分类： 生物学 >> 遗传学 提交时间： 2022-12-22
摘要： The Green Sea Turtle (Chelonia mydas) is an umbrella species in the South China Sea, a Chinese national first-level protected wild animal, and the only sea turtle that nests in Chinese waters.The largest C. mydasnesting ground is distributed in the Xisha(Paracel) Islands, which plays a vital role in the survival of sea turtle populations in China. This study reveals the genetic diversityand population structure of the breeding population of C. mydason the Xisha Islandsusing three mitochondrial markers.A total of 15D-loop, 5 Cytochrome b (Cytb), and 7 Cytochrome C Oxidase subunit I (COI)haplotypes were identified in the breeding population of C. mydason theXisha Islands.D-loop haplotypes are distributed in clades III,IV,and VIIIof theC. mydasmitochondrialcontrol region.Clade IV is first clade to bediscoveredin this C. mydaspopulation, and five D-loop haplotypes were alsonewly identified. The haplotype and nucleotide diversity were calculated for each marker: D-loop (0.415 haplotype diversity, 0.00204 nucleotide diversity), Cyt b(0.140, 0.00038) and COI (0.308, 0.00083). The average genetic distance (p) of each molecular markerwas less than0.01. Neutral detection and nucleotide mismatch analysis suggested that the breeding population of C. mydasin the Xisha Islandsdid not experience a population expansion event in recent history.It is recommended that a sea turtle protection area be established in the Xisha Islandsarea to strengthen protection and effectively protect the uniqueness and sustainability of the breeding population of C. mydasin the South China Sea.绿海龟是中国南海的伞护种，国家一级保护野生动物，也是唯一在我国海域筑巢的海龟。西沙群岛分布有中国最大的绿海龟产卵场，对我国海龟种群的生存起着至关重要的作用。本研究利用3个线粒体基因标记揭示了西沙群岛绿海龟繁殖种群的遗传多样性和种群结构。在西沙群岛绿海龟繁殖种群共鉴定出15个D-loop单倍型、5个Cytb单倍型和7个COI单倍型；D-loop单倍型分布在进化支Ⅲ、Ⅳ和Ⅷ，其中进化支Ⅳ首次在西沙群岛绿海龟繁殖种群中发现，且最新发现了5个D-loop单倍型。计算每个标记的单倍型和核苷酸多样性: D-loop（单倍型多样性为0.415，核苷酸多样性为0.00204）、Cyt b（0.140, 0.00038）和COI（0.308, 0.00083）。各分子标记的平均遗传距离（p）均≦0.01。中性检测和核苷酸错配分析显示，西沙群岛绿海龟繁殖种群在近期历史上未经历种群扩张事件。建议在西沙群岛地区建立海龟保护区加强保护，以有效保护中国南海地区绿海龟繁殖种群的特殊性和可持续性。
分类： 计算机科学 >> 计算机科学的集成理论 提交时间： 2018-04-19 合作期刊: 《计算机应用研究》
摘要： 几何约束求解是CAD建模中的关键技术。针对求解质量不高和求解速度慢的问题，进行了研究。提出了一种鱼群算法和混沌算法相结合的几何约束求解方法。首先，将CAD模型中的几何约束关系表示为一组代数方程组；然后，利用代数方程组来构造目标函数。将几何约束求解问题转换为目标函数的优化问题。最后，使用混沌算法来改进鱼群算法以寻找目标函数的最优解。实验结果表明：该方法可以有效地解决几何约束问题。
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