Browsing by Author "Han Y"

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    Genomic signatures of cooperation and conflict in the social amoeba
    (1/01/2015) Ostrowski EA; Shen Y; Tian X; Sucgang R; Jiang H; Qu J; Katoh-Kurasawa M; Brock DA; Dinh C; Lara-Garduno F; Lee SL; Kovar CL; Dinh HH; Korchina V; Jackson LR; Patil S; Han Y; Chaboub L; Shaulsky G; Muzny DM; Worley KC; Gibbs RA; Richards S; Kuspa A; Strassmann JE; Queller DC
    © 2015 Elsevier Ltd. Summary Cooperative systems are susceptible to invasion by selfish individuals that profit from receiving the social benefits but fail to contribute. These so-called "cheaters" can have a fitness advantage in the laboratory, but it is unclear whether cheating provides an important selective advantage in nature. We used a population genomic approach to examine the history of genes involved in cheating behaviors in the social amoeba Dictyostelium discoideum, testing whether these genes experience rapid evolutionary change as a result of conflict over spore-stalk fate. Candidate genes and surrounding regions showed elevated polymorphism, unusual patterns of linkage disequilibrium, and lower levels of population differentiation, but they did not show greater between-species divergence. The signatures were most consistent with frequency-dependent selection acting to maintain multiple alleles, suggesting that conflict may lead to stalemate rather than an escalating arms race. Our results reveal the evolutionary dynamics of cooperation and cheating and underscore how sequence-based approaches can be used to elucidate the history of conflicts that are difficult to observe directly.
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    The responses of ‘Hayward’ kiwifruit to ethylene during regular and controlled atmosphere storage
    (Taylor and Francis Groupon behalf of the Royal Society of New Zealand, 2024-05-08) Han Y; Heyes J; Glowacz M; Nicholson S; Jeffery P; East A; Li M
    Maintaining kiwifruit firmness is key to global supply chain. Controlled atmosphere (CA) technology can maintain kiwifruit quality. However, there is a risk of ethylene (C2H4) accumulation in CA that may accelerate kiwifruit softening. The objectives of this study were to determine the impact of ethylene on kiwifruit quality in CA. ‘Hayward’ kiwifruit were stored in air and CA (5% CO2 + 2% O2) at 0°C, 95% RH for 13 weeks. Ethylene at concentrations of 10, 100, 1000 nL·L−1 was added after 3 weeks of storage. The responses of kiwifruit to ethylene were dose-dependent in both air and CA storage. Ethylene-induced kiwifruit softening was delayed and slowed by CA. However, white-core inclusions (WCI) disorder was observed after 8 weeks of exposure to 100 and 1000 nL·L−1 ethylene in CA. The lowest concentrations of ethylene (≤ 10 nL·L−1) in CA did not influence kiwifruit quality. This work demonstrates that kiwifruit sensitivity to ethylene is lower in CA than that in air, but excessive softening and WCI may negatively impact kiwifruit quality when exposed to a high ethylene concentration in CA for extended periods. Hence, ethylene monitoring and management may be less critical in kiwifruit stored in CA but are required.