Viivi Virtanen

Microsatellite marker identification using genome screening and restriction-ligation

We have identified a fast and easy method for finding microsatellite markers that utilizes genome screening with inter-simple sequence repeat (ISSR) primers to detect microsatellite regions and to obtain sequence information flanking one side of the microsatellites and a restriction-ligation technique with a specific adaptor to allow sequence walking to obtain sequence information flanking the other side of the microsatellites. Two main alternatives of the method (with or without cloning) are presented. We successfully utilized the method when identifying microsatellite markers for 21 bryophyte species, three algal species, and for the raccoon dog. The proportion of polymorphic markers equaled 95%. We observed that microsatellites are commonly found within the sequenced ISSR amplification products (54% in the present study), in which case specific primers can be identified for the microsatellite without a further restriction-ligation step. It is evident that the DNA regions amplified by ISSR markers commonly represent microsatellite hotspots. We propose that the identified method and the knowledge of the common presence of additional microsatellite repeats within ISSR amplification products are especially attractive to researchers who conduct small-scale microsatellite identification, such as researchers in population genetics and conservation biology.

Genetic diversity in cyanobacterial symbionts of thalloid bryophytes

Two species of thalloid liverworts, Blasia pusilla and Cavicularia densa, form stable symbioses with nitrogen-fixing cyanobacteria. Both bryophytes promote the persistence of their cyanobacterial associations by producing specialized gemmae, which facilitate the simultaneous dispersal of the host and its nitrogen-fixing symbionts. Here the genetic diversity of cyanobacterial symbionts of Blasia and Cavicularia is examined. The results indicate that the primary symbionts of both bryophytes are closely related and belong to a specific group of symbiotic Nostoc strains. Related strains have previously been reported from hornworts and cycads, and from many terricolous cyanolichens. The evolutionary origins of all these symbioses may trace back to pre-Permian times. While the laboratory strain Nostoc punctiforme PCC 73102 has been widely used in experimental studies of bryophyte-Nostoc associations, sequence-identical cyanobionts have not yet been identified from thalloid liverworts in the field.

Genetic Composition of Bryophyte Populations Occupying Habitats Differing in the Level of Human Disturbance

By using microsatellite markers, we investigated the population genetic structure of three mainly clonally propagating bryophyte species—the hepatic Plagiochila asplenioides (L.) Dumort and the mosses Pleurozium schreberi (Willd. ex Brid.) Mitt. and Rhytidiadelphus squarrosus (Hedw.) Warnst—that occupy habitats differing in the level of human disturbance. Sampled populations, located in southern Finland, were classified as natural or disturbed. All species possessed a fair amount of genetic variation both within populations (mean diversities per population of , , and , respectively) and across populations (0.599, 0.618, and 0.400, respectively). On average, natural and disturbed populations possessed similar levels of genetic diversity. Differentiation levels (FST values of 0.356, 0.298, and 0.302, respectively) were significant but showed that there is some gene flow taking place. The Bayesian STRUCTURE analysis provided additional information on the population genetic structures. Although R. squarrosus was the species with the lowest level of genetic variation, its populations inhabiting urban, disturbed habitats tended to contain highly differentiated genotypes of different origins, which suggests that human-mediated dispersal is important in urban habitats. In addition, detailed analyses of the spatial genetic structure of R. squarrosus showed that at short distances (1 to <30 m) individuals are more closely related than expected, while at greater distances (30 to 500 m) kinship decreases with increasing distance. Thus, the rarity of sexual reproduction was visible in the spatial genetic structure within R. squarrosus populations, as aggregations of similar genotypes were found at short distances in populations otherwise showing isolation-by-distance effect.

The function of social support in engaging and disengaging experiences among post PhD researchers in STEM disciplines

ABSTRACT The post-doctoral phase is characterized by a high level of competition and even a risk of unemployment due to the increasing number of PhDs. This study explores the function of social support or lack of it in post PhD researchers’ engaging and disengaging experiences from the beginning of their careers as researchers. The data were collected from 40 post PhD researchers from STEM disciplines through semi-structured interviews and qualitatively content analysed. Receiving socio-emotional and informational support was perceived as highly significant for experienced engagement and disengagement, while instrumental support was rarely reported. Also a fourth form of social support, that is,. co-constructional support was identified. The results indicate that various forms of social support provide a significant mechanism that mediates post PhD researchers’ engagement and disengagement in their early careers.

What disengages doctoral students in the biological and environmental sciences from their doctoral studies

ABSTRACT This study explored the causes of student disengagement from their doctoral studies in the biological and environmental sciences. The data came from interviews of 40 doctoral students (male = 15, female = 25) and underwent qualitative analysis for content. Our results showed that doctoral studies provide multiple contexts for disengagement, such as the scholarly community and supervision, while doctoral students’ sense of distress, cynicism and inefficacy emerged as central components of disengagement. The study identified isolation, indifference, and lack of support and constructive feedback as sources of cynicism, while distress and inefficacy were more often related to failure or lack of progress in research. Our findings indicate that the source of disengagement can vary not only between individuals, but also between the academic activities at hand. Thus, while promoting an engaging doctoral experience, awareness of what typically triggers disengagement in the doctoral journey is vital.

From Functioning Communality to Hostile Behaviour: Students' and Teachers' Experiences of the Teacher-Student Relationship in the Academic Community.

Abstract Teacher support is an important factor affecting academic and social integration into the university. However, studies have been very scarce concerning both students’ and teachers’ experiences of their relationship in higher education. The purpose of this study is to examine students’ and teachers’ experiences of communality and interaction as well as the support given by teachers in the academic community. A total of 68 teachers and 104 students participated in this study by answering both Likert-scale and an open-ended question. The results show wide variation in both students’ and teachers’ experiences. The experiences varied from descriptions of a good and functional communality to a gap between teachers and students or even hostile behaviour towards students. Five main categories emerged from the data: (1) functioning interaction and communality, (2) good quality contacts between students and teachers, (3) variable experiences of interaction and communality, (4) low quality interaction and communality, and (5) dysfunctional contacts between students and teachers. The results indicate that teachers experience the support given to students more positively than the students. In addition, the results concerning the open-ended question also indicated that teachers experience the communality and interaction between teachers and students more positively than the students. More attention should be given to the teacher–student relationship at the higher education level. In addition, general skills such as ability to interact with others and social behaviour should be emphasised to a greater degree when recruiting staff.

Learning in Virtual Forest: a forest ecosystem in the web-based learning environment

Virtual Forest is a web-based, open-access learning environment about forests designed for primary-school pupils between the ages of 10 and 13 years. It is pedagogically designed to develop an understanding of ecology, to enhance conceptual development and to give a holistic view of forest ecosystems. Various learning tools, such as concept maps, activating questions, self-assessment, and other exercises, can be implemented to achieve these goals. The information is presented using the capabilities of hypermedia. The interactive systematic wholeness of nature is presented for the learners, within the context of a forest ecosystem and with examples of a few core ecological phenomena, including the cycling of matter, the flow of energy and population dynamics. The e-learning environment is designed to be used for blended learning, together with face-to-face instruction. Virtual Forest is about Finnish forests, but the pedagogical framework can be adapted for biological education in general.