Schmitz Jürgen, Ohme Martina, Suryobroto Bambang, Zischler Hans
Primate Genetics, German Primate Center, Kellnerweg 4, 37077 Göttingen, Germany.
Mol Biol Evol. 2002 Dec;19(12):2308-12. doi: 10.1093/oxfordjournals.molbev.a004054.
Although a general agreement on the major groups of eutherian orders and their phylogenetic affiliations is emerging, the evolutionary affiliations among the members constituting these groups are still subject to debate. A prominent example is the recently published molecular evidence that challenges the long assumed monophyly of primates, displaying the colugo or flying lemur (Cynocephalus, Dermoptera) as a sister to anthropoid primates (Arnason et al. 2002 ) and positioning them after the prosimian primates (tarsiers and strepsirhines) split off. The phylogenetic analysis of the complete mitochondrial (mt) genome sequence of Cynocephalus variegatus presented in this study first appears to corroborate interpretations of primates as a paraphyletic group. However, more detailed analyses disclosed that mt nucleotide composition and consequently amino acid (AA) composition varied considerably among the species analyzed. This led us to assume that the flying lemur may be incorrectly grouped with anthropoids on the basis of similar mt nucleotide and AA compositions, rather than reflecting the true evolutionary relationship. To reanalyze the flying lemur's evolutionary association with other eutherian orders from a completely different molecular perspective, a molecular cladistic approach was applied. To this end, we determined the presence/absence pattern of transposable elements that provide a nearly homoplasy-free and copious source of molecular evolutionary markers, with well-defined character polarity. We could identify transposable elements, both on a multilocus and single-locus level, being present in all extant primate infraorders but absent in the flying lemur, thus clearly supporting the monophyly of primates by retropositional evidence.
尽管在真兽类目及其系统发育关系的主要类群上已形成了普遍共识,但构成这些类群的成员之间的进化关系仍存在争议。一个突出的例子是最近发表的分子证据,该证据对长期以来假定的灵长类单系性提出了挑战,将猫猴或飞狐猴(鼯猴科,皮翼目)显示为类人猿灵长类的姐妹群(阿诺松等人,2002年),并将它们置于原猴亚目灵长类(跗猴和湿鼻灵长类)分化之后。本研究中对马来亚鼯猴完整线粒体(mt)基因组序列的系统发育分析最初似乎证实了灵长类是一个并系群的解释。然而,更详细的分析表明,在所分析的物种中,mt核苷酸组成以及因此的氨基酸(AA)组成差异很大。这使我们认为,飞狐猴可能是基于相似的mt核苷酸和AA组成而被错误地与类人猿归为一类,而不是反映了真正的进化关系。为了从完全不同的分子角度重新分析飞狐猴与其他真兽类目的进化关联,我们应用了分子分支系统学方法。为此,我们确定了转座元件的存在/缺失模式,这些转座元件提供了一个几乎无同塑性且丰富的分子进化标记来源,具有明确的性状极性。我们能够在多位点和单一位点水平上鉴定出转座元件,它们存在于所有现存的灵长类下目中,但在飞狐猴中不存在,因此通过反转录证据明确支持了灵长类的单系性。