贵州汉族、苗族、布依族和水族人群线粒体DNA多态性研究

用16种限制性内切酶对150个样本进行了mtDNA的限制性片段长度多态性(RFLP)分析。共检测到31种限制性格局, 其中Hae Ⅱ-13型、EcoRV-3型和PstⅠ-型3种限制性格局 为新报道。综合这些限制性格局, 共得出28种mtDNA类型。运用UPG法和简约法分析了各mtDNA类型之间、各人群之间的聚类关系。结果表明: 水族人群的mtDNA变异度较大; 汉族和苗族的亲缘关系最近, 布依族和水族有着较远的亲缘关系。图4表4参28

A molecular model of braid-like DNA structure

The three-dimensional molecular models of DNA triple helices and triple-stranded brain-like structure were built up by molecular architecture, and their structural features and energy decomposition were examined. The results showed: (i) The base triplet is the element forming braid-like and triple helix DNA; (ii) Under specified conditions, DNA could form the triplet-stranded braid-like structure; (iii) DNA stability of the braid-like structure is less than that of the triple helix structure. (C) 1995 Academic Press Limited.

Methylation and gene mutation in eukaryotic DNA

5-methylcytosine (m(5)C) as a rare base exists in eukaryotic genomes, which is a normal constitution in many eukaryotic DNA and the existence of m(5)C is a feature of eukaryotic DNA. Under regular physiological conditions, cytosine of eukaryotic DNA is usually methylated. Up to the present, many people consider that the m(5)C may be mutation hotspots by the deamination leading to gene mutation. Our study indicated that the spontaneous mutation caused by the transition of G.C --> A.T, in eukaryotic DNA, may result from the tautomer changing of base pairs and may also be cause by other factor actions, however it could not be caused by the deamination of m(5)C.

云南龙陵黄山羊线粒体DNA限制性酶切分析

采用碱性变性法提取来自于龙陵县不同地区的18只黄山羊个体的线粒体DNA(mtDNA),并用Apa I、Ava I、BamH I、Bcl I、Bgl I、Bgl II、Cla I、Dra I、EcoR I、EcoR V、Hae I、Hind III、Kpn I、Pst I、Pvu II、Sac I、Sal I、Sma I、Stu I和Xba I等20种限制性内切酶进行酶切分析。 结果发现龙陵黄山羊线粒体DNA的分子量大小约为15.8Kb;不同酶的酶切位点分别为:Dra I有7个酶切位点,Ava II有6个酶切位点,EcoR V和Stu I共有5个酶切位点,Hind III和Hea II有4个酶切位点,BamH I、Bgl II、Pst I和Pvu II有3个酶切位点,Apa I、Cla I有2个酶切位点,其余有1个酶切位点。

麂属动物陈旧皮张标本的DNA提取及PCR扩增

用改进的方法从保存于本单位标本中提取DNA, 所得DNA片段的分子量从100bp到1kb以上。利用线粒体DNA细胞色素b通用引物和PCR技术。从小麂、印度麂、贡山麂、费氏麂、黑麂DNA中扩增出307bp的 细胞色素b特异片段(加上两端引物后长度为364bp)。用28种限制性内切酶对 新鲜血样和从陈旧皮张标本中所得扩增片段进行酶切分析, 发现只有4个酶(DraⅠ、xbaⅠ、HaeⅢ、HpaⅡ)在这个片段上有切点, 其中HaeⅢ和HapⅡ的识别位点在各种麂中有所不同。 图3参10

Phylogeny of Muntiacus (Cervidae) based on mitochondrial DNA restriction maps

Mitochondrial DNA restriction maps for 12 restriction enzymes of four species of muntjacs-Indian muntjac (M. muntjak), Gongshan muntjac (M. gongshanensis), black muntjac (M. crinifrons), and Chinese muntjac (M. reevesi)-were compared to estimate the phylogenetic relationships among them. Phylogenetic trees were constructed by both distance and parsimony methods. The two resulting trees share a similar topology, which indicates that the black muntjac and the Gongshan muntjac are closely related, followed by the Chinese muntjac; the Indian muntjac is the sister taxon to all the other muntjacs.

