title: Population Genetics and Photobiont Selectivity in Antarctic Lichens

authors: Burgess-Jones, Tracey

subjects: Lichen

abstract: This thesis examines population genetic structure and migration indices of an Antarctic endemic lichen Buellia frigida as well as algal selectivity of the lichens Buellia frigida, Umbilicaria aprina and Umbilicaria decussata in the Ross Sea Region of Antarctica. My aim was to determine where current populations may have originated (i.e. ancient or recent introductions to Antarctica) and if the level of algal selectivity potentially affects colonisation. 
Chapter 2 reviews historical climate change in Antarctica, particularly in the Ross Sea Region, and introduces the basic characteristics of lichens. It also outlines how molecular analyses of lichen can aid in determining the genetic structure of populations and add to the growing data set which highlights sites in the Ross Sea Region (e.g. Dry Valleys) as glacial refugia. 
To examine population differentiation between populations in this region it was necessary to develop polymorphic markers capable of delineating individuals.  Chapter 3 focuses on the development of five microsatellite markers for this purpose. The initial data for these microsatellites suggested they were suitable for individual genotyping and characterization of B. frigida population structure being mycobiont specific with a high degree of polymorphism. A method of decreasing inhibiting factors present in lichen cells is also provided.
In Chapter 4 regional genetic differentiation was revealed by an analysis using microsatellite markers developed in Chapter 3 over 11 populations in five regions of the Ross Sea Region. The identification of three populations with high allelic richness and sites of high dispersal indicated three regions as putative refugia (Terra Nova Bay, Dry Valleys and Beardmore Glacier). Terra Nova Bay has not previously been highlighted putatively as refugia. Limited mixing between adjacent geographical areas (such as the Dry Valleys and Ross Island) was identified, with migration likely to be influenced by wind currents.
The photobionts of the lichens Buellia frigida, Umbilicaria aprina and Umbilicaria decussata were examined using ITS rDNA sequence analysis in chapter 5. This identified that over a latitudinal gradient of roughly 10˚, there was a single haplotype present in the majority (>95%) of samples. This haplotype was nearly identical to haplotypes from as far afield as Svalbard showing a consistency in photobiont selection over a very wide geographical range and may be micro-climate specific. Other haplotypes present were specific to single geographical areas, and mutation may play the major role in this. 
Collectively, these findings suggest that despite potentially high dispersal of propagules, populations of lichen species in the Ross Dependency show differentiation among locations and are potentially limited in their dispersal to different habitats. This may be the result of high selectivity for the photobiont. I conclude that lichen populations in the Ross Sea Region have originated from ancient, refugial populations rather than being populated via recent dispersal from northern continents. Dispersal within this region is likely to be restricted by ice-covered areas and relichenisation is potentially limited to particular photobiont strains which are suited to the micro-climatic conditions found in this region. In order to minimise the consequences of anthropological disturbance, we recommend the continued protection of areas (e.g. Dry Valleys) housing high lichen and photobiont diversity.

text: Population Genetics and Photobiont Selectivity in Antarctic Lichens This thesis examines population genetic structure and migration indices of an Antarctic endemic lichen Buellia frigida as well as algal selectivity of the lichens Buellia frigida, Umbilicaria aprina and Umbilicaria decussata in the Ross Sea Region of Antarctica. My aim was to determine where current populations may have originated (i.e. ancient or recent introductions to Antarctica) and if the level of algal selectivity potentially affects colonisation. 
Chapter 2 reviews historical climate change in Antarctica, particularly in the Ross Sea Region, and introduces the basic characteristics of lichens. It also outlines how molecular analyses of lichen can aid in determining the genetic structure of populations and add to the growing data set which highlights sites in the Ross Sea Region (e.g. Dry Valleys) as glacial refugia. 
To examine population differentiation between populations in this region it was necessary to develop polymorphic markers capable of delineating individuals.  Chapter 3 focuses on the development of five microsatellite markers for this purpose. The initial data for these microsatellites suggested they were suitable for individual genotyping and characterization of B. frigida population structure being mycobiont specific with a high degree of polymorphism. A method of decreasing inhibiting factors present in lichen cells is also provided.
In Chapter 4 regional genetic differentiation was revealed by an analysis using microsatellite markers developed in Chapter 3 over 11 populations in five regions of the Ross Sea Region. The identification of three populations with high allelic richness and sites of high dispersal indicated three regions as putative refugia (Terra Nova Bay, Dry Valleys and Beardmore Glacier). Terra Nova Bay has not previously been highlighted putatively as refugia. Limited mixing between adjacent geographical areas (such as the Dry Valleys and Ross Island) was identified, with migration likely to be influenced by wind currents.
The photobionts of the lichens Buellia frigida, Umbilicaria aprina and Umbilicaria decussata were examined using ITS rDNA sequence analysis in chapter 5. This identified that over a latitudinal gradient of roughly 10˚, there was a single haplotype present in the majority (>95%) of samples. This haplotype was nearly identical to haplotypes from as far afield as Svalbard showing a consistency in photobiont selection over a very wide geographical range and may be micro-climate specific. Other haplotypes present were specific to single geographical areas, and mutation may play the major role in this. 
Collectively, these findings suggest that despite potentially high dispersal of propagules, populations of lichen species in the Ross Dependency show differentiation among locations and are potentially limited in their dispersal to different habitats. This may be the result of high selectivity for the photobiont. I conclude that lichen populations in the Ross Sea Region have originated from ancient, refugial populations rather than being populated via recent dispersal from northern continents. Dispersal within this region is likely to be restricted by ice-covered areas and relichenisation is potentially limited to particular photobiont strains which are suited to the micro-climatic conditions found in this region. In order to minimise the consequences of anthropological disturbance, we recommend the continued protection of areas (e.g. Dry Valleys) housing high lichen and photobiont diversity.

