Mitochondrial DNA 16S rRNA Research Articles

Genetic vs community diversity patterns of macrobenthic species: preliminary results from the lagoonal ecosystem

1 - The use of molecular data derived from multispecies assemblages in order to test ecological theory has only recently been introduced in the scientific literature.2 - As a first step, we compared patterns of abiotic environment, polychaeta distribution and their genetic diversity in five lagoon ecosystems in Greece. Our results confirm the hypothesis that higher genetic diversity is expected in the populations of the species occurring in the transitional waters rather than of those occurring in the marine environment.3 - Patterns derived from the polychaete community level and from the mitochondrial DNA (16S rRNA) obtained from Nephtys hombergii and Hediste diversicolor showed convergence, indicating the potential use of molecular matrices as surrogates in community analysis.4 - Finally, the high correlation between the genetic diversity pattern of H. diversicolor and the phosphorus concentration in the sediments may imply the broadening of the hierarchic-response-tostress hypothesis towards lower than species level.

Mitochondrial COX2 G7598A Mutation May Have a Modifying Role in the Phenotypic Manifestation of Aminoglycoside Antibiotic-Induced Deafness Associated with 12S rRNA A1555G Mutation in a Han Chinese Pedigree

Recent studies suggest that certain mitochondrial haplogroup markers and some specific variants in mitochondrial haplogroup may also influence the phenotypic expression of particular mitochondrial disorders. In this report, the clinical, genetic, and molecular characterization were identified in a Chinese pedigree with the aminoglycoside antibiotic (AmAn)-induced deafness and nonsyndromic hearing loss (NSHL). The pathogenic gene responsible for this hereditary NSHL pedigree was determined by Microarray chip, which possessed the nine NSHL hot-spot mutations, including GJB2 (35delG, 176dell6bp, 235de1C, and 299delAT), GJB3 (538C>T), SLC26A4 (IVS7-2A>G and 2168A>G), and mitochondrial DNA (mtDNA) 12S rRNA (C1494T and A1555G). Only the homoplasmic A1555G mutation was detected, which was confirmed by direct sequencing. Also, real-time amplification refractory mutation system quantitative polymerase chain reaction methodology was performed to calculate the A1555G mutation load. The proband's complete mtDNA genome were amplified and direct sequencing was performed to determine the mitochondrial haplogroup and private mutations. The proband's mitochondrial haplogroup belonges to M7b1 and a private mutation MTCOX2 G7598A (p.Ala 5 Thr) is found. Phylogenetic analysis of COX2 polypeptide sequences demonstrates that the alanine residue is relatively conserved, but owing to the missense mutation (p.Ala 5 Thr), its side chain hydrophobicity will be changed, and what is more, as it is adjacent to a glutamine residue, which is highly conserved and hydrophilic, in an evolutionary stable domain; G7598A (p.Ala 5 Thr) may alter the protein secondary structure and physiological function of COX2 and, thus, aggravate the mitochondrial dysfunction conferred by the A1555G mutation. Furthermore, the G7598A mutation is absent in 100 unrelated healthy controls; therefore, G7598A (p.Ala 5 Thr) in the mitochondrial haplogoup M7b1 may have a modifying role, enhancing its penetrance and severity, in the AmAn-induced deafness and NSHL associated with 12S rRNA A1555G mutation in the Han Chinese pedigree.

Tracking the impact of Pliocene/Pleistocene sea level and climatic oscillations on the cladogenesis of the Cape legless skink, Acontias meleagris species complex, in South Africa

