scholarly journals Mutations as Missing Data: Inferences on the Ages and Distributions of Nonsynonymous and Synonymous Mutations

Genetics ◽  
2001 ◽  
Vol 159 (1) ◽  
pp. 401-411
Author(s):  
Rasmus Nielsen
Keyword(s):  
Missing Data ◽  
Dna Sequences ◽  
Sequence Data ◽  
Published Data ◽  
Data Sets ◽  
Effective Population ◽  
Gene Genealogy ◽  
Synonymous Mutations ◽  
Dna Sequence Data ◽  
Slightly Deleterious Mutations

AbstractThis article describes a new Markov chain Monte Carlo (MCMC) method applicable to DNA sequence data, which treats mutations in the genealogy as missing data. The method facilitates inferences regarding the age and identity of specific mutations while taking the full complexities of the mutational process in DNA sequences into account. We demonstrate the utility of the method in three applications. First, we demonstrate how the method can be used to make inferences regarding population genetical parameters such as θ (the effective population size times the mutation rate). Second, we show how the method can be used to estimate the ages of mutations in finite sites models and for making inferences regarding the distribution and ages of nonsynonymous and synonymous mutations. The method is applied to two previously published data sets and we demonstrate that in one of the data sets the average age of nonsynonymous mutations is significantly lower than the average age of synonymous mutations, suggesting the presence of slightly deleterious mutations. Third, we demonstrate how the method in general can be used to evaluate the posterior distribution of a function of a mapping of mutations on a gene genealogy. This application is useful for evaluating the uncertainty associated with methods that rely on mapping mutations on a phylogeny or a gene genealogy.

Phylogeny of the water strider genus Aquarius Schellenberg (Heteroptera: Gerridae) based on nuclear and mitochondrial DNA sequences and morphology

2000 ◽  
Vol 31 (1) ◽  
pp. 71-90 ◽  
Author(s):  
Nils Møller Andersen ◽  
Jakob Damgaard ◽  
Felix A.H. Sperling
Keyword(s):  
Dna Sequences ◽  
Sequence Data ◽  
Mitochondrial Gene ◽  
Nuclear Gene ◽  
Molecular Data ◽  
Morphological Data ◽  
Published Data ◽  
Data Sets ◽  
Gene Encoding ◽  
Data Set

AbstractWe examined phylogenetic relationships among gerrid water striders of the genus Aquarius Schellenberg using molecular and morphological characters. The molecular data sets included 780 bp sequence data from the mitochondrial gene encoding cytochrome oxidase subunit I (COI), and 515 bp sequence data from the nuclear gene encoding elongation factor I alpha (EF-1α). The morphological data set was a slightly modified version of a previously published data set. We included all 17 known species and one subspecies of Aquarius as well as five species from three related genera, Gigantometra gigas, Limnoporus esakii, L. rufoscutellatus, Gerris pingreensis, and G. lacustris. Unweighted parsimony analyses of the COI data set gave a single most parsimonious tree (MPT) with a topology quite similar to the morphological tree. Parsimony analyses of the EF-1α data set gave 3 MPT's and a strict consensus of these trees gave a tree with a slightly different topology. A combined analysis of the three data sets gave a single MPT with the same topology as for the morphological data set alone. The phylogeny of Aquarius presented here supports the monophyly of the A. najas, remigis, conformis and paludum species groups as well as previous hypotheses about their relationships. On the other hand, the inclusion of molecular data weakens the support for the monophyly of the genus Aquarius, and questions the specific status of the eastern North American A. nebularis (as separate from A. conformis) and members of the Nearctic A. remigis group. Finally, we discuss the implications of the reconstructed phylogeny in the biogeography and ecological phylogenetics of Aquarius.

scholarly journals A Comparison of Methods for Estimating Substitution Rates from Ancient DNA Sequence Data

2017 ◽  
Author(s):  
K. Jun Tong ◽  
David A. Duchêne ◽  
Sebastián Duchêne ◽  
Jemma L. Geoghegan ◽  
Simon Y.W. Ho
Keyword(s):  
Bayesian Inference ◽  
Least Squares ◽  
Ancient Dna ◽  
Dna Sequences ◽  
Sequence Data ◽  
Evolutionary Rates ◽  
High Rate ◽  
Rate Variation ◽  
Data Sets ◽  
Dna Sequence Data

