ABSTRACT
Whole-genome duplication (WGD) occurs in all kingdoms and impacts speciation, domestication, and cancer outcome. However, doubled DNA management can be challenging for nascent polyploids. The study of within-species polyploidy (autopolyploidy) permits focus on this DNA management aspect, decoupling it from the confounding effects of hybridization (in allopolyploid hybrids). How is autopolyploidy tolerated, and how do young polyploids stabilize? Here, we introduce a powerful model to address this: the genus Cochlearia, which has experienced many polyploidization events. We assess meiosis and other polyploid-relevant phenotypes, generate a chromosome-scale genome, and sequence 113 individuals from 33 ploidy-contrasting populations. We detect an obvious autopolyploidy-associated selection signal at kinetochore components and ion transporters. Modeling the selected alleles, we detail evidence of the kinetochore complex mediating adaptation to polyploidy. We compare candidates in independent autopolyploids across three genera separated by 40 million years, highlighting a common function at the process and gene levels, indicating evolutionary flexibility in response to polyploidy.
Subject(s)
Evolution, Molecular , Genome, Plant , Kinetochores , Polyploidy , Kinetochores/metabolism , Gene Duplication , Adaptation, Physiological/genetics , Meiosis/geneticsABSTRACT
In the fall of 2013, the authors received funding to help develop and implement an afterschool wellness program alongside Indigenous youth aged 6-10 years old in the North Central neighborhood of Regina, Saskatchewan, Canada. The Growing Young Movers (GYM) afterschool program was funded, in part, as a corrective response to a broader social trend in which Indigenous youth in this neighborhood reported declining health and wellness outcomes, as well as multiple other barriers to social inclusion. This article discusses the reflections of three senior high school Indigenous youth (16-18 years old) who participated in the afterschool program as peer-mentors over a 2-year period from 2015 to 2017. Our inquiry reveals how these youth viewed the program-and their role(s) within it-in far more complex, active, and even political terms, than the program's initial framing as a physical activity-based "intervention" had anticipated. Our analysis (re)positions youth according to their own personalized voice and narratives as: cultural leaders, knowledge holders, and as agents of change in their community.
ABSTRACT
STUDY DESIGN: Generic qualitative design. OBJECTIVES: To explore how Chinese adults living with spinal cord injury (SCI) viewed the prospect of inpatient peer support programs within a rehabilitation setting. SETTING: Hospital in China. METHODS: A purposive sample of adult inpatients with SCI (N = 6) currently undergoing rehabilitation was recruited. Each participant was interviewed twice. Twelve interview transcripts were analyzed using a thematic method. RESULTS: Five higher-order themes were developed. First, participants had unique backgrounds and personal lives before and after their SCI and reported frustrations about their lives resulting from their SCI. Second, participants reported varying degrees of satisfaction with their rehabilitation and identified the facilitators and barriers to their rehabilitation. Third, their perspectives on peer support were shaped by their rehabilitation goals. For example, participants who solely focused on the recovery of physical functioning noted that peers could help to supplement existing rehabilitation programming by guiding their rehabilitation exercises. Participants who concentrated on their future lives believed peers could teach them new skills to facilitate their integration in the community. However, some participants felt they could not trust peers' advice because peers are not healthcare providers. Fourth, peer support delivery options varied from online chat groups (i.e., WeChat), in-person conversations, and mentoring lectures. Finally, anticipated outcomes were related to obtaining practical and emotional support from peers, being motivated, and feeling understood. CONCLUSIONS: Participants harbored mixed views on potential use-value and necessity of hospital-based peer support programs, which could inform future utilization of SCI peer support within Chinese hospitals.
