No description available.

No description available.

The phylogenetic relationships of the subfamily Dolichopodinae were investigated based on the examination of over 340 species from all zoogeographic regions. Sixty-five exemplar species were included in cladistic analysis based on 74 morphological characters of adult specimens. Twenty genera are recognized in the Dolichopodinae: Allohercostomus Yang, Saigusa and Masunaga, Anasyntormon Parent, Argyrochlamys Lamb, Cheiromyia Dyte, Dolichopus Latreille, Ethiromyia gen. nov., Gymnopternus Loew, Hercostomus Loew, Metaparaclius Becker, Muscidideicus Becker, Ortochile Latreille, Paraclius Loew, Parahercostomus Yang, Saigusa and Masunaga, Pelastoneurus Loew, Platyopsis Parent, Poecilobothrus Mik, Prohercostomus Grichanov, Stenopygium Becker, Sybistroma Meigen, and Tachytrechus Stannius. Eleven genera are newly synonymized: Halaiba Parent (= Argyrochlamys Lamb); Lichtwardtia Enderlein (= Dolichopus Latreille); Phalacrosoma Becker (= Hercostomus Loew); Steleopyga Grootaert and Meuffels (= Hercostomus Loew); Proarchus Aldrich (= Pelastoneurus Loew); Sarcionus Aldrich (= Pelastoneurus Loew); Pterostylus Mik (= Poecilobothrus Mik); Ludovicius Rondani (= Sybistroma Meigen); Nodicornis Rondani (= Sybistroma Meigen); Gonioneurum Becker (= Tachytrechus Stannius); Syntomoneurum Becker (= Tachytrechus Stannius). Eighty-one new generic combinations are established and one new name is proposed for a secondary homonym. Four genera that were sometimes included in the subfamily are excluded, namely Colobocerus Parent, Katangaia Parent, Pseudohercostomus Stackelberg and Vetimicrotes Dyte. A key to the world genera of Dolichopodinae is provided. The Tachytrechus alatus species group (formerly the genus Syntomoneurum) is revised. This species group includes five Neotropical species, all of which are redescribed. A key to the species of the T. alatus species group is provided. The new genus Ethiromyia is also described, including two Nearctic and one Palaearctic spec

Common ancestry prevents scientists from using traditional statistical tests in dimensional comparisons that span entire clades. Data in these cases are non-independent, so a variety of special statistical methods have been developed specifically for phylogenetic comparative analyses. A phylogenetic least squares method was used to re-examine four published datasets detailing structural correlates of eyes while factoring in the different ways the phylogeny was expected to affect the covariance in trait values. All analyses were carried out in a strict phylogenetic context, using published time-calibrated phylogenies and the statistical platform R. Specifically, Pagel’s lambda was used to determine how much of an influence phylogeny had on each pair of traits. In all tested soft and hard tissue correlations, the phylogeny of the species slightly altered the trend lines of the measurements, compared to lines that did not take phylogenetic relationship into consideration. These results do not contradict previous results, but further work needs to be done to determine the implications that significant phylogenetic signal has on subsequent analyses. Future studies should account for phylogenetic relationships which have been shown to influence the relationship between traits.

