Coulthart Michael B, Posada David, Crandall Keith A, Dekaban Gregory A
Host Genetics and Prion Diseases Program, National Microbiology Laboratory, Health Canada, Winnipeg, MB, Canada R3E 3R2.
Infect Genet Evol. 2006 Mar;6(2):91-6. doi: 10.1016/j.meegid.2005.02.001. Epub 2005 Mar 23.
Recently, the putative finding of ancient human T cell leukemia virus type 1 (HTLV-1) long terminal repeat (LTR) DNA sequences in association with a 1500-year-old Chilean mummy has stirred vigorous debate. The debate is based partly on the inherent uncertainties associated with phylogenetic reconstruction when only short sequences of closely related genotypes are available. However, a full analysis of what phylogenetic information is present in the mummy data has not previously been published, leaving open the question of what precisely is the range of admissible interpretation. To fulfill this need, we re-analyzed the mummy data in a new way. We first performed phylogenetic analysis of 188 published LTR DNA sequences from extant strains belonging to the HTLV-1 Cosmopolitan clade, using the method of statistical parsimony which is designed both to optimize phylogenetic resolution among sequences with little evolutionary divergence, and to permit precise mapping of individual sequence mutations onto branches of a divergence network. We then deduced possible phylogenetic positions for the two main categories of published Chilean mummy sequences, based on their published 157-nucleotide LTR sequences. The possible phylogenetic placements for one of the mummy sequence categories are consistent with a modern origin. However, one of these placements for the other mummy sequence category falls very close to the root of the Cosmopolitan clade, consistent with an ancient origin for both this mummy sequence and the Cosmopolitan clade.
最近，在一具1500年前的智利木乃伊中发现了疑似古代人类1型嗜T细胞淋巴瘤病毒（HTLV-1）长末端重复序列（LTR）DNA，这引发了激烈的争论。这场争论部分基于当只有密切相关基因型的短序列可用时，系统发育重建所固有的不确定性。然而，此前尚未发表对木乃伊数据中存在的系统发育信息的全面分析，这使得究竟什么是可接受解释的范围这一问题悬而未决。为满足这一需求，我们以一种新的方式重新分析了木乃伊数据。我们首先使用统计简约法对来自HTLV-1世界范围进化枝现存毒株的188个已发表的LTR DNA序列进行系统发育分析，该方法旨在优化进化差异较小的序列之间的系统发育分辨率，并允许将单个序列突变精确映射到分歧网络的分支上。然后，我们根据已发表的157个核苷酸的LTR序列，推断出已发表的智利木乃伊序列的两个主要类别可能的系统发育位置。其中一类木乃伊序列可能的系统发育位置与现代起源一致。然而，另一类木乃伊序列的其中一个位置非常接近世界范围进化枝的根部，这与该木乃伊序列和世界范围进化枝的古老起源一致。
