Orlando Ludovic, Calvignac Sébastien, Schnebelen Céline, Douady Christophe J, Godfrey Laurie R, Hänni Catherine
Université de Lyon, Institut de Génomique Fonctionnelle de Lyon, Institut Fédératif Biosciences Gerland Lyon Sud, Université Lyon 1, CNRS, INRA, Ecole Normale Supérieure de Lyon, 69364 Lyon Cédex 07, France.
BMC Evol Biol. 2008 Apr 28;8:121. doi: 10.1186/1471-2148-8-121.
Although today 15% of living primates are endemic to Madagascar, their diversity was even greater in the recent past since dozens of extinct species have been recovered from Holocene excavation sites. Among them were the so-called "giant lemurs" some of which weighed up to 160 kg. Although extensively studied, the phylogenetic relationships between extinct and extant lemurs are still difficult to decipher, mainly due to morphological specializations that reflect ecology more than phylogeny, resulting in rampant homoplasy.
Ancient DNA recovered from subfossils recently supported a sister relationship between giant "sloth" lemurs and extant indriids and helped to revise the phylogenetic position of Megaladapis edwardsi among lemuriformes, but several taxa - such as the Archaeolemuridae - still await analysis. We therefore used ancient DNA technology to address the phylogenetic status of the two archaeolemurid genera (Archaeolemur and Hadropithecus). Despite poor DNA preservation conditions in subtropical environments, we managed to recover 94- to 539-bp sequences for two mitochondrial genes among 5 subfossil samples.
This new sequence information provides evidence for the proximity of Archaeolemur and Hadropithecus to extant indriids, in agreement with earlier assessments of their taxonomic status (Primates, Indrioidea) and in contrast to recent suggestions of a closer relationship to the Lemuridae made on the basis of analyses of dental developmental and postcranial characters. These data provide new insights into the evolution of the locomotor apparatus among lemurids and indriids.
尽管如今15%的现存灵长类动物是马达加斯加特有的,但由于从全新世挖掘地点发现了数十种已灭绝物种,它们在近代的多样性更为丰富。其中包括所谓的“巨型狐猴”,有些体重可达160千克。尽管对其进行了广泛研究,但已灭绝狐猴和现存狐猴之间的系统发育关系仍难以解读,主要是因为形态特化更多地反映了生态而非系统发育,导致普遍存在同形现象。
从亚化石中提取的古代DNA最近支持了巨型“树懒”狐猴与现存大狐猴科之间的姐妹关系,并有助于修正爱德华巨狐猴在狐猴目中的系统发育位置,但仍有几个类群——如古狐猴科——有待分析。因此,我们利用古代DNA技术来确定两个古狐猴科属(古狐猴属和恐狐属)的系统发育地位。尽管亚热带环境中DNA保存条件不佳,我们仍成功从5个亚化石样本中获得了两个线粒体基因的94至539个碱基对的序列。
这些新的序列信息为古狐猴属和恐狐属与现存大狐猴科亲缘关系较近提供了证据,这与它们分类地位(灵长目,大狐猴超科)的早期评估一致,与最近基于牙齿发育和颅后特征分析提出的与狐猴科关系更密切的观点相反。这些数据为狐猴科和大狐猴科运动器官的进化提供了新的见解。