Smith E J, Levin I
U.S. Department of Agriculture, Avian Disease and Oncology Laboratory, East Lansing, Michigan 48823.
Poult Sci. 1991 Sep;70(9):1957-64. doi: 10.3382/ps.0701957.
To investigate further the sex-linked, slow-feathering (SF) locus, a DNA hybridization probe that flanks the integration site of endogenous virus ev21 was used to probe Southern blots from a variety of commercial SF White Leghorn (WL), broiler, and endangered lines. After HaeIII digestion of DNA from SF WL, the 5' and 3' provirus-cell junction fragments were seen in addition to a 2.5-kb fragment of cell sequences that was homologous with the viral integration region. The latter polymorphism, which appeared to represent sequences duplicated after integration of EV21, was designated unoccupied repeat URa. Among SF broiler crosses, the same provirus-cell junction fragments were found but the pristine region that represented the 1.6-kb proviral URb was also found. Only URb was found among rapid-feathering (RF) chickens, regardless of breed. Although there was marked (greater than 95%), agreement between the presence of ev21-cell; junction fragments and the SF phenotype among both WL and broilers, Southern blots of DNA from a few commercial SF broiler chickens lacked ev21 junction fragments but some RF revertants harbored ev21 junction fragments. These anomalies suggest that ev21 may not be the sole determinant of the SF phenotype.
为了进一步研究性连锁慢羽（SF）位点，使用了一种位于内源性病毒ev21整合位点侧翼的DNA杂交探针，对来自各种商业性SF白来航鸡（WL）、肉鸡和濒危品系的Southern印迹进行探测。用HaeIII消化SF WL的DNA后，除了一个与病毒整合区域同源的2.5kb细胞序列片段外，还可见到5'和3'前病毒-细胞连接片段。后一种多态性似乎代表了EV21整合后重复的序列，被命名为空位重复序列URa。在SF肉鸡杂交后代中，发现了相同的前病毒-细胞连接片段，但也发现了代表1.6kb前病毒URb的原始区域。无论品种如何，快羽（RF）鸡中只发现了URb。尽管在WL和肉鸡中，ev21-细胞连接片段的存在与SF表型之间存在显著（大于95%）的一致性，但一些商业性SF肉鸡的DNA的Southern印迹缺乏ev21连接片段，而一些RF回复体则含有ev21连接片段。这些异常情况表明，ev21可能不是SF表型的唯一决定因素。