AbstractAimTo determine the geographical boundaries among cryptic lineages and examine the evolutionary drivers of cladogenesis within the Cape legless skink, Acontias meleagris species complex.LocationCoastal plains and adjacent interior of the Eastern, Northern and Western Cape provinces of South Africa.MethodsA total of 231 specimens from 55 localities were collected from the entire known distribution range of the A. meleagris complex. Partial sequence data were collected from two mitochondrial DNA loci, 16S rRNA and cytochrome c oxidase subunit I (COI), and one protein‐coding nuclear DNA locus, exophilin 5 (EXPH5). Phylogenetic, phylogeographical and population genetic analyses, together with divergence time estimation, were conducted on the DNA sequence data to examine evolutionary history and diversification within the species complex.ResultsMarked genetic structure was observed within the A. meleagris complex, and five clades were retrieved, most of which were statistically well supported. These five clades were also evident within the haplotypic analyses and were characterized by demographic stability. Cladogenesis was induced during the Pliocene/Pleistocene epochs, most likely as a result of oscillations in climate and sea level, and Neogene geomorphic phenomena. The Breede River Valley is an area of high genetic diversity and is likely to have served as a refugium.Main conclusionsLineage diversification and the current biogeographical patterning reflect the impact of sea level oscillations on historical coastal habitat availability. Fine‐scale differences between co‐distributed subterranean and supraterranean herpetofaunal taxa can be attributed to differences in life‐history traits amongst different habitat types. Historical evolutionary drivers within this subterranean species complex are inferred and discussed.

Molecular phylogenetic relationships of family Haemulidae (Perciformes: Percoidei) and the related species based on mitochondrial and nuclear genes

Haemulidae species are morphologically diversified fishes with wondrous and changeable coloration. These species are prevalent in global tropical, subtropical, and temperate inshore reef areas. Previous morphological classification within Haemulidae and some related families was problematic, and no comprehensive molecular evaluation was conducted on these groups. In this study, we revealed the first molecular phylogenetic analysis involving representative species within Haemulidae and the relevant families (Nemipteridae and Teraponidae). The analysis was performed using both mitochondrial DNA (16S rRNA) and nuclear DNA (TMO-4c4) genes to construct maximum parsimony, maximum likelihood, and Bayesian analysis tree topologies. The molecular phylogeny recovered well-resolved relationships within Haemulidae species and the problematic taxa. In the trees, the Haemulidae species (except for genus Hapalogenys) were divided into two distinct sister lineages, including grunts (Haemulinae) and sweetlips (Plectorhynchinae). Hapalogenys was positioned outside the major Haemulidae tribe and formed an independent group, which challenged the traditional taxonomy that Hapalogenys was classified into Haemulidae. The results did agree with most current studies that Hapalogenys was only distantly related to Haemulidae and could potentially be removed from this family. Additionally, the genus Diagramma was observed to be tightly grouped inside the clade Plectorhinchus, indicating its highly close affinity within Plectorhinchus. Regarding interfamily relationships, the phylogenetic constructions suggested distant relationships within two pairs: between Scolopsis and Haemulidae and between Teraponidae and Haemulidae. Scolopsis was revealed to be highly close with Nemipteridae, and Teraponidae was clustered in an independent group, which was in accordance with most current taxonomic studies.

Mitochondrial DNA Genetic Diversity of the Drywood TermitesIncisitermes minorandI. snyderi(Isoptera: Kalotermitidae)

The western drywood termite, Incisitermes minor (Hagen) and the light southern drywood termite I. snyderi (Light) are common drywood termites in southwestern and the southern United States, respectively. Despite the economic importance of these 2 species, no information exists on the mitochondrial genetic diversity of I. minor and I. snyderi. A molecular genetics study involving DNA sequencing of a portion of the mitochondrial DNA 16S rRNA gene was undertaken to determine the extent of genetic variation in I. minor and I. snyderi. A total of 12 haplotypes were observed for I. minor collected from Florida, Oregon, Arizona, Texas, Utah, and California. For I. snyderi, a total of 10 haplotypes were observed from the Bahamas, Florida, Georgia, and Texas. Genetic variation among I. minor haplotypes ranged from 0.7 to 3.7% and variation for I. snyderi ranged from 0.7 to 2.4%. Maximum parsimony and maximum likelihood analysis revealed 3 distinct clades for I. snyderi, whereas, I. minor had 2 distinct clades. This is the first study on mitochondrial genetic variation of the drywood termites I. minor and I. snyderi. There appears to be enough genetic variation within these 2 species for a molecular phylogeographic study, which may provide insight into dispersal and introductions of these species.