AbstractThe estimation of evolutionary rates from ancient DNA sequences can be negatively affected by among-lineage rate variation and non-random sampling. Using a simulation study, we compared the performance of three phylogenetic methods for inferring evolutionary rates from time-structured data sets: root-to-tip regression, least-squares dating, and Bayesian inference. Our results show that these methods produce reliable estimates when the substitution rate is high, rate variation is low, and samples of similar ages are not phylogenetically clustered. The interaction of these factors is particularly important for Bayesian estimation of evolutionary rates. We also inferred rates for time-structured mitogenomic data sets from six vertebrate species. Root-to-tip regression estimated a different rate from least-squares dating and Bayesian inference for mitogenomes from the horse, which has high levels of among-lineage rate variation. We recommend using multiple methods of inference and testing data for temporal signal, among-lineage rate variation, and phylo-temporal clustering.

The Age of Nonsynonymous and Synonymous Mutations in Animal mtDNA and Implications for the Mildly Deleterious Theory

Genetics ◽  
1999 ◽  
Vol 153 (1) ◽  
pp. 497-506 ◽  
Author(s):  
Rasmus Nielsen ◽  
Daniel M Weinreich
Keyword(s):  
Dna Sequences ◽  
Purifying Selection ◽  
Data Sets ◽  
Deleterious Mutations ◽  
Synonymous Mutations ◽  
Weak Evidence ◽  
Mitochondrial Data ◽  
The Mean ◽  
Excess Number ◽  
Neutral Mutations

Abstract McDonald/Kreitman tests performed on animal mtDNA consistently reveal significant deviations from strict neutrality in the direction of an excess number of polymorphic nonsynonymous sites, which is consistent with purifying selection acting on nonsynonymous sites. We show that under models of recurrent neutral and deleterious mutations, the mean age of segregating neutral mutations is greater than the mean age of segregating selected mutations, even in the absence of recombination. We develop a test of the hypothesis that the mean age of segregating synonymous mutations equals the mean age of segregating nonsynonymous mutations in a sample of DNA sequences. The power of this age-of-mutation test and the power of the McDonald/Kreitman test are explored by computer simulations. We apply the new test to 25 previously published mitochondrial data sets and find weak evidence for selection against nonsynonymous mutations.

scholarly journals Characterization of an unusually conserved AluI highly reiterated DNA sequence family from the honeybee, Apis mellifera.

Genetics ◽  
1993 ◽  
Vol 134 (4) ◽  
pp. 1195-1204
Author(s):  
S Tarès ◽  
J M Cornuet ◽  
P Abad
Keyword(s):  
Apis Mellifera ◽  
Dna Sequence ◽  
Dna Sequences ◽  
Sequence Data ◽  
Sequence Divergence ◽  
Repeated Sequence ◽  
Consensus Sequences ◽  
Dna Sequence Data ◽  
Repeat Class ◽  
Honeybee Subspecies

Abstract An AluI family of highly reiterated nontranscribed sequences has been found in the genome of the honeybee Apis mellifera. This repeated sequence is shown to be present at approximately 23,000 copies per haploid genome constituting about 2% of the total genomic DNA. The nucleotide sequence of 10 monomers was determined. The consensus sequences is 176 nucleotides long and has an A + T content of 58%. There are clusters of both direct and inverted repeats. Internal subrepeating units ranging from 11 to 17 nucleotides are observed, suggesting that it could have evolved from a shorter sequence. DNA sequence data reveal that this repeat class is unusually homogeneous compared to the other class of invertebrate highly reiterated DNA sequences. The average pairwise sequence divergence between the repeats is 2.5%. In spite of this unusual homogeneity, divergence has been found in the repeated sequence hybridization ladder between four different honeybee subspecies. Therefore, the AluI highly reiterated sequences provide a new probe for fingerprinting in A. m. mellifera.

Generic Delimitations and Relationships of the Cape Genera Capnophyllum, Dasispermum, and Sonderina, the North African Genera Krubera and Stoibrax, and a New Monotypic Genus of the Subfamily Apioideae (Apiaceae)

2009 ◽  
Vol 34 (3) ◽  
pp. 580-594 ◽  
Author(s):  
Anthony R. Magee ◽  
Ben-Erik van Wyk ◽  
Patricia M. Tilney ◽  
Stephen R. Downie
Keyword(s):  
Sequence Data ◽  
Molecular Data ◽  
Morphological Data ◽  
Data Sets ◽  
Monotypic Genus ◽  
North African ◽  
African Species ◽  
Dna Sequence Data ◽  
The North ◽  
Relationship Of

