First chromosome scale genomes of ithomiine butterflies (Nymphalidae: Ithomiini): Comparative models for mimicry genetic studies

The ithomiine butterflies (Nymphalidae: Danainae) represent the largest known radiation of Müllerian mimetic butterflies. They dominate by number the mimetic butterfly communities, which include species such as the iconic neotropical Heliconius genus. Recent studies on the ecology and genetics of speciation in Ithomiini have suggested that sexual pheromones, colour pattern and perhaps hostplant could drive reproductive isolation. However, no reference genome was available for Ithomiini, which has hindered further exploration on the genetic architecture of these candidate traits, and more generally on the genomic patterns of divergence. Here, we generated high-quality, chromosome-scale genome assemblies for two Melinaea species, M. marsaeus and M. menophilus, and a draft genome of the species Ithomia salapia. We obtained genomes with a size ranging from 396 to 503 Mb across the three species and scaffold N50 of 40.5 and 23.2 Mb for the two chromosome-scale assemblies. Using collinearity analyses we identified massive rearrangements between the two closely related Melinaea species. An annotation of transposable elements and gene content was performed, as well as a specialist annotation to target chemosensory genes, which is crucial for host plant detection and mate recognition in mimetic species. A comparative genomic approach revealed independent gene expansions in ithomiines and particularly in gustatory receptor genes. These first three genomes of ithomiine mimetic butterflies constitute a valuable addition and a welcome comparison to existing biological models such as Heliconius, and will enable further understanding of the mechanisms of adaptation in butterflies.     

小麦Kr基因在小麦与玉米或鸭茅状摩擦禾杂交中的失活

用３７个小麦（Ｔｒｉｔｉｃｕｍａｅｓｔｉｖｕｍ）品种（系）为母本,分别与黑麦（Ｓｅｃａｌｅｃｅｒｅａｌｅ）、球茎大麦（Ｈｏｒｄｅｕｍｂｕｌｂｏｓｕｍ）、玉米（Ｚｅａｍａｙｓ）和鸭茅状摩擦禾（Ｔｒｉｐｓａｃｕｍｄａｃｔｙｌｏｉｄｅｓ）杂交,比较其亲和性,小麦和玉米或鸭茅状摩擦禾杂交比小麦与黑麦或球茎大麦杂交的亲和性显著提高。携带着显性Ｋｒ１和Ｋｒ２基因的小麦品种Ｈｏｐｅ与黑麦杂交,不能形成胚,而与玉米及鸭茅状摩擦禾杂交时,成胚率分别达１６．００％和３２．５０％。表明控制小麦与黑麦及球茎大麦杂交亲和性的Ｋｒ基因系统在小麦与玉米及小麦与鸭茅状摩擦禾属间杂交中失活。讨论了还存在有其它控制小麦属间杂交亲和性的遗传调控系统的可能性。     

An efficient synthesis of methyl tetra-o-hexyl gentiooctaoside, an octaosyl analogue of ANP receptor antagonist HS-142-1

Methyl

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, a 3-O hexyl analogue of the octaosyl component of fungal lipooligosaccharide HS-142-1, was stereo- and regioselectively synthesized as a potent antagonist for the tetrameric atrial natriuretic peptide (ANP) receptors.     

动态神经网络中的同步振荡

目前有一种假设认为同一视觉对象是由一群神经元的同步振荡活动来表征的。这一神经元发放活动的时间特性,是解决视觉信息处理中“结合问题（Ｂｉｎｄｉｎｇｐｒｏｂｌｅｍ）”的可能机制。本文用我们所提出的一种简化现实性神经网络模型［１］所构造的时滞非线性振子网络［２］,模拟生物神经网络的同步振荡活动。并考虑了振子各参数的设置与振荡活动的关系,以及网络振子间耦联对同步活动的影响．     

华南植物区系的评论（三） Ⅳ．旋花科一些种类的修订

作者编写《广东植物志》旋花科时,对据本科的花粉形态特征划分族和属的意义予肯定并采用之;现将其中４个属、６个分类单位的分类或其分布等予于报道．对华南和北越的心萼薯属植物作修订;论证本地区不产ＡｎｉｓｅｉａＣｈｏｉｓｙ．被认为该属的狭花心萼薯Ａ．ｓｔｅｎａｎｔｈｏ和大花心萼薯Ａ．ｓｔｅｎａｎｔｈａｖａｒ．ｍａｃｒｏｓｒｅｐｈａｎａ均是龙骨萼牵牛Ｉｐｏｍｏｅａａｔｅｎａｎｔｈａ;心萼薯Ａｎｉｓｅｉａｂｉｆｌｏｒａ是毛牵牛Ａｎｉｓｅｉａｓｉｎｅｎｓｉｓ;云南土丁桂Ｅｖｏｌｖｕｌｕｓｙｕｎｎａｎｅｎｓｉｓ作新异名处理．应为我国新纪录的归化种（美洲土丁桂Ｅ．ｎｕｍｍｕｌａｒｉｕｓ）;裂叶鳞蕊藤Ｌｅｐｉｓｔｅｍｏｎｌｏｂａｔｕｍ为越南新纪录．也分布于我国江西、海南;海滩牵牛Ｉｐｏｍｏｅｏｓｔｏｌｏｎｉｆｅｒａ这个开白花的海滩植物是一种中草药;虎脚牵牛Ｉｐｏｍｏｅａｐｅｓ－ｔｉｇｒｉｄｉｓ是亚洲和非洲东部热带的广布种,广东大陆西部也有;它是ＩｐｏｍｏｅａＬｉｎｎ．选模式种;这属的中名,本文恢复《广州植物志》（１９５６）等采用的牵牛属,会比较确切用“番薯属”为这个属的中名。     

陕西乾县的旧石器

石制品八件,发现于陕西乾县大北沟黄土之下砂砾粘土层中,和更新世晚期的哺乳类化石伴存。另外由大北沟附近地表拾到一件手斧,和蓝田平梁的大尖状器相似,推测为旧石器时代的文化遗物。