Most of the detailed studies on periphyton in New Zealand rivers and streams have focused on diatoms. Despite the recent rise of interest in potentially toxic cyanobacterial mats, knowledge of the diversity and ecology of these and other macroscopic growth forms is incomplete. A taxonomic survey was made on periphytic cyanobacteria at 100 locations along Kaituna River and a 1st to 3rd order tributary stream. Samples were taken from runs, riffles and pools in shaded and unshaded locations and from varied substrata from January to December 2011. Descriptions were made of all macroscopic growths. Fifty-six morphospecies were identified of which 29 are new records for New Zealand. Crust components were the most diverse with 23 morphospecies followed by mats (16), gelatinous colonies (5) and epiphytes (7). Five appeared only after growth in enrichment cultures. Twelve morphospecies were isolated into cultures for use in polyphasic assessment. In 16S rDNA phylogenies, Placoma regulare and Heteroleibleinia fontana did not cluster with other members of their traditional families. Nostoc sp. 2 was positioned distant from other Nostoc strains. Comparison of 16S – 23S rRNA internal transcribed spacer compositions for seven mat-forming oscillatorialean morphospecies confirmed their recognition as distinct morphospecies. Amplified fragment length polymorphisms were used to investigate genetic diversity of Nostoc verrucosum in relation to dispersal. This indicated that local dispersal is dominant while cross-catchment dispersal is probably infrequent. Light intensity, substratum type and water conductivity were significant factors influencing spatial patterns of distribution. Higher diversity of crusts, mats and gelatinous colonies was recorded in unshaded locations. Mats and gelatinous colonies were most diverse in Kaituna River and crusts in second to third order streams. Morphospecies in water with high conductivity were restricted to those locations. Spates had a major effect on temporal distribution. An increase in frequency and intensity of spates in spring and winter resulted in greater reduction in cover. Smaller spates caused partial removal followed by rapid regrowth within a week. Major spates caused complete removal of visible cover with re-colonization occurring within three to four weeks. This study has provided a first detailed account of cyanobacterial diversity and ecology in a New Zealand catchment. It provides a basis for long-term monitoring at this site of the effects of changes in climate and in human activities in the catchment.

No description available.

A phylogenetic analysis of the tribe Azeliini (Muscidae) was conducted, as well as a revision and phylogenetic analysis of the genus Thricops Rondani. Forty-four valid species and two subspecies of Thricops were recognised, including six species new to science. All species of this genus have been redescribed and illustrated, and a key to the world fauna is presented. An exemplar-based phylogenetic analysis of Thricops was conducted using three different sources of data: morphological characters of the adults, nucleotide sequence from the nuclear gene white and nucleotide sequence from the subunits I and II of the mitochondrial gene cytochrome c oxidase. The monophyly of Thricops sensu lato was supported by the analysis of all individual and combined data sets. Combination of data sets increased resolution for the smaller taxon sets, where there was little missing data. The mitochondrial sequence generally provided finer resolution and better branch support than white. The phylogenetic analysis of the Azeliini was based on adult morphological characters of 32 exemplar species representing ten genera. The monophyly of the Azeliini was well supported by eight apomorphic characters. The genus Australophyra Malloch was removed from synonymy with Hydrotaea R.-D. and reinstated, Megophyra Emden was synonymized with Neohydrotaea Malloch, and Crucianella Xue & Mang was synonymized with Xestomyia Stein. A number of new combinations resulted from these new synonymies. A generic key to the Azeliini was presented, and all genera redescribed according to the new limits defined in this study.