Subject(s)
Inpatients , Spinal Cord Injuries , Adult , China , Hospitals , Humans , Peer GroupABSTRACT
Adaptive gene flow is a consequential phenomenon across all kingdoms. Although recognition is increasing, there is no study showing that bidirectional gene flow mediates adaptation at loci that manage core processes. We previously discovered concerted molecular changes among interacting members of the meiotic machinery controlling crossover number upon adaptation to whole-genome duplication (WGD) in Arabidopsis arenosa. Here we conduct a population genomic study to test the hypothesis that adaptation to WGD has been mediated by adaptive gene flow between A. arenosa and A. lyrata. We find that A. lyrata underwent WGD more recently than A. arenosa, suggesting that pre-adapted alleles have rescued nascent A. lyrata, but we also detect gene flow in the opposite direction at functionally interacting loci under the most extreme levels of selection. These data indicate that bidirectional gene flow allowed for survival after WGD, and that the merger of these species is greater than the sum of their parts.
Subject(s)
Adaptation, Physiological/genetics , Arabidopsis/genetics , Gene Duplication , Genome, Plant , Genes, Plant , Meiosis/genetics , Ploidies , Polymorphism, Genetic , Species SpecificityABSTRACT
Ploidy-variable species allow direct inference of the effects of chromosome copy number on fundamental evolutionary processes. While an abundance of theoretical work suggests polyploidy should leave distinct population genomic signatures, empirical data remains sparse. We sequenced ~300 individuals from 39 populations of Arabidopsis arenosa, a naturally diploid-autotetraploid species. We find that the impacts of polyploidy on population genomic processes are subtle yet pervasive, such as reduced efficiency of purifying selection, differences in linked selection and rampant gene flow from diploids. Initial masking of deleterious mutations, faster rates of nucleotide substitution and interploidy introgression likely conspire to shape the evolutionary potential of polyploids.
Subject(s)
Arabidopsis/genetics , Gene Duplication , Gene Flow , Genome, Plant , Evolution, Molecular , MetagenomicsABSTRACT
The purpose of this study was to examine the role of a sport program in the lives of homeless men with severe mental illnesses and addictions. Interviews were conducted with eight men who attended a floor hockey program, and data examined using categorical-content narrative methodology. Five themes captured the role of the floor hockey program in the men's lives: (a) relationships with program leader, (b) therapy, (c) community, (d) action, and (e) achievement. These themes were interpreted using theories of masculinity (Connell, 1995; Gough, 2014). Relationships with the program leader and other men, and ways in which they were allowed to play with physicality, provided opportunities to accumulate masculine capital (i.e., ways in which competence in traditionally masculine behaviors provides masculine credit). Practically, the findings suggest that sport program delivery for men such as those in this study can be enhanced by providing opportunities for accruing masculine capital.
Subject(s)
Ill-Housed Persons/psychology , Masculinity , Men/psychology , Mentally Ill Persons/psychology , Psychiatric Rehabilitation/methods , Sports/psychology , Adult , Canada , Humans , Male , Middle Aged , Social Capital , Urban PopulationABSTRACT
Felsenstein's pruning algorithm allows one to calculate the probability of any particular data pattern arising on a phylogeny given a model of character evolution. Here we present a similar dynamic programming algorithm. Our algorithm treats the tree and model as known. The algorithm makes it feasible to calculate the probability that a randomly selected character will be a member of a particular class of character patterns. Specifically, we are interested in binning patterns by the number of parsimony steps and the set of states observed at the tips of the tree. This algorithm was developed to expand the range of data set sizes that can be used with Waddell et al.'s marginal testing approach for assessing the adequacy of a model. The algorithms introduced can also be used in likelihood calculations which correct for ascertainment biases. For example, Lewis introduced an Mkv model which corrects for the lack of constant sites. The probability of a constant pattern arising can be calculated using the algorithm that we present, or by enumerating all possible constant patterns and calculating the probability of each one. Because the number of constant data patterns is small, both methods are efficient. However, elaborations of the Mkv model (such as those in Nylander et al) require calculating the probability of parsimony-uninformative patterns arising. For large trees and characters with many possible character states, the number of possible parismony-uninformative patterns is immense. In these cases, the algorithms introduced here will be more efficient. The algorithm has been implemented in open source software written in C++.