Although two species of bottlenose dolphins (Tursiops spp.) in Chinese waters have been recognized, their pattern of genetic variation is unclear at present. In the present study, 424-bp of the mitochondrial control region from 30 bottlenose dolphins collected in Chinese waters were sequenced. Fortyseven variable sites were identified from these sequences, and 9 and 11 haplotypes were defined respectively for truncatus-and aduncus-type, two morphotypes previously recognized for bottlenose dolphins in Chinese waters. These haplotypes were combined with published mitochondrial control region sequences of other bottlenose dolphins from Chinese, Indonesian, Australian, and Atlantic waters etc. Sequence variability comparison and phylogenetic reconstruction using neighbor joining (NJ) and maximum likelihood (ML) algorithms exclusively supported the separation of haplotypes into two monophyletic clades, each of which corresponds to truncatus-and aduncus-type. This provided strong support to separate the two morphotypes into respective species, T. truncatus and T. aduncus. No shared haplotype was found between Tursiops species, and four fixed diagnostic site differences between them were identified. All samples from the northern part of Chinese waters, i. e. the Yellow Sea and the northern East China Sea, were genetically identified as T. truncatus exclusively, whereas most samples from the southern part of Chinese Waters, i.e. the southern part of the East China Sea, the Taiwan Straits, the South Chinese Sea, and the Gulf of Beibuwan, were identified as T. aduncus, but with both species overlapping in the Taiwan Strait. This genetic pattern was congruent with the distribution pattern of Tursiops as previously revealed by morphological and ecological evidences. Although the distribution of the two species overlapped in the Taiwan Strait (and maybe adjacent waters), there was no evidence of genetic interchange between them, indicating reproductive isolation. The present study strongly argues for treating the two bottlenose dolphin morphotypes/species as separate management units in making up conservation measures, but further study on the intraspecific structure using multiple molecular marker is also urgent for effective conservation.

To help resolve phylogenetic relationships among the mitten crabs, complete sequences of the nuclear DNA internal transcribed spacer (ITS) and portions of the mitochondrial genome corresponding to the cytochrome oxidase I (COI), were sequenced for all Asian mitten crabs of the genus Eriocheir and seven species of the Grapsoidea. The resulting phylogeny supports the establishment of a separate genus Neoeriocheir, but does not provide justification for the recognition of Platyeriocheir. A female mitten crab specimen from the Zhujiang River, China, was considered to be Eriocheir recta (Stimpson, 1858), a species previously synonymized with Eriocheir japonica (de Haan, 1835). In the ITS analysis, a sequence from Eriocheir formosa (from Taiwan) falls within a wellsupported E. recta group, which indicates that E. formosa may have to be synonymized with E. recta. Three previously recognized members of the genus, E. japonica, Eriocheir sinensis, and Eriocheir hepuensis constitute a monophyletic sister group to E. recta in all phylogenetic trees. We provide evidence for the conspecific status of these taxa. Phylogenetic trees based on COI and combined COI and ITS sequences indicate that E. japonica consists of three subgroups. Since the name E. japonica (de Haan, 1835) takes precedence over E. sinensis (H. Milne Edwards, 1853) and E. hepuensis Dai, 1991, we suggest that these three subgroups correspond to three subspecies of E. japonica: E. j. japonica, E. j. sinensis, and E. j. hepuensis.

综述了近年来分子生物学标记技术在鲸类系统学研究中的进展。分子生物学证据支持鲸目与有蹄类之间有较近的亲缘关系，并支持鲸类的单系起源，但鲸类不同类群（须鲸类、抹香鲸类及不包括抹香鲸类的齿鲸类）之间的系统发生关系仍存在争议。抹香鲸类到底与须鲸类还是与其它齿鲸类有更近的亲缘关系，不同的分子生物学家所得到的结果并不一致。此外，分子生物学技术还被用于解决须鲸亚目和齿鲸亚目内科间以及科内种间的系统发生关系，特别是齿鲸亚目的海豚科、鼠豚科和淡水豚类。通过分子标记技术来研究鲸类种下的遗传结构是鲸类分子系统学研究中的一个新热点，使用的标记主要是mtDNA控制区、核DNA微卫星和主要组织相容性复合体（major histo. compatibility complex, MHC）等。

测定了45个克隆的白紧豚（Lipotes zexilifer）MHCⅡ类基因DQB座位第二外元172bp的核苷酸序列，共获得15种序列，发现了22个变异位点。核苷酸的非同义替换明显多于同义替换，并造成了15个氨基酸的改变。氨基酸的替换趋于集中在假定的与抗原的选择性识别相关的位点附近。白鱀豚DQB基因的核苷酸和氨基酸序列与文献报道的白鲸（Delphinapterus leutcas）和一角鲸（Moncdon monoceroS）DQBl序列具有较高的同源性。氨基酸序列不具备人及其它一些灵长类动物DQB2基因所共有的基序（Motif），而与牛DQBl基因的基序相近，说明本研究得到的白紧豚MHC序列应属于类DQBl基因。同一个体出现了多种序列的情况，提示白鱀豚的DQB基因可能存在着座位重复。白鱀豚的类DQBl座位的序列中存在多种基序的不同组合，推测是由于基因转换造成的。

真海豚包括长喙真海豚和短喙真海豚2种，而中国水域的真海豚到底是哪一个种或是否同时有两个种的存在，并不清楚。本研究测定了12头中国水域真海豚mtDNA控制区366bp和细胞色素b（cytochInrnfIb，cyt 6）基因336 bp的序列，并与已发表的其它真海豚的序列合并分析，初步鉴定中国水域真海豚的分类地位。结果表明，中国水域的真海豚与东太平洋的长喙真海豚有相同的鉴别位点，且两者之间的核苷酸歧异度（控制区：1.93±0.22%，cyt 6基因：0.68±0.19%）显著低于与短喙真海豚之间的差异（控制区：2.92±0.41%，cyt 6基因：0.95±0.27%）。通过MJGA （rnokcular evolutionary genetic analysis）软件中的邻接法进行的系统发生分析中，中国水域的真海豚与长喙真海豚聚成一支，有明显较近的亲缘关系。因此，中国水域的真海豚在分类上应归属于长喙真海豚。