The population structure of a lichen, Thamnolia subuliformis and a moss, Dicranum elongatum, was examined in northeastern regions of Wapusk National Park. With the use of microsatellite molecular markers, it was reported that the sterile lichen had a level of variation similar to that of a sexually reproducing species. The variation reported for the moss, where sporophytes were not encountered, supported subdivided populations. It was concluded that these species have the genetic resources necessary to adapt to changing environmental conditions. / February 2007

The population structure of a lichen, Thamnolia subuliformis and a moss, Dicranum elongatum, was examined in northeastern regions of Wapusk National Park. With the use of microsatellite molecular markers, it was reported that the sterile lichen had a level of variation similar to that of a sexually reproducing species. The variation reported for the moss, where sporophytes were not encountered, supported subdivided populations. It was concluded that these species have the genetic resources necessary to adapt to changing environmental conditions.

The population structure of a lichen, Thamnolia subuliformis and a moss, Dicranum elongatum, was examined in northeastern regions of Wapusk National Park. With the use of microsatellite molecular markers, it was reported that the sterile lichen had a level of variation similar to that of a sexually reproducing species. The variation reported for the moss, where sporophytes were not encountered, supported subdivided populations. It was concluded that these species have the genetic resources necessary to adapt to changing environmental conditions.

L’analyse et l’interprétation d’´echantillons constitu´es de mélanges d’ADN de plusieurs individus est un défi majeur en science forensique. Lorsqu’un expert de la police scientifique a affaire à un mélange d’ADN il doit répondre à deux questions: d’abord, “combien de contributeurs y a-t-il dans ce mélange ?”et puis, “quels sont les génotypes des individus impliqués ?” Le typage seul de cet ADN ne permet pas toujours de r´epondre `a ces questions. En effet leproblème est posé d`es lors que plus de deux allèles sont observées à un locus donné, plusieurscombinaisons génotypiques sont alors `a envisager et il est impossible de déterminer avec certitudele nombre d’individus qui ont contribué au m´elange. De plus, la présence d’anomalies liées àl’analyse de marqueurs g´en´etiques, comme la contamination ou la perte d’all`eles (“drop-out”),peut davantage compliquer l’analyse.Les nombreux d´eveloppements statistiques d´edi´es `a ces probl´ematiques n’ont pas eu le succ`esescompt´e dans la communaut´e forensique, essentiellement, parce que ces m´ethodes n’ont pas ´et´evalid´ees. Or sans cette validation, les experts de la police scientifique ne peuvent exploiter cesm´ethodes sur des m´elanges issus d’affaires en cours d’investigation.Avant d’ˆetre valid´ees, ces m´ethodes doivent passer par une rigoureuse ´etape d’´evaluation.Cette derni`ere soul`eve deux questions: d’abord, la question de la m´ethodologie `a adopter, puis,celle des outils `a d´eployer. Dans cette th`ese, nous tentons de r´epondre aux deux questions.D’abord, nous menons des ´etudes d’´evaluation sur des m´ethodes d´edi´ees `a deux questions cl´es: i)l’estimation du nombre de contributeurs `a un m´elange d’ADN et ii) l’estimation des probabilit´esde “drop-out”. En second lieu, nous proposons un logiciel “open-source” qui offre un certainnombre de fonctionnalit´es permettant de faciliter l’´evaluation de m´ethodes statistiques d´edi´eesaux m´elanges d’ADN.Cette thèse a pour but d’apporter une r´eponse concr`ete aux experts de la police scientifiqueen leur fournissant `a la fois une d´emarche m´ethodologique pour l’´evaluation de m´ethodes, et lapossibilit´e d’analyser la sensibilit´e de leurs r´esultats au travers d’un outil informatique en libreacc`es. / Analysis of forensic DNA mixtures recovered from crime scenes is one of the most challengingtasks in forensic science. DNA mixture raise two main questions: “how many contributors arethere” and “what are the genotypes of the contributing individuals?” The genetic characterizationalone of such samples does not always answer these questions. In fact, whenever more thantwo alleles are observed at a given locus, several distinct genotypic combinations are plausiblefor the unknown contributors to the sample, and it is not possible to determine the number ofthese contributors with absolute certainty. Besides, the presence of anomalies related to DNAtyping techniques, such as contamination or allele loss (drop-out), can further complicate theanalysis.Numerous statistical developments facilitating DNA mixtures interpretation were proposed,but they did not receive the expected success in the forensic community. The main explanationfor this is that these methods are not validated for forensic casework.In order to achieve this validation criterion, the methods must undergo a rigorous evaluationstep. The latter raises two questions: i) how methods should be evaluated? and ii) whattools can be used to conduct evaluation studies? In this thesis we attempt to answer bothquestions. First, we evaluate methods dedicated to two key issues, the estimation of the numberof contributors to DNA mixtures and the estimation of drop-out probabilities. Second, wepropose an “open-source” software that offers a number of functionalities dedicated to facilitatingmethod evaluation through the simulation of data commonly encountered in forensic settings.This thesis aims to provide a concrete answer to the issues raised by forensic DNA mixtures,by providing a methodology for method evaluation and by offering necessary tools to enablemethod evaluation.

This thesis investigates the molecular evolutionary and macroevolutionary consequences of flight loss in insects. Chapter 2 tests the hypothesis that flightless groups have smaller effective population sizes than related flighted groups, expected to result in a consistent pattern of increased non-synonymous to synonymous ratios in flightless lineages due to the greater effect of genetic drift in smaller populations. Chapter 3 tests the hypothesis that reduced dispersal and species-level traits such as range size associated with flightlessness increase extinction rates, which over the long term will counteract increased speciation rates in flightless lineages, leading to lower net diversification. The wide-spread loss of flight in insects has led to increased molecular evolutionary rates and is associated with decreased long-term net diversification. I demonstrate that the fundamental trait of dispersal ability has shaped two forms of diversity—molecular and species—in the largest group of animals, and that microevolutionary and macroevolutionary patterns do not necessarily mirror each other. / Generously funded by NSERC with a Canada Graduate Scholarship and the Government of Ontario with an Ontario Graduate Scholarship to T. Fatima Mitterboeck; NSERC with a Discovery Grant to Dr. Sarah J. Adamowicz