Στην παρούσα ερευνητική εργασία μελετήθηκε η επίδραση της φύσης της πηγής άνθρακα και του διαλυμένου οξυγόνου στο διμορφισμό της ζύμης Yarrowia lipolytica. Για το σκοπό αυτό χρησιμοποιήθηκαν δύο διαφορετικά υποστρώματα, ένα υδρόφιλο (γλυκόζη) και ένα υδρόφοβο (ελαιόλαδο) και δύο διαφορετικοί ρυθμοί ανάδευσης (180 και 50 rpm) της καλλιέργειας για την εξασφάλιση διαφορετικών ποσοτήτων διαλυμένου οξυγόνου. Για τη διεξαγωγή των πειραμάτων χρησιμοποιήθηκε το στέλεχος Yarrowia lipolytica ACA-DC 50109, η καλλιέργεια του οποίου έγινε σε κωνικές φιάλες με ημι-συνθετικό θρεπτικό υλικό, περιοριστικό σε άζωτο, pH 6±0,5 και θερμοκρασία 28±1 oC, σε ανακινούμενο επωαστικό θάλαμο. Κατά τη διάρκεια της αύξησης του μικροοργανισμού και ανά τακτά χρονικά διαστήματα γινόταν καταμέτρηση της περιεκτικότητας της καλλιέργειας σε κύτταρα, παρατήρηση της μορφολογίας τους στο οπτικό μικροσκόπιο και υπολογισμός του ειδικού ρυθμού κατανάλωσης οξυγόνου σε αυτή. Η πειραματική διαδικασία ολοκληρώθηκε με τη λήψη εικόνων των διαφορετικών μορφών της Y. lipolytica από το Ηλεκτρονικό Μικροσκόπιο Σάρωσης. Το φαινόμενο του διμορφισμού, δηλαδή η ικανότητα του μικροοργανισμού να αναπτύσσεται είτε ως μεμονωμένα κύτταρα ζύμης είτε ως μυκήλιο, παρατηρήθηκε και με τη γλυκόζη και με το ελαιόλαδο ως πηγή άνθρακα, αλλά μόνο σε χαμηλό ρυθμό ανάδευσης της καλλιέργειας, όπου οι συνθήκες ήταν πρακτικά αναερόβιες. Η μορφολογία της Y. lipolytica ήταν παρόμοια και επί των δύο υποστρωμάτων, με τον αριθμό των ψευδομυκηλίων και αληθών μυκηλίων να είναι μεγαλύτερος στην περίπτωση του ελαιόλαδου. Γενικά, ο διμορφισμός ελέγχεται από το συνδυασμό διαφόρων περιβαλλοντικών παραγόντων, εκ των οποίων το διαλυμένο οξυγόνο φαίνεται να έχει ισχυρότερη επίδραση από αυτή της φύσης της πηγής άνθρακα, όπως συνάγεται από την παρούσα μελέτη. / In this MSc thesis, the effect of the nature of the carbon source and the concentration of dissolved oxygen on the dimorphism of the yeast Yarrowia lipolytica, was studied. For this purpose, a hydrophilic (glucose) and a hydrophobic (olive oil) substrate were used as well as two different shaking speeds (180 and 50 rpm) of the cultivation. Yarrowia lipolytica ACA-DC 50109 strain was cultivated in conical flasks, using semi-synthetic, nitrogen limited medium, at pH 6±0.5 and a temperature of 28±1 oC, in a shaking incubator. During growth cycle and at regular intervals, cell count, observation in an optical microscope and calculation of the specific oxygen uptake rate, were performed. Scanning Electron Microscopy (SEM) was also used to provide pictures of the different morphological forms of Y. lipolytica. Dimorphism, which refers to the ability of this microorganism to develop distinct cellular forms (yeast-like cells, mycelium), was observed in both glucose- and olive oil-based cultures but only at a low shaking speed, where practically anaerobic conditions prevailed. The morphology of Y. lipolytica was similar upon both substrates whereas more and larger true mycelia and pseudomycelia were noticed in the case of olive oil carbon source. Generally, dimorphism is influenced by the interplay of a variety of environmental stimuli, from which dissolved oxygen seems to have a stronger effect than the carbon source nature, as it is indicated in the present study.