The study of phylogeny, i.e. the evolutionary history of species, is a central problem in biology and a key for understanding characteristics of contemporary species. Many problems in this area can be formulated as combinatorial optimisation problems which makes it particularly interesting for computer scientists. The reconstruction of the phylogeny of species can be based on various kinds of data, e.g. morphological properties or characteristics of the genetic information of the species. Maximum parsimony is a popular and widely used method for phylogenetic reconstruction aiming for an explanation of the observed data requiring the least evolutionary changes. A certain property of the genetic information gained much interest for the reconstruction of phylogeny in recent time: the organisation of the genomes of species, i.e. the arrangement of the genes on the chromosomes. But the idea to reconstruct phylogenetic information from gene arrangements has a long history. In Dobzhansky and Sturtevant (1938) it was already pointed out that “a comparison of the different gene arrangements in the same chromosome may, in certain cases, throw light on the historical relationships of these structures, and consequently on the history of the species as a whole”. This kind of data is promising for the study of deep evolutionary relationships because gene arrangements are believed to evolve slowly (Rokas and Holland, 2000). This seems to be the case especially for mitochondrial genomes which are available for a wide range of species (Boore, 1999). The development of methods for the reconstruction of phylogeny from gene arrangement data has made considerable progress during the last years. Prominent examples are the computation of parsimonious evolutionary scenarios, i.e. a shortest sequence of rearrangements transforming one arrangement of genes into another or the length of such a minimal scenario (Hannenhalli and Pevzner, 1995b; Sankoff, 1992; Watterson et al., 1982); the reconstruction of parsimonious phylogenetic trees from gene arrangement data (Bader et al., 2008; Bernt et al., 2007b; Bourque and Pevzner, 2002; Moret et al., 2002a); or the computation of the similarities of gene arrangements (Bergeron et al., 2008a; Heber et al., 2009). 1 1 Introduction The central theme of this work is to provide efficient algorithms for modified versions of fundamental genome rearrangement problems using more plausible rearrangement models. Two types of modified rearrangement models are explored. The first type is to restrict the set of allowed rearrangements as follows. It can be observed that certain groups of genes are preserved during evolution. This may be caused by functional constraints which prevented the destruction (Lathe et al., 2000; Sémon and Duret, 2006; Xie et al., 2003), certain properties of the rearrangements which shaped the gene orders (Eisen et al., 2000; Sankoff, 2002; Tillier and Collins, 2000), or just because no destructive rearrangement happened since the speciation of the gene orders. It can be assumed that gene groups, found in all studied gene orders, are not acquired independently. Accordingly, these gene groups should be preserved in plausible reconstructions of the course of evolution, in particular the gene groups should be present in the reconstructed putative ancestral gene orders. This can be achieved by restricting the set of rearrangements, which are allowed for the reconstruction, to those which preserve the gene groups of the given gene orders. Since it is difficult to determine functionally what a gene group is, it has been proposed to consider common combinatorial structures of the gene orders as gene groups (Marcotte et al., 1999; Overbeek et al., 1999). The second considered modification of the rearrangement model is extending the set of allowed rearrangement types. Different types of rearrangement operations have shuffled the gene orders during evolution. It should be attempted to use the same set of rearrangement operations for the reconstruction otherwise distorted or even wrong phylogenetic conclusions may be obtained in the worst case. Both possibilities have been considered for certain rearrangement problems before. Restricted sets of allowed rearrangements have been used successfully for the computation of parsimonious rearrangement scenarios consisting of inversions only where the gene groups are identified as common intervals (Bérard et al., 2007; Figeac and Varré, 2004). Extending the set of allowed rearrangement operations is a delicate task. On the one hand it is unknown which rearrangements have to be regarded because this is part of the phylogeny to be discovered. On the other hand, efficient exact rearrangement methods including several operations are still rare, in particular when transpositions should be included. For example, the problem to compute shortest rearrangement scenarios including transpositions is still of unknown computational complexity. Currently, only efficient approximation algorithms are known (e.g. Bader and Ohlebusch, 2007; Elias and Hartman, 2006). Two problems have been studied with respect to one or even both of these possibilities in the scope of this work. The first one is the inversion median problem. Given the gene orders of some taxa, this problem asks for potential ancestral gene orders such that the corresponding inversion scenario is parsimonious, i.e. has a minimum length. Solving this problem is an essential