WL1 和 WL2）中 TVB 基因型的状态。结果表明，ALVE3 的携带频率在中国鸡群中为 1.3%，而在 WL1 中为 10.3%，在 WL2 中为 49.2%。ALVE6 在本地中国鸟类品种中的携带频率为 5.4%，而在 WL1 中为 0%，在 WL2 中为 6.8%。ALVE9 在本地中国种群中的携带频率为 0.1%，而在 WL1 中为 16.0%，在 WL2 中为 11.9%。ALVE21 在本地中国鸡中的携带频率为 10.4%，而在 WL1 中为 0%，在 WL2 中为 50%。在著名的中国地方鸡种丝毛鸡中未检测到 ALVE3、ALVE9 和 ALVE21 的携带，而在白来航鸡中，TVB 抗性等位基因（TVBR 和 TVBR'）的频率为 0.4%，在 WL1 中为 70.5%，在 WL2 中为 54.5%。在作为替代医学来源的著名中国地方鸡种丝毛鸡中，未检测到 ALVE3、ALVE9 和 ALVE21 的携带。这些结果提供了中国本地鸡中 ALVE3、ALVE6、ALVE9 和 ALVE21 插入和 TVB 基因型的分子证据，并为鸡的抗 ALV 育种提供了潜在的分子见解。