A novel mutation in the MITF may be digenic with GJB2 mutations in a large Chinese family of Waardenburg syndrome type II

Waardenburg syndrome type II (WS2) is associated with syndromic deafness. A subset of WS2, WS2A, accounting for approximately 15% of patients, is attributed to mutations in the microphthalmia-associated transcription factor (MITF) gene. We examined the genetic basis of WS2 in a large Chinese family. All 9 exons of the MITF gene, the single coding exon (exon 2) of the most common hereditary deafness gene GJB2 and the mitochondrial DNA (mtDNA) 12S rRNA were sequenced. A novel heterozygous mutation c.[742_743delAAinsT;746_747delCA] in exon 8 of the MITF gene co-segregates with WS2 in the family. The MITF mutation results in a premature termination codon and a truncated MITF protein with only 247 of the 419 wild type amino acids. The deaf proband had this MITF gene heterozygous mutation as well as a c.[109G>A]+[235delC] compound heterozygous pathogenic mutation in the GJB2 gene. No pathogenic mutation was found in mtDNA 12S rRNA in this family. Thus, a novel compound heterozygous mutation, c.[742_743delAAinsT;746_747delCA] in MITF exon 8 was the key genetic reason for WS2 in this family, and a digenic effect of MITF and GJB2 genes may contribute to deafness of the proband.

Discrimination of A1555G and C1494T Point Mutations in the Mitochondrial 12S rRNA Gene by On/Off Switch

The objective of this study was to apply the "on/off" switch consisting of 3' phosphorothioate-modified allele specific primers and exo(+) polymerase in single base discrimination of A1555G and C1494T mutations in the highly conserved sites of the mitochondrial 12S rRNA. The two point mutations are the hotspot mutations associated with either aminoglycoside antibiotics induced deafness or inherited nonsyndromic hearing loss. The PCR products of mitochondrial DNA (mtDNA) 12S rRNA gene were inserted into the pMD19-T vector for transformation into Escherichia coli JM109 competent cells for preparing wild-type pMD19-T/mt vector. Inverse PCR was carried out for mtDNA 12S rRNA gene C1494T and A1555G mutagenesis and DpnI endonuclease degradating methylated pMD19-T/mt vector existing in the inverse PCR products was carried out to construct the mutation-type pMD19-T/mtM vector. These constructed vectors were confirmed by DNA sequencing. Allelic specific primers targeting wild-type and mutation-type templates were designed with 3' terminal phosphorothioate modification. Two-directional primer extension was performed using Pfu polymerases. Amplified by exo(+) polymerase, allelic specific primers perfectly matching wild-type allele were extended while no products were produced from primers targeting point-mutated deafness-related allele. Similarly, allelic specific primers perfectly matching point-mutated deafness-related mutation-type allele were extended and no products were yielded from primers targeting wild-type allele. No specific product was observed in the primer extension reaction mediated by on/off switch in screening the mtDNA 12S rRNA gene harboring either C1494T or A1555G mutation in 40 healthy volunteers tested. These data suggest that the "off switch" mediated by exo(+) polymerase is highly reliable in the diagnosis of monogenic diseases and the novel "on/off" switch has enormous applications in systematic and extended screening of the12S rRNA gene A1555G and C1494T mutations. The established assay can be widely used not only for hearing loss patients but also for normal subjects before the use of aminoglycoside antibiotics.

Prenatal genetic counseling and instruction for deaf families by genetic test

Analyzed the molecular pathogenesis of probands by means of genetic test and assisted the local Family Planning Institute by providing prenatal genetic counseling and instruction for deaf families who eager to have more baby. Total of forty-three deaf families were recruited by two institutes for family planning from Guangzhou and Weifang. Forty-two families had one deaf child with normal hearing parents. One family was that parents and their child were all deaf. Genetic testing of GJB2, SLC26A4 and mitochondrial DNA (mtDNA) 12SrRNA were firstly performed in probands and their parents, following medical history, physical examination, auditory test and CT scan of temporal bone were completed. And then the genetic information and instruction were provided to each deaf family. Fifteen of these 43 families had positive results of genetic test. In fifteen families, one family was confirmed that the parents and their child all carried homozygous GJB2 mutations and the recurrence risk was 100%. Twelve families were confirmed that the probands carried homozygous/compound GJB2 or SLC26A4 mutations while their parents were GJB2 or SLC26A4 carriers, and the recurrence risk was 25%. One family was confirmed that the proband, diagnosed with enlarged vestibular aqueduct syndrome (EVAS) by CT scan, carried heterozygous SLC26A4 mutation from the mother, and the recurrence risk was still 25% based on the hereditary pattern of EVAS although another SLC26A4 mutation from the father was not found. One family was confirmed that the proband carried a heterozygous GJB2 mutation from the mother and the possibility to be GJB2 carrier for offsprings was 50%. The rest 28 families were that all probands and their parents did not carry GJB2, SLC26A4 and mtDNA 12SrRNA pathological mutation. Genetic testing can provide more accurate and useful prenatal genetic counseling and instruction to deaf families. Meanwhile, it is an ideal way to develop a cooperative relationship with the institute for family planning.