We investigated possible sex differences in PRL secretory patterns and regulation by E$ sb2$ in gonadectomized Dorset x Leicester x Suffolk sheep kept under natural photoperiod (latitude 45$ sp circ 31 sp prime$). Patterns were assessed over 14 months in groups of 10 rams and ewes, half of which received E$ sb2$ replacement (Silastic implants) at the time of gonadectomy to maintain blood E$ sb2$ at ram breeding-season values. Mean monthly PRL level (based on two 3-h periods of blood sampling) was consistently elevated by E$ sb2$ in the ram (mean 19%), and during all but a few months in the spring and summer in the ewes (mean 90%). Sex differences in the mean PRL were most apparent for the E$ sb2$-treated sheep in August (rams 280 $ pm$ 54 ng/ml vs ewes 128 $ pm$ 18 ng/ml) and for the control sheep in November (rams 19 $ pm$ 5 ng/ml vs ewes 10 $ pm$ 2 ng/ml). Episodic PRL secretion (with 5-min sampling for 4 h) was assessed in every season. In all four groups, pulse amplitude and frequency and basal level were higher in summer than winter. E$ sb2$ treatment was associated with larger PRL pulses in both sexes in every season but summer, and with decreased (from 8.2 to 4.6 per 4 h) and increased (from 2.2 to 6.6 per 4 h) frequencies of pulses in rams in the spring and summer, respectively. The PRL response to TRH (two iv injections 50 ng/kg BW given 80 min apart) was also assessed in every season. Mean 40-min increases after injection were highest in spring and summer. E$ sb2$ treatment produced in both sexes a 2-3 fold larger increment 1 in every season, and increment 2 in specific seasons. Preinjection and increment values were positively correlated within animals of each group across seasons (r = 0.89 and 0.65). The Incr 2/lncr 1 ratio (mean 0.76 $ pm$ 0.10) was not affected by seasons or E$ sb2$, and did not denote a self priming effect of TRH. Diurnal patterns indicated that PRL mean levels during light and dark phases were not different from each other within

Sexual size dimorphism (SSD), or the difference in body size between males and females, is common in almost all taxa of animals and is usually assumed to be adaptive. Darwin's two main mechanisms for the evolution of SSD, sexual selection for larger males and fecundity selection for larger females, have often been demonstrated. However, males and females frequently share both genes and environment and more recent papers have noted that males and females must experience differences in lifetime selection on body size for SSD to be maintained. Over two generations I examined lifetime selection acting on adult body size (total length) in a common insect where females are larger than males, the waterstrider Aquarius remigis. Both fecundity selection for larger females and sexual selection for larger males are occurring in this species and both selective forces appear to target specific components of body size rather than total length; sexual selection targeting male genital length and fecundity selection targeting female abdomen length. While body size did not appear to influence adult prereproductive survival, longevity during the reproductive season was negatively related to body size for both sexes. When the opposing selection of reproductive success and reproductive longevity are combined, both males and females have an intermediate optimum body size. A remarkable result of this stabilizing selection was that the optimum size of males was smaller than that of females. I also examined the repeatability of reproductive success in both sexes and the trade-off between egg size and egg number. Finally, estimates of the quantitative genetic basis of the traits examined indicate that both male and female body size, and components of body size, are heritable and can respond to the selection detected. Components of body size in A. remigis are variable in both the degree and direction of sexual dimorphism and the genetic analysis indicates partial isolation of dimorphic and

