Sequence of mitochondrial DNA cytochrome oxidase II in Cryptopygus nanjiensis and phylogeny of apterygota

The mitochondrial cytochrome oxidase II (Co II) from four different apterygotens Cryptopygus nanjiensis (Collembola), Neanura latior (Collembola), Gracilentulus maijiawensis (Protura) and Lepidocampa weberi (Diplura) were sequenced. Their A+T content, number of nucleotide substitutions, TV/TV ratio; and Tamura-Nei's distance were calculated. A series of phylogenetic trees were constructed by parsimony and distance methods using a crustacean Artemia franciscana as outgroup, Finally the evolutionary trend A+T content of CO II genetic divergence and phylogenetic relationship of apterygotan groups were discussed.

Evolutionary history of the mtDNA 9-bp deletion in Chinese populations and its relevance to the peopling of east and southeast Asia

In total, 1218 Chinese from twelve ethnic groups and nine Han geographic groups were screened for the mtDNA 9-bp deletion motif. The frequency of the 9-bp deletion in all samples was 14.7% but ranged from 0% to 32% in the various ethnic groups. Three individuals had a triplication of the 9-bp segment. Phylogenetic and demographic analyses of the mtDNA hypervariable segment 1 (HVS1) sequences suggest that the 9-bp deletion occurred more than once in China. The majority of the Chinese deletion:haplotypes (about 90%) have a common origin as a mutational event following an initial expansion of modem humans in eastern Asia. Other deletion haplotypes and the three haplotypes with a 9-bp triplication may have arisen independently in the Chinese, presumably by replication error. HVS1 haplotype analysis suggests two possible migration routes of the 9-bp deletion in east and southeast Asia. Both migrations originated in China with one route leading to the Pacific Islands via Taiwan, the other to southeast Asia and possibly the Nicobar Islands. Along both routes of peopling, a decrease in HVS1 diversity of the mtDNA haplotypes is observed. The "Polynesian motif (16217T/C, 16247A/G, and 16261C/T)" and the 16140T/C, 16266C/A, or C/G polymorphisms appear specific to each migration route.

Taxonomic status of the white-head langur (Trachypithecus francoisi leucoscephalus) inferred from allozyme electrophoresis and random amplified polymorphism DNA (RAPD)

Six sample specimens of Trachypithecus francoisi and 3 of T. leucocephalus were analyzed by use of allozyme electrophoresis and random amplified polymorphism DNA (RAPD) in order to clarify the challenged taxonomic status of the white-head langur. Among the 44 loci surveyed, only 1 locus (PGM-2) was found to be polymorphic. Nei's genetic distance was 0.0025. In total, thirty 10-mer arbitrary primers were used for RAPD analysis, of which 22 generated clear bands. Phylogenetic trees were constructed based on genetic distances using neighbor-joining and UPGMA methods. The results show that T. francoisi and T: leucocephalus are not monophyletic. T. francoisi from Guangxi, China and Vietnam could not be clearly distinguished, and they are not divided into 2 clusters. A t-test was performed to evaluate between genetic distances within and between T. leucocephalus and T. francoisi taxa groups. The statistical test shows that the taxa group within T: leucocephalus and T: francoisi does not significantly differ from that between T: leucocephalus and T: francoisi at the 5% level. Our results suggest that the level of genetic differentiation between T, leucocephalus and T. francoisi is relatively low. Recent gene flow might exist between T. francoisi and T. leucocephalus. Combining morphological features, geographical distribution, allozyme data, RAPD data, and mtDNA sequences, we suggest that the white-head langur might be a subspecies of T. francoisi.

Phylogeny of higher taxa of Hexapoda according to 12sRNA sequences

The phylogenetic relationship of Hexapoda has been debated for a long time, which will be resolved mainly depending on the settlement of monophyly, affinities and interrelationships among Protura, Collembola and Diplura. Mitochondrial 12sRNA gene about 35

Phylogeny of East Asian mitochondrial DNA lineages inferred from complete sequences

The now-emerging mitochondrial DNA ( mtDNA) population genomics provides information for reconstructing a well-resolved mtDNA phylogeny and for discerning the phylogenetic status of the subcontinentally specific haplogroups. Although several major East Asian mtDNA haplogroups have been identified in studies elsewhere, some of the most basal haplogroups, as well as numerous minor subhaplogroups, were not yet determined or fully characterized. To fill the lacunae, we selected 48 mtDNAs from >2,000 samples across China for complete sequencing that cover virtually all ( sub) haplogroups discernible to date in East Asia. This East Asian mtDNA phylogeny can henceforth serve as a solid basis for phylogeographic analyses of mtDNAs, as well as for studies of mitochondrial diseases in East and Southeast Asia.