Multiplex Polymerase Chain Reaction Diagnostics of Bed Bug (Hemiptera: Cimicidae)

Cimex lectularius L. (Hemiptera: Cimicidae) is a widespread blood feeding pest of humans around the world, including North America, and has recently undergone a resurgence. A molecular diagnostic technique applying multiplex polymerase chain reaction (PCR) was developed to distinguish bed bug eggs, leg fragments, and degraded samples from other arthropods that frequently occur in human dwellings. A 410-428-bp region of the mitochondrial DNA 16S rRNA gene was used. To design C. lectularius-specific PCR primers, DNA sequences of various bed bug samples from the United States, Canada, and Australia, along with sequences of other Cimicidae and arthropods that often occur in dwellings, were considered. Based on DNA sequence variation, one reverse PCR primer specific for C. lectularius was identified. Multiplex PCR using three primers will yield a 417- and 140-bp amplicon for C. lectularius and a single 410-428-bp amplicon for other taxa. This assay was successful in identifying C. lectularius eggs, leg fragments, and degraded samples. This technique should provide a reliable, quick, and economical technique for identifying C. lectularius, when morphological identification is not possible.

Systematic relationships of Oriental tiny frogs of the family Microhylidae (Amphibia, Anura) as revealed by mtDNA genealogy

We estimated the genealogical relationships and assessed systematic relationships among 45 out of 89 named species and four unnamed taxa from 11 of 14 genera of the Oriental microhylids from 1767bp sequences of the mitochondrial DNA genes 12S rRNA and 16S rRNA using maximum parsimony, maximum likelihood, and Bayesian inference methods. Monophyly was rejected for the subfamily Microhylinae, and our data reveal four well-supported clades whose relationships to each other are unresolved: (A) Microhyla, Calluella, and Glyphoglossus, (B) Chaperina, (C) Kaloula, Phrynella, and Metaphrynella, and (D) Micryletta. They were genetically as divergent from each other as from another Oriental subfamily Kalophryninae, and could be recognized as distinct subfamilies. Within Clade A, our data reveal three well-supported subclades whose relationships to each other are unresolved: (AI) Microhyla-I, (AII) Calluella and Glyphoglossus, and (AIII) Microhyla-II. Of the two enigmatic Malaysian genera, whose subfamilial placement has been undetermined, Phrynella was found to be the sister species of Metaphrynella in Clade C, whereas Gastrophrynoides was grouped in the Papua-Australian subfamily Asterophryinae. Currently recognized subgenera and species groups within Microhyla based on morphology were not supported phylogenetically, and require thorough reassessments.

D011 Radio-anatomical analysis of temporal bones for access to the round window

The study is to identify the carrier rate of common deafness mutation in Chinese pregnant women via detecting deafness gene mutations with gene chip.The pregnant women in obstetric clinic without hearing impairment and hearing disorders family history were selected. The informed consent was signed. Peripheral blood was taken to extract genomic DNA. Application of genetic deafness gene chip for detecting 9 mutational hot spot of the most common 4 Chinese deafness genes, namely GJB2 (35delG, 176del16bp, 235delC, 299delAT), GJB3 (C538T) ,SLC26A4 ( IVS72A>G, A2168G) and mitochondrial DNA 12S rRNA (A1555G, C1494T) . Further genetic testing were provided to the spouses and newborns of the screened carriers.Peripheral blood of 430 pregnant women were detected, detection of deafness gene mutation carriers in 24 cases(4.2%), including 13 cases of the GJB2 heterozygous mutation, 3 cases of SLC26A4 heterozygous mutation, 1 cases of GJB3 heterozygous mutation, and 1 case of mitochondrial 12S rRNA mutation. 18 spouses and 17 newborns took further genetic tests, and 6 newborns inherited the mutation from their mother.The common deafness genes mutation has a high carrier rate in pregnant women group, 235delC and IVS7-2A>G heterozygous mutations are common.