Sexual dimorphism in life history traits may influence the distribution of the sexes,population sex ratios, the maintenance of sex in populations, and the evolutionarypotential of a species. In bryophytes, sexual dimorphism in traits related to growth andreproduction may be responsible for female-biased population sex ratios and a lack ofsexual reproduction. I examined the roles of natural selection in maintaining sexualdimorphism in the context of impacts on bryophyte population sex ratios, usingMarchantia inflexa as a model system. My studies included an assessment of amongpopulationvariation in habitat use by the sexes, comparison of phenotypes betweensingle-sex and both-sex populations, a field study of natural selection, and a comparisonof the influence of selection on asexual and sexual fitness components.The sexes of M. inflexa were sexually dimorphic in investment in growth, asexualand sexual reproduction. The sexes were spatially separated in populations, but thesexes overlapped in habitat use. Populations differed in growth, asexual reproductionrates, degrees of sexual dimorphism, and strength of among-trait correlations. Plantsfrom single-sex and both-sex populations differed in investment in growth and asexualreproduction, but the two population types showed the same degree of sexualdimorphism. Thus, local environment may be more influential than the presence of theopposite sex in maintaining sexual dimorphism.Selection on sexually dimorphic traits was both sex-specific and environmentallydependent. Between-sex correlations were not significant in the greenhouse but weresignificant in the field thus, evolution and expression of sexual dimorphism in nature maybe constrained by among-trait and between-sex correlations. Additionally, femalesincurred a cost of plasticity that males did not. Because there was a negative trade-offbetween sexual and asexual fitness, overall lifetime selection may result in a differentpicture of how the sexes experience selection. The combination of sex-specific andenvironment-dependent selection, and sex-specific costs to plasticity may not onlymaintain sexually dimorphic traits but also ensure the persistence of both sexes in apopulation.

The purpose of this study was to use geometric morphometrics (GM) to investigate the relationships between non-metric traits of the human hip bone: the greater sciatic notch (GSN), the ventral arc (VA), the subpubic contour (SPC), and the ischiopubic ramus ridge (IPRR), estimated skeletal sex, and shape. Fifty-nine undocumented left hip bone specimens were visually assessed for skeletal sex using recognized standards of sex estimation for the GSN (Buikstra and Ubelaker, 1994). The VA, SPC, and IPRR were assessed according to Klales et al., (2012). The Non-metric traits were scored on a five-scale scheme. Skeletal sex was classified as either male, possible male, indeterminate sex, possible female, or female. Three-dimensional computer models were created of the hip bones using the NextEngine 3D desktop surface scanner. Thirty landmarks were selected to represent the hip bone in three-dimensional shape for GM analysis. Twenty-seven of the selected landmarks were reliable according to suggested digitizing error measurements. The apex of the auricular surface, the arcurate eminence, and the anterior gluteal line were the least precise in the test for digitizing error. Geometric morphometric analysis of the computer models were performed using MorphoJ software. Principal component analysis identified the patterns of hip bone shape within the sex categories. A Procrustes ANOVA and a Spearman's correlation tested the significance between hip bone shape and estimated skeletal sex, and between hip bone shape and non-metric trait morphology. Patterns of hip bone shape in the ischium could not be identified by sex, however sex differences were identified in ischium size. Patterns of hip bone shape in the whole hip bone, segmented ilium and segmented pubis were distinguishable by larger sex groups (males = male and possible male categories; females = female and possible female categories). Shape patterns alluded to differences between females and possible females, however, shape patterns did not distinguish males from possible males. Individuals of indeterminate sex shared similar hip bone shapes as males and were therefore included in that larger sex group. Hip bone shape was also correlated with GSN, SPC, IPRR, and VA. However, the strength of the correlation differed between non-metric traits and certain components of hip bone shape. The GSN and SPC had the strongest correlation (p=<0.01) with the whole hip bone, the ilium and the pubis at distinguishing between larger male and female sex groups. The IPRR, and GSN had the strongest correlation (p=<0.01) with the pubis at distinguishing females and possible females. The results of the study suggest that non-metric traits can discern patterns of female shape better than patterns of male shape. Further research into discerning patterns of male hip bone shape and non-metric trait variation using GM is suggested. The results of the study also suggest that patterns of pubis shape might exist among females and could be identifiable using pubis non-metric trait scores. This result lends credence to the practice of estimating sex on a five-scale gradient rather than on a male/female dichotomous division, in order to capture the morphological variation of female hip bone better. / Graduate / 0327 / 0339 / heatherisobelrobertson@gmail.com

