The type I antifreeze protein gene family in Pleuronectidae

Antifreeze proteins (AFPs) protect marine teleosts from freezing in icy seawater by binding to nascent ice crystals and preventing their growth. It has been suggested that the gene dosage for AFPs in fish reflects the degree of exposure to harsh winter climates. The starry flounder, _Platichthys stellatus_, has been chosen to examine this relationship because it inhabits a range of the Pacific coast from California to the Arctic. This flatfish is presumed to produce type I AFP, which is an alanine-rich, amphipathic alpha-helix. Genomic DNA from four starry flounder was Southern blotted and probed with a cDNA of a winter flounder liver AFP. The hybridization signal was consistent with a gene family of approximately 40 copies. Blots of DNA from other starry flounder indicate that California fish have far fewer gene copies whereas Alaska fish have far more. This analysis is complicated by the fact that there are three different type I AFP isoforms. The first is expressed in the liver and secreted into circulation, the second is a larger hyperactive dimer also thought to be expressed in the liver, and the third is expressed in peripheral tissues. To evaluate the contribution of these latter two isoforms to the overall gene signal on Southern blots, hybridization probes for the three isoforms were isolated from starry flounder DNA by genomic cloning. Two clones revealed linkage of genes for different isoforms, and this was confirmed by genomic Southern blotting, where hybridization patterns indicated that the majority of genes were present in tandem repeats. The sequence and diversity of all three isoforms was sampled in the starry flounder genome by PCR. All coding sequences derived for the skin and liver isoforms were consistent with the proposed structure-function relationships for this AFP, where the flat hydrophobic side of the helix is conserved for ice binding. There was greater sequence diversity in the skin and hyperactive isoforms than in the liver isoform, suggesting that the latter evolved recently from one of the other two. The genomic PCR primers are currently being used to sample isoform diversity in related right-eyed flounders to test this hypothesis.

Operational Stress Injuries: Impact on Family Mental Health and Well-being

This study was part of a larger scoping review and environmental scan conducted for Veterans Affairs Canada on the effects of operational stress injuries (OSIs) on the mental health and wellbeing of Veterans’ families. This paper focuses broadly on the relationships between combat (and/or deployment more generally), OSIs (primarily post-traumatic stress disorder (PTSD)), and the family. Based on the scoping review, the paper finds that existing research investigates the impacts of a Veteran’s OSI on the family, but also how various aspects of the family (such as family functioning, family support, etc.) can impact a Veteran living with an OSI.

Family Background and Access to Post-Secondary Education: What Happened in the 1990's (Woking Paper 34)

This paper presents new evidence on the relationships between access to post-secondary education and family background. More specifically, we use the School Leavers Survey (SLS) and the Youth in Transition Survey (YITS)to analyze participation rates first in 1991, and then almost a decade later in 2000. Overall, post-secondary education participation rates rose over this period. However, participation is strongly related to parent’s education, and whereas participation increased for individuals with more highly educated parents (especially those who went to university), they increased rather less, or in some cases (especially for males) declined for those from lower parental education families. The already strong “effect” of parents’ education on post-secondary access became even greater in the 1990’s. Participation rates are also strongly related to family type, but whereas those from two parent families continue to have an advantage over single mother families, the gap generally shrunk in the 1990’s, especially where the mother had university level schooling. We also find a number of interesting trends by province.

A Recursive Income Model for Canadians : The Direct and Indirect Effects of Family Background (Working Paper 28)

This paper presents the results of a multi-equation income model which has been estimated for Canadian men and women which incorporates the effects of a number of important family background variables, including mother’s and father’s education, parents’ immigration status, their age at immigration, place of birth, language development, and learning background. Not only education, but also the individual’s tested literacy and numeracy levels are treated as intermediate outcomes which are affected by background and which, in turn, affect income. Many of the background variables are found to have important indirect effects on income which would be missed by more conventional approaches. We also find some interesting gender aspects with respect to the influences of parents’ educations on their children’s outcomes. Various policy implications of the findings are discussed.