C042 Auditory brainstem implantation outcomes: Longitudinal study results

To assess the molecular etiology of nonsyndromic sensorineural hearing loss (NSHL) in members of an affected Chinese family.Common hearing-related genes including gap junction beta 2 (GJB2), SLC26A4, mitochondrial DNA 12S rRNA, GJB3 and GJB6 were examined in a family consisting of a normal hearing father, an NSHL-affected mother, one normal-hearing child and three NSHL-affected children. Specific primers were used in polymerase chain reactions to amplify the coding regions of the above genes from the peripheral blood DNA from each family member, and the genes were analyzed by direct sequencing. The subjects were evaluated for phenotypic characterization using audiometric testing and radiological examination of the inner ear.Pathogenic mutations in the GJB2 gene were identified. The affected mother showed a heterozygous G → A transition at nucleotide 232, resulting in an alanine to threonine substitution at codon 78 (p.A78T), and the normal hearing father had a c.35insG insertion mutation. The three affected children displayed heterozygosity for the GJB2 mutations, showing a previously unreported combination of c.35insG and c.232G>A.The GJB2 mutations account for a significant proportion of NSHL in affected individuals worldwide. Genetic and audiological data analysis of a Chinese family with NSHL revealed a novel c.35insG/c.232G>A compound heterozygous state. Our results highlight the complexity of the GJB2 genotypes and phenotypes.

Genetic divergence and phylogeny of turtles inferred from mitochondrial DNA 16SrRNA sequence

In order to investigate the genetic divergence and phylogeny of turtles,mitochondrial DNA 16SrRNA gene segment sequences of 13 turtle individuals were obtained by PCR amplification and sequencing.16SrRNA sequences of other 47 turtles from NCB were downloaded and its phylogenetic characters were analyzed together with their own 13 sequences.The results were as follows:480 bp consensus sequences of 16SrRNA were obtained from these 60 sequences after aligned.Twenty hundreds and twenty nine variable sites were detected in all turtle individuals,accounting for 47.7% of total variable sites,with 186 parsim-informative and 80 indels.The average contents of A,T,G,and C were 33.6%,24.3%,18.5%,and 23.7%,respectively.The Ts:Tv ratio was 1.95.The K-2-P distances between the seven hinged turtles were 0.004-0.063,with average value 0.03;between 17 genus within Geoemydidae 0.053-0.120,with average 0.091;and between 8 families within Cryptodira(excluding Platysternon megacephalum) 0.071-0.259,with average 0.169.The results indicate that family Emydidae is the sister taxon to Geoemydidae plus Testudinidae,and Geoemydidae is closer to Testudinidae compared to Emydidae;the taxonomica status of Chinemys should be revised,and classified into Genus Mauremys,and that Pyxidea should be classified into Cuora;the results do not support the idea that the genus Cuora should be divided into two genera as Cuora and Cistoclemmys.

Assessing the molecular phylogeny of a near extinct group of vertebrates: the Neotropical harlequin frogs (Bufonidae; Atelopus)

Neotropical harlequin frogs, Atelopus, are a species-rich bufonid group. Atelopus monophyly has been suggested but intergeneric, interspecific and intraspecific relationships are poorly understood. One reason is that morphological characters of harlequin frogs are often difficult to interpret, making species delimitations difficult. Molecular analyses (DNA barcoding, phylogeny) may be helpful but sampling is hampered as most of the more than 100 Atelopus species have undergone severe population declines and many are possibly extinct. We processed mitochondrial DNA (12S and 16S rRNA) of 28 available ingroup samples from a large portion of the genus’ geographic range (Bayesian Inference, Maximum Likelihood). Our samples constitute a monophyletic unit, which is sister to other bufonid genera studied including the Andean genus Osornophryne. In contrast to previous morphological studies, our results suggest that Osornophryne is neither sister to Atelopus nor nested within it. Within Atelopus, we note two major clades with well supported subclades, one Amazonian–Guianan Clade (Flavescens-spumarius Clade plus Tricolor Clade) and an Andean–Chocó–Central American Clade (Varius Clade plus all other Atelopus). The first mentioned includes all species that possess a middle ear (i.e. stapes) except for A. seminiferus lacking it (like all remaining Atelopus). Previously proposed species groups based on frog-like versus toad-like overall appearance (i.e. Longirostris and Ignescens Groups) or phalangeal reduction in the thumb (i.e. Flavescens Group) are not monophyletic in our phylogeny, thus characters used to define them are not considered synapomorphies. We show that genetic divergence can be high between species belonging to different clades, in spite of their phenetic similarity (e.g. A. pulcher, Atelopus sp. 2). On the other hand, within the same clade, colour can vary tremendously, while genetic divergence is low (e.g. A. flavescens and allies). These observations demonstrate that Atelopus taxonomy is complicated and that an integrative approach is required before ‘splitting’ or ‘lumping’ nominal species.