The socio-ecological correlates of cross-cultural variation in lactase persistence, sexual dimorphism in stature, and wealth inheritance in Africa were investigated, using phylogenetic comparative methods to control for the non-independence of populations (Galton's problem). Felsenstein's method of comparative analysis using independent contrasts, and Pagel's phylogenetic maximum likelihood model, were used. Genetic and linguistic trees were used as models of the past relationships among populations. Lactase persistence was found to be associated with pastoralism but not with solar intensity or aridity. This is consistent with the hypothesis that high lactose digestion capacity in adults is an adaptation to dairying. This result does not support the hypotheses that low solar radiation at high latitudes and aridity are additional selective pressures for lactase persistence. Cross-cultural variation in stature was associated with women's work. Women are taller, relative to men, in societies where women contribute more to subsistence. In Africa, patrilineal wealth inheritance is associated with pastoralism and polygyny. Patrilineal wealth inheritance is adaptive if inherited wealth benefits sons more than daughters, which is probably the case in both polygynous and pastoralist societies. It is hypothesised that matrilineal inheritance arises from wealth inheritance to daughters. Inheritance to daughters is adaptive if the additional benefits of wealth inheritance to sons do not outweigh the risk of paternity uncertainty of sons' offspring. The transmission, between populations, of those bio-cultural traits in the comparative analyses was also investigated. The association between each trait in a population, and that trait in the population's phylogenetic sister-group and nearest geographical neighbour(s) were compared using regression. The majority of traits were found to be associated with phylogeny. Some traits showed an additional association with geographical neighbours. Vertical transmission, from `mother' to `daughter' populations, appears to be more important than geographical diffusion between neighbouring populations, for the majority of the traits tested here.

Successional changes in a habitat may result in bottlenecks where few individuals in a population survive. During such events, changes in the genetic architecture of traits are predicted to occur as is subsequent inbreeding depression. In two literature reviews, I document that, (1) dominance variance increases in traits that are subject to strong selection and, (2) inbreeding depression is substantially higher in the wild as compared to captive populations. In addition to these changes, successional pressures may also result in the evolution of morphologies that allow organisms to avoid unfavourable conditions. A common dimorphism in insects is wing dimorphism, in which the macropterous morph is long-winged (LW), has functional flight muscles and is flight-capable while the micropterous morph (SW) has reduced wings and cannot fly. Due to the energy required to maintain the flight apparatus, macropterous individuals are predicted to have less energy available for reproduction. Trade-offs to macroptery have been documented in female insects. Gryllus firmus is a wing-dimorphic cricket of the southeastern USA. Although there are well established trade-offs between macroptery and reproduction in female crickets, no trade-offs have been demonstrated in male crickets. The prediction is that LW males, because they have to expend energy to maintain the flight apparatus, will call less and therefore attract fewer females than SW males. To be evolutionarily important, the traits involved in the trade-off; call duration, wing morph, wing muscle condition and lipid weight should have significant heritabilities and be genetically correlated. I found that SW males attracted significantly more females than LW males (mean % = 70% (SW) 30% (LW)). A significant difference in time spent calling was found between SW and LW males and as the difference in calling time between males increased, the likelihood of a female choosing the longer-calling male also increased. All the traits ha

Thesis (Ph.D.) - University of St Andrews, May 2007.

Thesis (Ph. D.)--University of Washington, 1997. / Vita. Includes bibliographical references (leaves [76]-86).

Thesis (M.S.)--Ohio State University, 2005. / Includes bibliographical references (leaves 86-98). Available online via OhioLINK's ETD Center