A phylogeny of Chinese species in the genus Phrynocephalus (Agamidae) inferred from mitochondrial DNA sequences

We investigated the phylogenetic relationships among most Chinese species of lizards in the genus Phrynocephalus (118 individuals, collected from 56 populations of 14 well-defined species and several unidentified specimens) using four mitochondrial gene fragments (12S rRNA, 16S rRNA, cytochrome b, and ND4-tRNA(LEU)). The partition-homogeneity tests indicated that the combined dataset was homogeneous, and maximum-parsimony (MP), neighbor-joining (NJ), maximum-likelihood (ML) and Bayesian (BI) analyses were performed on this combined dataset (49 haplotypes including outgroups for 2058 bp in total). The maximum-parsimony analysis resulted in 24 equally parsimonious trees, and their strict consensus tree shows that there are two major clades representing the Chinese Phrynocephalus species: the viviparous group (Clade A) and the oviparous group (Clade B). The trees derived from Bayesian, ML. and NJ analyses were topologically identical to the MP analysis except for the position of P. mystaceus. All analyses left the nodes for the oviparous group, the most basal clade within the oviparous group, and P. mystaceus unresolved. The phylogenies further suggest that the monophyly of the viviparous species may have resulted from vicariance, while recent dispersal may have been important in generating the pattern of variation among the oviparous species. (C) 2003 Elsevier Science (USA). All rights reserved.

Adaptive diversification of bitter taste receptor genes in mammalian evolution

The diversity and evolution of bitter taste perception in mammals is not well understood. Recent discoveries of bitter taste receptor (T2R) genes provide an opportunity for a genetic approach to this question. We here report the identification of 10 and 30 putative T2R genes from the draft human and mouse genome sequences, respectively, in addition to the 23 and 6 previously known T2R genes from the two species. A phylogenetic analysis of the T2R genes suggests that they can be classified into three main groups, which are designated A, B, and C. Interestingly, while the one-to-one gene orthology between the human and mouse is common to group B and C genes, group A genes show a pattern of species- or lineage-specific duplication. It is possible that group B and C genes are necessary for detecting bitter tastants common to both humans and mice, whereas group A genes are used for species-specific bitter tastants. The analysis also reveals that phylogenetically closely related T2R genes are close in their chromosomal locations, demonstrating tandem gene duplication as the primary source of new T2Rs. For closely related paralogous genes, a rate of nonsynonymous nucleotide substitution significantly higher than the rate of synonymous substitution was observed in the extracellular regions of T2Rs, which are presumably involved in tastant-binding. This suggests the role of positive selection in the diversification of newly duplicated T2R genes. Because many natural poisonous substances are bitter, we conjecture that the mammalian T2R genes are under diversifying selection for the ability to recognize a diverse array of poisons that the organisms may encounter in exploring new habitats and diets.

Can the occurrence of rare insertion/deletion polymorphisms in human mtDNA be verified from phylogeny?

Due to its specific characteristics, such as maternal inheritance and absence of recombination, each mtDNA belongs to certain monophyletic clade in the rooted mtDNA tree (haplogroup) according to the mutations it harbors. Rare mutation (excluding parallel mutation) occurring at multiple times in different haplogroups could thus be a potential reading error according to the mtDNA phylogeny. This experience has been widely used in double-checking the credibility of the rare mutations in human mtDNA sequences. However, no test has been performed so far for the feasibility of applying this strategy to the rare insertion/deletion (indel) events in mtDNA sequences. In this study, we attempted to relate the rare indels in mtDNAs to their haplogroup status in a total of 2352 individuals from 50 populations in China. Our results show that the insertion of A at position 16259 is restricted to a subclade of haplogroup C and can be verified. The other indel polymorphisms, which occur in the repeat of the deleted or inserted nucleotide(s), may not be distinguished from phantom mutations from a phylogenetic point of view. Independently and multiply sequencing the fragment with the indel is the best and the most reliable way for confirmation.

