Retroviralenvelope (env)-like sequences in 2 cultivated allotetraploid cottons and their diploid progenitors have been identified and characterized in this study. DNA sequence analysis reveals that these sequences are heterogeneous. The observed sequence diversity, however, seems to preserve coding information. This is evidenced by the detection of the transmembrane domain (TM), which is the most conserved feature of the divergent retroviral env genes. The high ratio of synonymous to nonsynonymous changes suggests that these sequences are evolving under purifying selection. Phylogenetic analysis shows thatGossypium sequences closely cluster with a lineage of plant endogenous retroviruses that have anenv-like gene. These results provide evidence for the antiquity and the wide diversity ofenv-like sequences in theGossypium genome.

中文翻译：

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栽培异源四倍体棉属物种及其二倍体祖细胞中包膜样结构域的序列异质性。

在这项研究中已经鉴定并表征了 2 个栽培异源四倍体棉花及其二倍体祖细胞中的逆转录病毒包膜( env ) 样序列。DNA 序列分析表明这些序列是异质的。然而，观察到的序列多样性似乎保留了编码信息。跨膜结构域 (TM) 的检测证明了这一点，这是不同逆转录病毒 env 基因最保守的特征。同义与非同义变化的高比率表明这些序列正在纯化选择下进化。系统发育分析表明，棉属序列与具有env的植物内源性逆转录病毒谱系紧密聚类- 基因。这些结果为Gossypium基因组中env样序列的古老性和广泛多样性提供了证据。