title: Enzyme evolution: innovation is easy, optimization is complicated

authors: Newton, Matilda S.

abstract: Enzymes have been evolving to catalyze new chemical reactions for billions of years, and will continue to do so for billions more. Here, we review examples in which evolutionary biochemists have used big data and high-throughput experimental tools to shed new light on the enormous functional diversity of extant enzymes, and the evolutionary processes that gave rise to it. We discuss the role that gene loss has played in enzyme evolution, as well as the more familiar processes of gene duplication and divergence. We also review insightful studies that relate not only catalytic activity, but also a host of other biophysical and cellular parameters, to organismal fitness. Finally, we provide an updated perspective on protein engineering, based on our new-found appreciation that most enzymes are sloppy and mediocre.

text: Enzyme evolution: innovation is easy, optimization is complicated Enzymes have been evolving to catalyze new chemical reactions for billions of years, and will continue to do so for billions more. Here, we review examples in which evolutionary biochemists have used big data and high-throughput experimental tools to shed new light on the enormous functional diversity of extant enzymes, and the evolutionary processes that gave rise to it. We discuss the role that gene loss has played in enzyme evolution, as well as the more familiar processes of gene duplication and divergence. We also review insightful studies that relate not only catalytic activity, but also a host of other biophysical and cellular parameters, to organismal fitness. Finally, we provide an updated perspective on protein engineering, based on our new-found appreciation that most enzymes are sloppy and mediocre.

year: 2018

title: Contrasting phylogeographical patterns for springtails reflect different evolutionary histories between the Antarctic Peninsula and continental Antarctica

authors: McGaughran, Angela

subjects: Antarctica

abstract: Aim: We examined the genetic structure among populations and regions for the springtails Cryptopygus antarcticus antarcticus and Gomphiocephalus hodgsoni (Collembola) to identify potential historical refugia and subsequent colonization routes, and to examine population growth/expansion and relative ages of population divergence.
Location Antarctic Peninsula for C. a. antarcticus; Antarctic continent (southern Victoria Land) for G. hodgsoni.
Methods: Samples were collected from 24 and 28 locations across the Antarctic Peninsula and southern Victoria Land regions for C. a. antarcticus and G. hodgsoni, respectively. We used population genetic, demographic and nested clade analyses based on mitochondrial DNA (cytochrome c oxidase subunit I and subunit II).
Results: Both species were found to have population structures compatible with the presence of historical glacial refugia on Pleistocene (2 Ma–present) time-scales, followed by post-glacial expansion generating contemporary geographically isolated populations. However, G. hodgsoni populations were characterized by a fragmented pattern with several 'phylogroups' (likely ancestral haplotypes present in high frequency) retaining strong ancestral linkages among present-day populations. Conversely, C. a. antarcticus had an excess of rare haplotypes with a much reduced volume of ancestral lineages, possibly indicating historical founder/bottleneck events and widespread expansion.
Main conclusions: We infer that these differences reflect distinct evolutionary histories in each locality despite the resident species having similar life-history characteristics. We suggest that this has predominantly been influenced by variation in the success of colonization events as a result of intrinsic historical glaciological differences between the Antarctic Peninsula and continental Antarctic environments.

text: Contrasting phylogeographical patterns for springtails reflect different evolutionary histories between the Antarctic Peninsula and continental Antarctica Aim: We examined the genetic structure among populations and regions for the springtails Cryptopygus antarcticus antarcticus and Gomphiocephalus hodgsoni (Collembola) to identify potential historical refugia and subsequent colonization routes, and to examine population growth/expansion and relative ages of population divergence.
Location Antarctic Peninsula for C. a. antarcticus; Antarctic continent (southern Victoria Land) for G. hodgsoni.
Methods: Samples were collected from 24 and 28 locations across the Antarctic Peninsula and southern Victoria Land regions for C. a. antarcticus and G. hodgsoni, respectively. We used population genetic, demographic and nested clade analyses based on mitochondrial DNA (cytochrome c oxidase subunit I and subunit II).
Results: Both species were found to have population structures compatible with the presence of historical glacial refugia on Pleistocene (2 Ma–present) time-scales, followed by post-glacial expansion generating contemporary geographically isolated populations. However, G. hodgsoni populations were characterized by a fragmented pattern with several 'phylogroups' (likely ancestral haplotypes present in high frequency) retaining strong ancestral linkages among present-day populations. Conversely, C. a. antarcticus had an excess of rare haplotypes with a much reduced volume of ancestral lineages, possibly indicating historical founder/bottleneck events and widespread expansion.
Main conclusions: We infer that these differences reflect distinct evolutionary histories in each locality despite the resident species having similar life-history characteristics. We suggest that this has predominantly been influenced by variation in the success of colonization events as a result of intrinsic historical glaciological differences between the Antarctic Peninsula and continental Antarctic environments.

year: 2009

title: Claiming collective space: Kaupapa Maori in psychology

authors: Levy, Michelle Patricia

subjects: Maori

abstract: From its inception, the Psychology Department at the University of Waikato has had a focus on issues of culture, particularly those of relevance for Maori, with these early foundations laid by Emeritus Professor James Ritchie, who in 1965 took up the founding chair of the Department. These foundations have continued to be built on, utilising a variety of different strategies. Drawing on a research base which has emerged primarily from within the Maori and Psychology Research Unit at Waikato University, this paper explores strategies which have served to carve out and claim space for Maori, both within the department, and within the wider discipline of psychology.

text: Claiming collective space: Kaupapa Maori in psychology From its inception, the Psychology Department at the University of Waikato has had a focus on issues of culture, particularly those of relevance for Maori, with these early foundations laid by Emeritus Professor James Ritchie, who in 1965 took up the founding chair of the Department. These foundations have continued to be built on, utilising a variety of different strategies. Drawing on a research base which has emerged primarily from within the Maori and Psychology Research Unit at Waikato University, this paper explores strategies which have served to carve out and claim space for Maori, both within the department, and within the wider discipline of psychology.

year: 2008