Müller Stefan, Hollatz Melanie, Wienberg Johannes
Institut für Anthropologie und Humangenetik, Department Biologie II, Ludwig-Maximilians-Universität, Richard-Wagner-Strasse 10, 80333 Munich, Germany.
Hum Genet. 2003 Nov;113(6):493-501. doi: 10.1007/s00439-003-0997-2. Epub 2003 Sep 3.
Although human and gibbons are classified in the same primate superfamily (Hominoidae), their karyotypes differ by extensive chromosome reshuffling. To date, there is still limited understanding of the events that shaped extant gibbon karyotypes. Further, the phylogeny and evolution of the twelve or more extant gibbon species (lesser apes, Hylobatidae) is poorly understood, and conflicting phylogenies have been published. We present a comprehensive analysis of gibbon chromosome rearrangements and a phylogenetic reconstruction of the four recognized subgenera based on molecular cytogenetics data. We have used two different approaches to interpret our data: (1) a cladistic reconstruction based on the identification of ancestral versus derived chromosome forms observed in extant gibbon species; (2) an approach in which adjacent homologous segments that have been changed by translocations and intra-chromosomal rearrangements are treated as discrete characters in a parsimony analysis (PAUP). The orangutan serves as an "outgroup", since it has a karyotype that is supposed to be most similar to the ancestral form of all humans and apes. Both approaches place the subgenus Bunopithecus as the most basal group of the Hylobatidae, followed by Hylobates, with Symphalangus and Nomascus as the last to diverge. Since most chromosome rearrangements observed in gibbons are either ancestral to all four subgenera or specific for individual species and only a few common derived rearrangements at subsequent branching points have been recorded, all extant gibbons may have diverged within relatively short evolutionary time. In general, chromosomal rearrangements produce changes that should be considered as unique landmarks at the divergence nodes. Thus, molecular cytogenetics could be an important tool to elucidate phylogenies in other species in which speciation may have occurred over very short evolutionary time with not enough genetic (DNA sequence) and other biological divergence to be picked up.
尽管人类和长臂猿被归类于同一灵长类超科（人猿总科），但它们的核型因广泛的染色体重排而有所不同。迄今为止，对于塑造现存长臂猿核型的事件仍了解有限。此外，对于十二种或更多现存长臂猿物种（小猿，长臂猿科）的系统发育和进化了解甚少，并且已发表了相互矛盾的系统发育树。我们基于分子细胞遗传学数据，对长臂猿染色体重排进行了全面分析，并对四个公认的亚属进行了系统发育重建。我们使用了两种不同的方法来解释我们的数据：（1）基于在现存长臂猿物种中观察到的祖先与衍生染色体形式的识别进行分支系统发育重建；（2）一种方法是，将因易位和染色体内重排而发生变化的相邻同源片段在简约分析（PAUP）中视为离散性状。猩猩作为“外类群”，因为它的核型被认为与所有人类和猿类的祖先形式最为相似。两种方法都将白眉长臂猿亚属置于长臂猿科最基部的类群，其次是长臂猿属，合趾猿属和黑冠长臂猿属最后分化。由于在长臂猿中观察到的大多数染色体重排要么是所有四个亚属共有的祖先特征，要么是个别物种特有的，并且仅记录了在随后分支点处的少数共同衍生重排，所有现存长臂猿可能在相对较短的进化时间内发生了分化。一般来说，染色体重排产生的变化应被视为分歧节点处的独特标志。因此，分子细胞遗传学可能是阐明其他物种系统发育的重要工具，在这些物种中，物种形成可能发生在非常短的进化时间内，没有足够的遗传（DNA序列）和其他生物学差异可供识别。
