Chinese alligator (Alligator sinensis) is an endemic species in China. The likely extinction of it in the wild has been recognised. To prevent this species becoming extinct, the Anhui Research Centre of Chinese Alligator Reproduction (ARCCAR) was established in Xuanzhou, Anhui Province in 1979, where has been established the largest captive population of Chinese alligator (XZSP) in the world. Another farm (CXSP) was established by villagers in Changxin, Zhejiang Province. The results of an investigation of the two captive subpopulation structures by genetic analysis are presented in this paper. We examined the genetic variation in the two captive subpopulations using RAPDs. Thirty-one random primers were selected among 199 random primers screened. A total of 193 reproducible RAPD fragments were scored among 43 individuals, of which 21 (10.88%) were polymorphic. The genetic distances between 43 individuals ranged from 0 to 0.0376 with average of 0.0104 0.0055 S. E. The genetic similarity in CXSP (0.9948 0.0029 S. E.) was higher than that in XZSP (0.9894 0.0055 S.E.). The founder effect is a possible explanation for very low genetic variation in CXSP. Analysis of the RAPD data showed that the mean phenotypic band frequencies of each polymorphic loci was 0.6656 0.3730 S. E. The lowest phenotypic band frequency (0.0233) was found in four of those polymorphic loci. There was no genetic difference between the two subpopulations (Dij=0.0009). According to the dendrogram and the distribution of polymorphic fragments in two subpopulations, CXSP originated genetically from XZSP. This paper summarises a preliminary research on genetic structure in populations of Chinese alligator. Although there is higher genetic similary (0.9896 0.0055 S. E.) in captive population of A. sinensis, we did not determine whether or not loss of genetic variation had occurred in relation to a wild control population. The data of malformed offspring will be collected carefully, and wild samples be added to set up a control population in future study.

The 16746-neucleotide (nt) sequence of mitochondrial DNA (mtDNA) of Chinese alligator, Alligator sinensis, was determined using the Long-PCR and primer walking methods. As is typical in vertebrates, the mtDNA encodes 13 proteins, 2 rRNA, 22 tRNA genes, and a noncoding control region. The composition of bases is respectively 29.43% A, 24.59% T, 14.86% G, 31.12% C. The gene arrangement differs from the common vertebrate gene arrangement, but is similar to that of other crocodiles. DNA sequence data from 12S rRNA, 16S rRNA, protein-coding genes and combined sequence data were used to reconstruct the phylogeny of reptiles with the MP and MLmethods. With this large data set and an appropriate range of outgroup taxa, the authors demonstrate that Chinese alligator is most closely related to American alligator among three crocodilian species, which suppors the traditional viewpoint. According to the branch lengths of ML tree from the combined data set, the primary divergence between Alligator and Caiman genus was dated at about 74.9 Ma, the split between Chinese alligator and American alligator was dated at 50.9 Ma.

With the commercial farming and exploitation of Chinese alligators (Alligator sinensis), illegal and inappropriately labeled Chinese alligator meat has appeared in markets. To prevent the illegal hunting and commerce for Chinese alligators, it will be important to develop an expedient and practical method for the identification of Chinese alligator meat. In this study, a pair of the species-specific PCR primers (Alli-M and Alli-R) was designed using sequence variations of mitochondrial DNA (mtDNA) cytochrome b gene between Chinese alligators and other crocodilians. By the multiplex PCR of using the species-specific primers and 12S rRNA universal primers L1091 and H1478, 31 samples (27 meat samples, 4 skin samples) were identified. The result of amplification displayed that only the fresh and the cooked meat samples from the Chinese alligator could be amplified with two bands. We also present a case of identification of a crocodilian body part found in a local market using the newly developed primers. The specific primers designed in this study could be widely used for the rapid and accurate identification of not only alligator meat but also other commercial products from Chinese alligator.

AIM: To clarify the types, regional distributions and distribution densities as well as morphological features of gastrointestinal (GI) endocrine cells in various parts of the gastrointestinal track (GIT) of four reptiles, Gekko japonicus, Eumeces chinensis, Sphenomorphus indicus and Eumeces elegans. METHODS: Paraffin-embedded sections (5μm) of seven parts (cardia, fundus, pylorus, duodenum, jejunum, ileum, rectum) of GIT dissected from the four reptiles were prepared. GI endocrine cells were revealed by using immunohistochemical techniques of streptavidin-peroxidase (S-P) method. Seven types of antisera against 5-hydroxytryptamine (5-HT), somatostatin (SS), gastrin (GAS), glucagon (GLU), substance P (SP), insulin and pancreatic polypeptide were identified and then GI endocrine cells were photomicrographed and counted. RESULTS: The GI endocrine system of four reptiles was a complex structure containing many endocrine cell types similar in morphology to those found in higher vertebrates. Five types of GI endocrine cells, namely 5-HT, SS, GAS, SP and GLU immunoreactive (IR) cells were identified in the GIT of G. japonicus, E. chinensis and S. indicus; while in the GIT of E. elegans only the former three types of endocrine cells were observed. No PP- and INS- IR cells were found in all four reptiles. 5-HT-IR cells, which were most commonly found in the pylorus or duodenum, distributed throughout the whole GIT of four reptiles. However, their distribution patterns varied from each other. SS-IR cells, which were mainly found in the stomach especially in the pylorus and/or fundus, were demonstrated in the whole GIT of E. chinensis, only showed restricted distribution in the other three species. GAS-IR cells, with a much restricted distribution, were mainly demonstrated in the pylorus and/or the proximal small intestine of four reptiles. GLU-IR cells exhibited a limited and species-dependent variant distribution in the GIT of four reptiles. SP-IR cells were found throughout the GIT except for jejunum in E. elegans and showed a restricted distribution in the GIT of G. japonicus and S. indicus. In the GIT of four reptiles the region with the highest degree of cell type heterogeneity was pylorus and most types of GI endocrine cells along the GIT showed the peak density in pylorus as well. CONCLUSION: Some common and unique features of the distribution and morphology of different types of GI endocrine cells are found in four reptiles. This common trait may reflect the similarity in digestive physiology of various vertebrates.