component 2 of algorithms for computing phylogenetic trees from gene arrangements (Bourque and Pevzner, 2002; Moret et al., 2002a, 2001). The unconstrained inversion median problem is NP-hard (Caprara, 2003). In Chapter 3 the inversion median problem is studied under the additional constraint to preserve gene groups of the input gene orders. Common intervals, i.e. sets of genes that appear consecutively in the gene orders, are used for modelling gene groups. The problem of finding such ancestral gene orders is called the preserving inversion median problem. Already the problem of finding a shortest inversion scenario for two gene orders is NP-hard (Figeac and Varré, 2004). Mitochondrial gene orders are a rich source for phylogenetic investigations because they are known for more than 1 000 species. Four rearrangement operations are reported at least in the literature to be relevant for the study of mitochondrial gene order evolution (Boore, 1999): That is inversions, transpositions, inverse transpositions, and tandem duplication random loss (TDRL). Efficient methods for a plausible reconstruction of genome rearrangements for mitochondrial gene orders using all four operations are presented in Chapter 4. An important rearrangement operation, in particular for the study of mitochondrial gene orders, is the tandem duplication random loss operation (e.g. Boore, 2000; Mauro et al., 2006). This rearrangement duplicates a part of a gene order followed by the random loss of one of the redundant copies of each gene. The gene order is rearranged depending on which copy is lost. This rearrangement should be regarded for reconstructing phylogeny from gene order data. But the properties of this rearrangement operation have rarely been studied (Bouvel and Rossin, 2009; Chaudhuri et al., 2006). The combinatorial properties of the TDRL operation are studied in Chapter 5. The enumeration and counting of sorting TDRLs, that is TDRL operations reducing the distance, is studied in particular. Closed formulas for computing the number of sorting TDRLs and methods for the enumeration are presented. Furthermore, TDRLs are one of the operations considered in Chapter 4. An interesting property of this rearrangement, distinguishing it from other rearrangements, is its asymmetry. That is the effects of a single TDRL can (in the most cases) not be reversed with a single TDRL. The use of this property for phylogeny reconstruction is studied in Section 4.3. This thesis is structured as follows. The existing approaches obeying similar types of modified rearrangement models as well as important concepts and computational methods to related problems are reviewed in Chapter 2. The combinatorial structures of gene orders that have been proposed for identifying gene groups, in particular common intervals, as well as the computational approaches for their computation are reviewed in Section 2.2. Approaches for computing parsimonious pairwise rearrangement scenarios are outlined in Section 2.3. Methods for the computation genome rearrangement scenarios obeying biologically motivated constraints, as introduced above, are detailed in Section 2.4. The approaches for the inversion median problem are covered in Section 2.5. Methods for the reconstruction of phylogenetic trees from gene arrangement data are briefly outlined in Section 2.6.3 1 Introduction Chapter 3 introduces the new algorithms CIP, ECIP, and TCIP for solving the preserving inversion median problem. The efficiency of the algorithm is empirically studied for simulated as well as mitochondrial data. The description of algorithms CIP and ECIP is based on Bernt et al. (2006b). TCIP has been described in Bernt et al. (2007a, 2008b). But the theoretical foundation of TCIP is extended significantly within this work in order to allow for more than three input permutations. Gene order rearrangement methods that have been developed for the reconstruction of the phylogeny of mitochondrial gene orders are presented in the fourth chapter. The presented algorithm CREx computes rearrangement scenarios for pairs of gene orders. CREx regards the four types of rearrangement operations which are important for mitochondrial gene orders. Based on CREx the algorithm TreeREx for assigning rearrangement events to a given tree is developed. The quality of the CREx reconstructions is analysed in a large empirical study for simulated gene orders. The results of TreeREx are analysed for several mitochondrial data sets. Algorithms CREx and TreeREx have been published in Bernt et al. (2008a, 2007c). The analysis of the mitochondrial gene orders of Echinodermata was included in Perseke et al. (2008). Additionally, a new and simple method is presented to explore the potential of the CREx method. The new method is applied to the complete mitochondrial data set. The problem of enumerating and counting sorting TDRLs is studied in Chapter 5. The theoretical results are covered to a large extent by Bernt et al. (2009b). The missing combinatorial explanation for some of the presented formulas is given here for the first time. Therefor, a new method for the enumeration and counting of sorting TDRLs has been developed (Bernt et al., 2009a).

Thesis (Ph. D.)--University of Texas at Dallas, 2007. / Includes vita. Includes bibliographical references (leaves 114-125)

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2007. / Includes bibliographical references. Also available in electronic version.