A new species of snake eel, Pisodonophis sangjuensis (Anguilliformes: Ophichthidae) from Korea

A new snake eel, Pisodonophis sangjuensis, is described based on 24 specimens collected from the South Sea of Korea (water depth 5–100 m) between 2005 and 2010. This species is characterized by the following morphological features: fleshy protrusions before and behind the posterior nostril; 1–2 regular rows of conical teeth in both jaws, prevomer and vomer are slightly separated from each other; the origin of the dorsal fin above the middle of the pectoral fin; and the pectoral fin is rounded and not elongated. Pisodonophis sangjuensis is most similar to P. cancrivorus in morphology, but the two species differ in their teeth shape (conical in P. sangjuensis vs. granular in P. cancrivorus), and their numbers of vertebrae (143–153 vs. 153–164, respectively). Pisodonophis sangjuensis differs from P. boro in the origin of the dorsal fin (above the middle of the pectoral fin in P. sangjuensis vs. far behind the pectoral fin in P. boro), their numbers of vertebrae (143–153 vs. 170–177, respectively), and their teeth shape (conical in P. sangjuensis vs. granular in P. boro). Pisodonophis sangjuensis is also easily distinguishable morphologically from the remaining seven Pisodonophis spp. worldwide. Molecular analysis using mitochondrial DNA 12S rRNA sequences supported that P. sangjuensis is a new species because of the considerable genetic distance from what appears to be its most closely related species, P. cancrivorus (d=0.068).

DNA-Based Identification of Fish Species Implicated in Puffer Fish Poisoning

A method for identification of fish species using three different mitochondrial DNA regions, 16S rRNA, cytochrome b and cytochrome c gene fragments, was investigated. The combined use of all three regions enabled reliable species identification in not only raw fish, but also dried, seasoned and boiled fish, products. Furthermore, the method was applicable even to vomitus from a patient involved in a puffer fish poisoning incident. However, further improvement is necessary to discriminate between closely related species such as Takifugu rubripes and T. chinensis, because they showed close similarity in the nucleotide sequences in the three gene fragments analyzed in this study.

Application of mitochondrial genes sequences for measuring the genetic diversity of Arabian oryx

Arabian oryx (Oryx leucoryx) had faced extinction in the wild more than three decades ago and was saved by the prudent efforts of captive breeding programs. A clear understanding of the molecular diversity of contemporary Arabian oryx population is important for the long term success of captive breeding and reintroduction of this potentially endangered species. We have sequenced the segments of mitochondrial DNA including12S rRNA, 16S rRNA, cytochrome b (Cyt-b) and control region (CR) genes of 24 captive-bred and reintroduced animals. Although the sequences of 12S rRNA, 16S rRNA and Cyt-b were found to be identical for all the samples, typical sequence variations in the CR gene were observed in the form of 7 haplotypes. One of these haplotypes has been reported earlier while the remaining 6 haplotypes are novel and represent different lineages from the founders. The haplotype and nucleotide diversities were found to be 0.789 and 0.009 respectively. The genetic distances among the 7 mtDNA haplotypes varied from 0.001 to 0.017. These findings are of potential relevance to the management of captive breeding programs for the conservation of Arabian oryx.

