Cong Yingying, Zarlenga Dante S, Richt Juergen A, Wang Xin, Wang Yang, Suo Siqingaowa, Wang Jingfei, Ren Yudong, Ren Xiaofeng
College of Veterinary Medicine, Northeast Agricultural University, 59 Mucai Street, Xiangfang District, Harbin 150030, China.
Virus Genes. 2013 Aug;47(1):66-74. doi: 10.1007/s11262-013-0926-y. Epub 2013 Jun 9.
The objective of the present study was to gain new insights into the evolution, homologous recombination, and selection pressures imposed on the porcine torovirus (PToV), by examining the changes in the hemagglutinin-esterase (HE) gene. The most recent common ancestor of PToV was estimated to have emerged 62 years ago based upon HE gene sequence data obtained from PToV isolates originating from Spain, South Korea, Netherlands, Hungary, and Italy and using the HE gene of Bovine torovirus isolates Niigata1 (AB661456) and Niigata3 (AB661458) as outgroups. The HE gene sequence data segregated all the PToV isolates into two well-supported monophyletic groups; however, various isolates from Spain, Italy, and South Korea did not segregate geographically suggesting very recent translocation of the viruses to these localities. Evidence of recombination was observed between two South Korean isolates that partitioned into two distinct subclades. Data further suggest that most of the nucleotides in the HE gene are under negative selection; however, changes within codon 237 showed an evidence of positive selection.
本研究的目的是通过研究血凝素酯酶（HE）基因的变化，深入了解猪环曲病毒（PToV）的进化、同源重组和选择压力。基于从西班牙、韩国、荷兰、匈牙利和意大利的PToV分离株获得的HE基因序列数据，并以牛环曲病毒分离株新潟1（AB661456）和新潟3（AB661458）的HE基因为外群，估计PToV的最近共同祖先出现在62年前。HE基因序列数据将所有PToV分离株分为两个得到充分支持的单系群；然而，来自西班牙、意大利和韩国的各种分离株在地理上并未分开，这表明这些病毒最近才转移到这些地区。在两个韩国分离株之间观察到重组证据，这两个分离株分为两个不同的亚分支。数据进一步表明，HE基因中的大多数核苷酸处于负选择之下；然而，密码子237内的变化显示出正选择的证据。