Evolution and biogeography of talpid moles from continental East Asia and the Japanese islands inferred from mitochondrial and nuclear gene sequences

We sequenced the cytochrome b gene from two little-studied mammal species from the highlands of Southwest China, the long-tailed mole Scaptonyx fusicaudus and the gracile shrew-like mole Uropsilus gracilis. This data was used to examine the phylogenetic r

Analysis of 18S rRNA gene of Octostigma sinensis (Projapygoidea : Octostigmatidae) supports the monophyly of Diplura

The phylogenetic position of Diplura within Hexapoda has been controversial. There are three major lineages in Diplura: Campodeoidea, Projapygoidea, and Japygoidea. However, most of the previous studies were restricted to Campodeoidea and Japygoidea. Unti

Molecular phylogeny and biogeography of Oriental voles: genus Eothenomys (Muridae, Mammalia)

Oriental voles of the genus Eothenomys are predominantly distributed along the Southeastern shoulder of the Qinghai-Tibetan Plateau. Based on phylogenetic analyses of the mitochondrial cytochrome b gene (1143 bp) obtained from 23 specimens (eight species)

Phylogeny of the bears (Ursidae) based on nuclear and mitochondrial genes

The taxomic classification and phylogenetic relationships within the bear family remain argumentative subjects in recent years. Prior investigation has been concentrated on the application of different mitochondrial (mt) sequence data, herein we employ tw

Molecular phylogeny of the genus Paramesotriton (Caudata : Salamandridae)

To elucidate the phylogeny of the genus Paramesotriton (Caudata: Salamandridae), we investigated three mitochondrial DNA gene fragments (1207 bp in total) of cytochrome b, ND2, and ND4 for its six recognized species. The phylogenetic relationships within

Mitochondrial diversity and phylogeographic structure of Chinese domestic goats

China has numerous native domestic goat breeds, but so far there has been no extensive study on genetic diversity, population demographic history, and origin of Chinese goats. Here, we examined the genetic diversity and phylogeographic structure of Chinese domestic goats by determining a 481-bp fragment of the first hypervariable region of mitochondrial DNA (mtDNA) control region from 368 individuals representing 18 indigenous breeds. Phylogenetic analyses revealed that there were four mtDNA lineages (A-D) identified in Chinese goats, in which lineage A was predominant, lineage B was moderate, and lineages C and D were at low frequency. These results further support the multiple maternal origins of domestic goats. The pattern of genetic variation in goat mtDNA sequences indicated that the two larger lineages A and B had undergone population expansion events. In a combined analysis of previously reported sequences and our sequences belonging to lineage B, we detected two subclades, in which one was unique to eastern Asia and another was shared between eastern and southern Asia. A larger genetic variation in eastern Asia than southern Asia and the pattern of phylogeographic variation in lineage B suggest that at least one subclade of lineage B originated from eastern Asia. There was no significant geographical structuring in Chinese goat populations, which suggested that there existed strong gene flow among goat populations caused by extensive transportation of goats in history. (c) 2005 Elsevier Inc. All rights reserved.

Independent origin of the growth hormone gene family in New World monkeys and Old World monkeys/hominoids

The growth hormone (GH) gene family represents an erratic and complex evolutionary pattern, involving many evolutionary events, such as multiple gene duplications, positive selection, the birth-and-death process and gene conversions. In the present study, we cloned and sequenced GH-like genes from three species of New World monkeys (NWM). Phylogenetic analysis strongly suggest monophyly for NWM GH-like genes with respect to those of Old World monkeys (OWM) and hominoids, indicating that independent gene duplications have occurred in NWM GH-like genes. There are three main clusters of genes in putatively functional NWM GH-like genes, according to our gene tree. Comparison of the ratios of nonsynonymous and synonymous substitutions revealed that these three clusters of genes evolved under different kinds of selective pressures. Detailed analysis of the evolution of pseudogenes showed that the evolutionary pattern of this gene family in platyrrhines is in agreement with the so-called birth-and-death process.