Identifying the confounding factors in resolving phylogenetic relationships in Vespertilionidae

Resolving phylogenetic relationships within Vespertilionidae has been difficult, with large data sets (>100 taxa, >7 kilobases) resolving portions of the phylogeny but leaving intertribal relationships within the Vespertilioninae unresolved. As a result the evolutionary history of the most speciose chiropteran family is largely unknown. The presence of short internodes followed by long terminal branches relative to other chiropteran phylogenies suggests that evolutionary rates of DNA substitution and lineage diversification could be inhibiting phylogenetic resolution. To test this hypothesis we obtained sequences of the mitochondrial DNA (mtDNA) 12s rRNA, tRNAVAL, and 16s rRNA, and the nuclear exon RAG2, resulting in more than 3 kilobases of digenomic DNA sequence data for representatives of all subfamilies and tribes within Vespertilionidae and Phyllostomidae, a family of bats that radiated at approximately the same time as Vespertilionidae. Analyses revealed that substitution rates for Vespertilionidae were significantly higher than those for Phyllostomidae, with the majority of fast-evolving lineages found within Vespertilioninae. Cladogenesis analyses characterized the vespertilionid radiation as compressed toward the root, with a rapid initial diversification, but the phyllostomid diversification was much more gradual. We suggest that ecological differences between tropical and temperate environments could have influenced diversification rates for Vespertilionidae and Phyllostomidae.

Molecular epidemiological analysis of mitochondrial DNA12SrRNA A1555G, GJB2, and SLC26A4 mutations in sporadic outpatients with nonsyndromic sensorineural hearing loss in China

Conclusion: GJB2 mutation was frequent in sporadic outpatients and its mutation frequency was significant higher in the prelingual group than in the postlingual group, whereas the mutation of mtDNA A1555G and SLC26A4 was very rare in Chinese sporadic outpatients with nonsyndromic sensorineural hearing loss (NSHL). Standard and comprehensive inclusion and grouping criteria are necessary for epidemiological studies of deafness-related gene mutations. Objectives: This study aimed to examine the mutations of the three common deafness genes GJB2, SLC26A4, and mtDNA A1555G in Chinese sporadic outpatients with NSHL and to discuss the factors that influence the detection accuracy of mutation frequencies. Methods: A total of 473 sporadic NSHL patients without any type of inner ear malformation, including both prelingual and postlingual groups were enrolled in this study. Three genes of mtDNA A1555G, GJB2, and SLC26A4 were screened for mutation in our study cohort. A chi-square test was performed to compare mutation frequencies between prelingual and postlingual groups. Results: The mutation frequencies of MtDNA A1555G, GJB2, and SLC26A4 were 1.63%, 13.63%, and 0%, respectively, in our study cohort. The mutational hot spot of GJB2 was c.235delC, whose allele frequency was 12.68% in sporadic outpatients. Mutation frequency of GJB2 in the prelingual group was significantly higher than in the postlingual group (p < 0.05).

참서대과(Pisces: Cynoglossidae) 자어 2종의 미토콘드리아 DNA에 의한 형태동정의 타당성

Three specimens of Cynoglossidae larvae were collected from the southern Korean Sea in May and August of 2009, and were identified using morphological and molecular analysis. Specimens were divided into two groups based on the number of elongated dorsal fin rays on the top of the head: Cynoglossidae sp. A was defined as having two elongated dorsal fin rays, while Cynoglossidae sp. B possessed a single elongated dorsal fin ray. One specimen of Cynoglossidae sp. A, a post-larva with a notochord length (NL) of 5.8 mm was thought to be a Cynoglossus joyneri larva based on the presence of 115 dorsal pterogiophores, 85 anal pterogiophores, and 50 myomeres. Two specimens of Cynoglossidae sp. B, a 4.1 mm NL larva and a 11.3 mm NL juvenile, were thought to be Cynoglossus abbreviatus based on the presence of yolk in the former and 133 dorsal fin rays, 105 anal fin rays, and 63 myomeres in the latter. To test this morphology-based identification, molecular analysis was conducted using 419-422 bp of mitochondrial DNA 16S rRNA. Cynoglossidae sp. A was clearly matched to a Cynoglossus joyneri adult (d=0.000) and Cynoglossidae sp. B clustered closely with Cynoglossus abbreviatus adults (d=0.002). A neighbor-joining tree supported this robust relationship (bootstrap value=100%). Therefore, these molecular data validate the morphological identification of the two Cynoglossidae larval species.