朱鹮线粒体DNA的分子系统发育

朱Huan是一种濒危鸟类。过度开发和栖息地的破坏导致了朱Huan日本种群的绝灭，而在中国目前也仅存一野生种群。本文利用NJ法和最大简约法分析了鹳形目鸟类977bp的线粒体DNA细胞色素b基因的部分序列，以期从DNA水平上阐明朱Huan的系统地位。结果表明，朱Huan与彩Huan和非洲琶鹭组成一姐妹群；NJ法分析得出的结果与DNA杂交分析结果一致，即((Huan科，鹭科)，鹳科)；而最大简约法分析的结果则与形态学结果一致，即((鹭科，鹳科)，Huan科)。同时，这两种系统树上较低的置信度，认为部分是由于可用细胞色素b基因序列的有限所致。

MOLECULAR PHYLOGENY OF CRESTED IBIS, NIPPONIA NIPPON,INFERRED FROM MITOCHONDRIAL CYTOCHROME-B GENE SEQUENCE

The Crested Ibis Nipponia nippon is one of the critically endangered species. Overexploitation and destruction ofhabitat led the Japanese population to extinction during the 20 th century. Only one wild population and two captive popula-tions are in China at present. Little is known about the molecular phylogeny of this species at the level of gene sequence, 977bpof the mitochondrial cytochrome-b gene was analyzed to clarify the phylogenetic status of N. nippon among the order Ciconi-iformes using NJ and parsimony analysis in the present study. Our results showed that N. nippon became a sister group to acluster of P. falcinellus and P. alba based on molecular analysis which were not congruent with the traditional classification.The branching pattern was ((Threskiornithidae, Ardeidae), Ciconiidae) in the NJ tree which was congruent with the phyloge-netic relationship inferred from DNA hybridization analysis. On the other hand, the brancing order in the parsimony tree was( (Ardeidae, Ciconiidae), Threskiornithidae) which was in agreement with the taxonomy based on the morphological analysis.Neither of the branching patterns in the trees was supported with high bootstrap values in our analysis. This is partly becausethe number of available cytochrome b gene sequences is limited for those families.