year: 2013

title: Fictions and the scope of the artist in the novels of Janet Frame

authors: MacLennan, Carol H. G.

abstract: Art and the initiation of the artist into the skills of her craft, along with the fiction making habits of all human beings, are identified in this study as major concerns in Janet Frame’s novels. Time and change, rituals, regulations, popular music, war and love all have in common the fact that they are fictions created by human beings to order and control their lives. 

People construct fictions intentionally and otherwise to give substance to their short, fragmented existence and to try to explain their place in the universe. Janet Frame’s novels address themselves to the transience and uncertainty of human life confined as it is by the rigid boundaries of birth and death. 

This thesis indicates how the myth-making habits of ancient peoples have been adapted to help modern mankind cope with its precarious situation balanced between the inner abstract world of the mind and the outer physical universe. Added to this uneasy existence, composed of fleeting thoughts and acts which vanish as they are performed, is awareness of life’s impermanence, painfully emphasised by our inevitable mortality. Frame’s work acknowledges and attempts to moderate these facts.

text: Fictions and the scope of the artist in the novels of Janet Frame Art and the initiation of the artist into the skills of her craft, along with the fiction making habits of all human beings, are identified in this study as major concerns in Janet Frame’s novels. Time and change, rituals, regulations, popular music, war and love all have in common the fact that they are fictions created by human beings to order and control their lives. 

People construct fictions intentionally and otherwise to give substance to their short, fragmented existence and to try to explain their place in the universe. Janet Frame’s novels address themselves to the transience and uncertainty of human life confined as it is by the rigid boundaries of birth and death. 

This thesis indicates how the myth-making habits of ancient peoples have been adapted to help modern mankind cope with its precarious situation balanced between the inner abstract world of the mind and the outer physical universe. Added to this uneasy existence, composed of fleeting thoughts and acts which vanish as they are performed, is awareness of life’s impermanence, painfully emphasised by our inevitable mortality. Frame’s work acknowledges and attempts to moderate these facts.

year: 1986

title: Computational thinking for young indigenous learners in New Zealand

authors: Fox-Turnbull, Wendy

subjects: authentic technological practice

abstract: This article presents the findings from a study aimed to investigate how the computational thinking aspect of digital technologies can be embedded authentically into students’ technological practice. The project explored teaching and learning computational thinking in context and particularly focus on technological needs and practice for young Māori learners.
There is recognition internationally about the need for digital technologies within the curriculum. Computational thinking is a critical component of this and is defined as an approach to problem-solving, designing computer systems, and understanding related human behaviours, while drawing on fundamental ideas of computing. Therefore, it is critical that all students acquire computational thinking skills. Technology practice is most successful when embedded within authentic contexts, thus this paper presents a study that facilitated the learning of two concepts of computational thinking: sequencing and orientation within culturally embedded technology practice. The study’s vision is to assist mainstream Māori learners from low socio-economic backgrounds to develop an understanding of related concepts of computational thinking. The research design drew on Māori values and practice that situates learning within authentic Māori contexts. Kaupapa Māori pedagogies were used in our design-based intervention programme to achieve the research goal. The focus of the project was to improve digital technologies learning outcomes to ensure Māori tamariki (children) see themselves as comfortably situated in a digital world.

text: Computational thinking for young indigenous learners in New Zealand This article presents the findings from a study aimed to investigate how the computational thinking aspect of digital technologies can be embedded authentically into students’ technological practice. The project explored teaching and learning computational thinking in context and particularly focus on technological needs and practice for young Māori learners.
There is recognition internationally about the need for digital technologies within the curriculum. Computational thinking is a critical component of this and is defined as an approach to problem-solving, designing computer systems, and understanding related human behaviours, while drawing on fundamental ideas of computing. Therefore, it is critical that all students acquire computational thinking skills. Technology practice is most successful when embedded within authentic contexts, thus this paper presents a study that facilitated the learning of two concepts of computational thinking: sequencing and orientation within culturally embedded technology practice. The study’s vision is to assist mainstream Māori learners from low socio-economic backgrounds to develop an understanding of related concepts of computational thinking. The research design drew on Māori values and practice that situates learning within authentic Māori contexts. Kaupapa Māori pedagogies were used in our design-based intervention programme to achieve the research goal. The focus of the project was to improve digital technologies learning outcomes to ensure Māori tamariki (children) see themselves as comfortably situated in a digital world.

year: 2024