To distinguish sika deer (Cervus nippon) tissue samples from those of sympatric cervids in the southern part of Anhui Province, China, we analysed randomly amplified polymorphic DNA (RAPD) fragments of 12 individual samples from four cervid species: black muntjac (Muntiacus crinifrons), Reeve’s muntjac (Muntiacus reevesi), sika deer (Cervus nippon), and tufted deer (Elaphodus cephalophus). Only one primer among the 100 screened produced a clear specific band for identifying DNA of sika deer. We cloned and sequenced 449 bp from this fragment of DNA. We then designed a pair of 18 bp primers (MHL-U/MHL-D) according to the sequence, resulting in a 251 bp sequence-characterised amplified region (SCAR) for sika deer. By combining this pair of SCAR primers with a universal set of mammalian DNA primers, the identification of sika deer tissue samples by a simple common multiplex PCR assay is straightforward, rapid, and reliable. The method will be useful for cervid conservation and cervid bushmeat trade regulation.

Regression analysis between body and head measurements of Chinese alligators (Alligator sinensis) in the captive population.— Four body–size and fourteen head–size measurements were taken from each Chinese alligator (Alligator sinensis) according to the measurements adapted from Verdade. Regression equations between body–size and head–size variables were presented to predict body size from head dimension. The coefficients of determination of captive animals concerning body–and head–size variables can be considered extremely high, which means most of the head–size variables studied can be useful for predicting body length. The result of multivariate allometric analysis indicated that the head elongates as in most other species of crocodilians. The allometric coefficients of snout length (SL) and lower ramus (LM) were greater than those of other variables of head, which was considered to be possibly correlated to fights and prey. On the contrary, allometric coefficients for the variables of obita (OW, OL) and postorbital cranial roof (LCR), were lower than those of other variables.

通过酶切、克隆、测序、结合Long-PCR和PrimerWalking法对扬子鳄线粒体DNA基因组进行全序列测定，结果表明，扬子鳄线粒体基因组DNA序列全长为16746bp，其基因组碱基组成为29.43%A，24.59%T，14.86%G，31.12%C.与其他大多数脊椎动物相同，其基因组由13个蛋白质编码基因、2个rRNA基因、22个tRNA基因及1个非编码的控制区（D-loop）组成，基因的排列与已测序的鳄类相似在全序列分析的基础上，对12SrRNA基因序列、16SrRNA基因序列、蛋白质编码基因序列及其合并数据用MP法和ML法构建系统发生树，结果表明扬子鳄与密河鳄的亲缘关系较近，支持传统观点根据树的支长数值估计钝吻鳄属发生的时间为74.9MaBP，扬子鳄与密河鳄分歧的时间为50.9MaBP.

运用一种改进的提取方法，作者从鞣制皮革中成功地提取了总DNA，同时还对尾尖皮、鳞片、盐腌生皮等皮质进行了DNA提取;用12SrRNA基因扩增的通用引物、扬子鳄鉴别引物、微卫星引物及RAPD引物进行PCR扩增，并对部分扩增结果进行测序，以检验提取效果。结果证明，几种皮质标本都可提取出DNA，其中尾尖皮和鳞片的提取效果较好，用四种引物都可扩增出明显亮带;盐腌生皮和鞣制皮提取结果也很好，并且用12SrRNA通用引物、扬子鳄鉴别引物扩增的亮带较明显，可进行扬子鳄皮质用品等的分子鉴定及部分序列的扩增和测序研究[动物学报50（2）：297-301，2004]。

3头扬子鳄血样取自宣城安徽省扬子鳄繁殖研究中心。利用一对简并引物对MHCⅡ类B基因第二外元的部分片段进行扩增;通过克隆、单链构象多态性分析、测序，并将测得序列与下载的8个物种MHC序列比对，确定序列差异和变异位点;利用MEGA软件构建NJ树，PAUP4.0构建MP树。结果得到10种不同的序列，片段长166bp。核苷酸序列中有38个变异位点，氨基酸序列中有23个变异位点;推定的抗原结合位点非同义替换（dN）明显高于同义替换（dS）。10种序列的NJ树和MP树极为相似，均为A、B两个分支，两个分支明显的特异性位点核苷酸序列中有9个，氨基酸序列中有7个。表明扬子鳄MHCⅡ类B基因第二外元有较高的多态性，有利于扬子鳄饲养种群的遗传保护。

作者分别于2002和2003年抽样调查了安徽省扬子鳄国家级自然保护区有或曾经有野生扬子鳄（Alligatorsinensis）分布的22个样地，选择了与野生扬子鳄生存有关的8类生态因子，即水域中岛屿情况、水域水面的稳定度、水体pH值、螺类丰富度、岸线植被盖度、岸线土壤质地、苦竹密度和植被类型，运用资源选择函数结合主成分分析方法研究了野生扬子鳄对生境的选择。结果表明岸线植被盖度对野生扬子鳄的生境选择影响最大，其次是水体pH值，再次是螺类丰富度、苦竹密度、水域水面的稳定度和土壤质地;而水域中岛屿情况与植被类型对野生扬子鳄生境选择的影响则较弱。