Generic circumscriptions and phylogenetic relationships of the Cape genera Capnophyllum, Dasispermum, and Sonderina are explored through parsimony and Bayesian inference analyses of nrDNA ITS and cpDNA rps16 intron sequences, morphology, and combined molecular and morphological data. The relationship of these genera with the North African genera Krubera and Stoibrax is also assessed. Analyses of both molecular data sets place Capnophyllum, Dasispermum, Sonderina, and the only southern African species of Stoibrax (S. capense) within the newly recognized Lefebvrea clade of tribe Tordylieae. Capnophyllum is strongly supported as monophyletic and is distantly related to Krubera. The monotypic genus Dasispermum and Stoibrax capense are embedded within a paraphyletic Sonderina. This complex is distantly related to the North African species of Stoibrax in tribe Apieae, in which the type species, Stoibrax dichotomum, occurs. Consequently, Dasispermum is expanded to include both Sonderina and Stoibrax capense. New combinations are formalized for Dasispermum capense, D. hispidum, D. humile, and D. tenue. An undescribed species from the Tanqua Karoo in South Africa is also closely related to Capnophyllum and the Dasispermum–Sonderina complex. The genus Scaraboides is described herein to accommodate the new species, S. manningii. This monotypic genus shares the dorsally compressed fruit and involute marginal wings with Capnophyllum, but is easily distinguished by its erect branching habit, green leaves, scabrous umbels, and fruit with indistinct median and lateral ribs, additional solitary vittae in each marginal wing, and parallel, closely spaced commissural vittae. Despite the marked fruit similarities with Capnophyllum, analyses of DNA sequence data place Scaraboides closer to the Dasispermum–Sonderina complex, with which it shares the erect habit, green (nonglaucous) leaves, and scabrous umbels.

A review of the fern genus Pellaea (Pteridaceae) in Australasia

2020 ◽  
Author(s):  
Patrick J. Brownsey ◽  
Daniel J. Ohlsen ◽  
Lara D. Shepherd ◽  
Whitney L. M. Bouma ◽  
Erin L. May ◽  
...  
Keyword(s):  
New Zealand ◽  
Chloroplast Dna ◽  
Dna Sequences ◽  
Sequence Data ◽  
Indigenous Species ◽  
Ploidy Levels ◽  
Dna Sequence Data ◽  
Australian Species ◽  
The Status ◽  
Chloroplast Dna Sequences

Five indigenous species of Pellaea in Australasia belong to section Platyloma. Their taxonomic history is outlined, morphological, cytological and genetic evidence for their recognition reviewed, and new morphological and chloroplast DNA-sequence data provided. Australian plants of P. falcata (R.Br.) Fée are diploid and have longer, narrower pinnae than do New Zealand plants previously referred to P. falcata, which are tetraploid. Evidence indicates that P. falcata does not occur in New Zealand, and that collections so-named are P. rotundifolia (G.Forst.) Hook. Chloroplast DNA sequences are uninformative in distinguishing Australian P. falcata from New Zealand P. rotundifolia, but show that Australian P. nana is distinct from both. Sequence data also show that Australian and New Zealand populations of P. calidirupium Brownsey & Lovis are closely related, and that Australian P. paradoxa (R.Br.) Hook. is distinct from other Australian species. Although P. falcata is diploid and P. rotundifolia tetraploid, P. calidirupium, P. nana (Hook.) Bostock and P. paradoxa each contain multiple ploidy levels. Diploid populations of Pellaea species are confined to Australia, and only tetraploids are known in New Zealand. Evolution of the group probably involved hybridisation, autoploidy, alloploidy, and possibly apomixis. Further investigation is required to resolve the status of populations from Mount Maroon, Queensland and the Kermadec Islands.

Cymbidium jiangchengense (Orchidaceae; Epidendroideae; Cymbidiinae), a new species from China: evidence from morphology and DNA sequences

Phytotaxa ◽  
2019 ◽  
Vol 408 (1) ◽  
pp. 77-84
Author(s):  
YING-LI PENG ◽  
ZHUANG ZHOU ◽  
SI-REN LAN ◽  
ZHONG-JIAN LIU
Keyword(s):  
Dna Sequences ◽  
Yunnan Province ◽  
Sequence Data ◽  
Detailed Comparison ◽  
Distinct Species ◽  
Molecular Study ◽  
Orchid Species ◽  
Dna Sequence Data ◽  
Pink Flower ◽  
A New Species