Rapid and parallel chromosomal number reductions in muntjac deer inferred from mitochondrial DNA phylogeny

Muntjac deer (Muntiacinae, Cervidae) are of great interest in evolutionary studies because of their dramatic chromosome variations and recent discoveries of several new species. In this paper, we analyze the evolution of karyotypes of muntjac deer in the context of a phylogeny which is based on 1,844-bp mitochondrial DNA sequences of seven generally recognized species in the muntjac subfamily. The phylogenetic results support the hypothesis that karyotypic evolution in muntjac deer has proceeded via reduction in diploid number. However, the reduction in number is not always linear, i.e., not strictly following the order: 46-->14/13-->8/9-->6/7. For example, Muntiacus muntjak (2n = 6/7) shares a common ancestor with Muntiacus feae (2n = 13/14), which indicates that its karyotype was derived in parallel with M. feae's from an ancestral karyotype of 2n greater than or equal to 13/14. The newly discovered giant muntjac (Muntiacus vuquangensis) may represent another pa;allel reduction lineage from the ancestral 2n = 46 karyotype. Our phylogenetic results indicate that the giant muntjac is relatively closer to Muntiacus reevesi than to other muntjacs and may be placed in the genus Muntiacus. Analyses of sequence divergence reveal that the rate of change in chromosome number in muntjac deer is one of the fastest in vertebrates. Within the muntjac subfamily, the fastest evolutionary rate is found in the Fea's lineage, in which two species with different karyotypes diverged in around 0.5 Myr.

Phylogeny of fireflies (Coleoptera : Lampyridae) inferred from mitochondrial 16S ribosomal DNA, with references to morphological and ethological traits

We sequenced partial mitochondrial 16S ribosomal DNA (16S rDNA) of 18 firefly species from Southwest of China. Combined with homologous sequences previously reported, phylogenetic trees including Japanese, Korean and Chinese species were reconstructed by

MITOCHONDRIAL-DNA POLYMORPHISM IN NATURAL-POPULATIONS OF DROSOPHILA-ALBOMICANS(I)

The technique of mtDNA restriction fragments length polymorphism (RFLP) was used to survey the population structure of D. albomicans. Remarkable mtDNA polymorphism has been observed in D. albomicans populations. A total of 34 nucleomorphs were detected from 82 isofemale lines assayed by only 8 restriction enzymes. The cause and the effect of this phenomenon were discussed. As a result, it is suggested that a mechanism which maintains mtDNA diversity exists in this fly, and that the high intra-populational polymorphism could numerically conceal the extent of differentiation between populations. In addition, on the base of restriction maps, it was found that the mtDNA molecule of D. albomicans might be impacted by the selection pressure during its evolution process both on the nucleotide composition and on the functional regions.

鱇(鱼良)白鱼线粒体DNA控制区结构和种群遗传多样性分析

用特异性引物对鱇(鱼良)白鱼(Anabarilius grahami)DNA进行PCR扩增,获得了鱇(鱼良)白鱼线粒体DNA控制区基冈全序列(930bp).控制区T、C、A和G碱基组成为29.8%、22.5%、33.0和14.7%.对照其他已报道的鱼类控制区结构,对鱇(鱼良)白鱼控制区结构进行了分析,识别了其终止序列区、中央保守区和保守序列区,找到了终止相关的序列TAS以及保守序列(CSB-F、CSB-D、CSB-1、CSB-2、CSB-3).同时运用DNA分析软件对鱇(鱼良)白鱼一个驯养种群(中国科学院昆明动物研究所珍稀鱼类繁育中心)及两个自然地理种群(江川县明星鱼洞、江川县牛摩村)进行了遗传多样性分析.结果显示:两个自然种群存在较强基因交流,未出现遗传分化;人工驯养种群遗传多样性最高,种群复壮程度较好.