A new orchid species, Cymbidium jiangchengense, from Yunnan Province, China, is described and illustrated. Its distinctiveness is evaluated with morphology and molecular analyses. A detailed comparison between the newly discovered orchid and other members of Cymbidium was performed. The new plant was characterized by stem-like pseudobulbs, narrowly oblong leaves, coriaceous leaves with an acute apex, a 2-flowered inflorescence, a purplish pink flower, narrowly elliptic sepals, petals, a obovate-lanceolate lip with a cordate midlobe, a yellow central callus, and a disc with a trough shape longitudinal lamella from the base extending to the base of the midlobe and a lamellae apex inflated to form two calluses that are not confluent apically. These features distinguish this new orchid from all other known species of Cymbidium. A molecular study based on nuclear ribosomal ITS and plastid matK and rbcL DNA sequence data indicates that C. jiangchengense is a distinct species that sister to C. wadae and a member of section Eburnea, subgenus Cyperorchis.

Association of larvae and adults of Mexican species of Macrelmis (Coleoptera: Elmidae): a preliminary analysis using DNA sequences

Zootaxa ◽  
2012 ◽  
Vol 3361 (1) ◽  
pp. 56-62 ◽  
Author(s):  
JOSEFINA CURIEL ◽  
JUAN J. MORRONE
Keyword(s):  
Dna Sequence ◽  
Dna Sequences ◽  
Preliminary Analysis ◽  
Sequence Data ◽  
Strong Association ◽  
Life Stages ◽  
Adult Morphology ◽  
Dna Sequence Data ◽  
Mexican Species ◽  
Major Impediment

Insect life stages are known imperfectly in many cases, and classifications are usually based on adult morphology. This isunfortunate as information on other life stages may be useful for biomonitoring. The major impediment to using elmid(Coleoptera) larvae for freshwater biomonitoring is the lack of larval descriptions and illustrations. Reliable molecular proto-cols may be used to associate larvae and adults. After adults of seven species of Mexican Macrelmis were identified morpho-logically, seven larval specimens were associated to them based on two gene fragments: Cox1 and Cob. The phylogeneticanalysis allowed identifying the larval specimens as Macrelmis leonilae, M. scutellaris, M. species 7, M. species 10, and M.species 11. Two species based on adults associated uncertainly with one larva, and one larva did not match with any adult. Adult/larval association in elmids using DNA sequence data seems to be promising in terms of speed and reliability.

A newly recognised species that has been confused with the global polyphagous pest scale insect, Coccus hesperidum Linnaeus (Hemiptera: Coccomorpha: Coccidae)

Zootaxa ◽  
2017 ◽  
Vol 4320 (3) ◽  
pp. 571 ◽  
Author(s):  
YEN-PO LIN ◽  
HIROTAKA TANAKA ◽  
LYN G. COOK
Keyword(s):  
Adult Female ◽  
Dna Sequences ◽  
Sequence Data ◽  
Distinct Species ◽  
Scale Insect ◽  
Scale Insects ◽  
History Museum ◽  
Dna Sequence Data ◽  
Cryptic Species Complex ◽  
Coccus Hesperidum

Coccus hesperidum L. (Hemiptera: Coccomorpha: Coccidae), the type species of the soft scale genus Coccus L., the family Coccidae and the whole of the scale insects (Coccoidea), is a cosmopolitan plant pest. Using DNA sequence data and morphological comparisons, we determine that there is a distinct species that is morphologically very similar to C. hesperidum. Here, we describe the species as Coccus praetermissus Lin & Tanaka sp. n., based on adult female specimens from Australia, Malaysia and Thailand. The adult female of C. praetermissus sp. n. differs from C. hesperidum in having dorsal setae with bluntly rounded tips, whereas they are sharply pointed in C. hesperidum. A detailed description of the newly recognised species is provided, incorporating adult female morphology and DNA sequences from mitochondrial and nuclear loci. Our examination of slides from The Natural History Museum, London, and several Australian institutions indicates that C. praetermissus sp. n. has been confused sometimes with C. hesperidum s. s. These findings have potential relevance to plant biosecurity and quarantine because C. hesperidum is cosmopolitan whereas C. praetermissus sp. n., which is also polyphagous and the two species can share many host plants, currently appears to be more geographically restricted. Additionally, there is deep genetic divergence within C. praetermissus sp. n. that might indicate that it is a cryptic species complex, but wider geographic sampling is required to test this possibility. 

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