人类胎儿的性别选择属自然选择

现代人类的祖先在数百万年的演化史中，不断为适应自然，逐渐地向现代人进化。     

建立以TK基因为标记将外源基因导入臭曲霉（Asper—gillus...

A new system for selection of transformed Aspergillus foetidus was reported. In this system, TK- A. foetidus which were constructed by homologous recombination of mutated TK gene of vaccinia virus with TK gene of A. foetidus were screened by adding BUdR in agar plates. Conditions for screen of TK+ A. foetidus strain, transformation of A. foetidus and selection of transformed TK- A. foetidus have been studied. By using this system, several transformed A. foetidus which contained HBsAg gene derived bf a promoter H8 cloned from genomic DNA of A. foetidus were isolated. It was demonstrated that HBsAg gene was integrated into the chromosome DNA of A. foetidus by Southern blot after many passages of spores. ELISA showed that HBsAg was positive in the growth medium (p/n = 20). The 22 nm particles which were very similar to the HBsAg particles in human serum were found in the growth medium by immunoelectromicroscope. Western blot also gave the specific bands. All these data showed that HBsAg gene was expressed in A. foetidus and the products were secreted into the growth medium. The selection system using TK gene as marker could generally be used to study the expression of foreign gene in A. foetidus.     

追溯山茱萸科植物的性状进化和生物地理学历史——方法选择的影响?

This study compares results on reconstructing the ancestral state of characters and ancestral areas of distribution in Cornaceae to gain insights into the impact of using different analytical methods. Ancestral character state reconstructions were compared among three methods (parsimony, maximum likelihood, and stochastic character mapping) using MESQUITE and a full Bayesian method in BAYESTRAITS and inferences of ancestral area distribution were compared between the parsimony-based dispersal-vicariance analysis (DIVA) and a newly developed maximum likelihood (ML) method. Results indicated that among the six inflorescence and fruit characters examined, "perfect" binary characters (no homoplasy, no polymorphism within terminals, and no missing data) are little affected by choice of method, while homoplasious characters and missing data are sensitive to methods used. Ancestral areas at deep nodes of the phylogeny are substantially different between DIVA and ML and strikingly different between analyses including and excluding fossils at three deepest nodes. These results, while raising caution in making conclusions on trait evolution and historical biogeography using conventional methods, demonstrate a limitation in our current understanding of character evolution and biogeography. The biogeographic history favored by the ML analyses including fossils suggested the origin and early radiation of Cornus likely occurred in the late Cretaceous and earliest Tertiary in Europe and intercontinental disjunctions in three lineages involved movements across the North Atlantic Land Bridge (BLB) in the early and mid Tertiary. This result is congruent with the role of NALB for post-Eocene migration and in connecting tropical floras in North America and Africa, and in eastern Asia and South America. However, alternative hypotheses with an origin in eastern Asia and early Trans-Beringia migrations of the genus cannot be ruled out.     

燕麦分子育种研究进展

燕麦是一种主要生长在温带冷凉地区的粮饲兼用作物,近年来燕麦的营养价值和降低胆固醇特性的发现使人们认识到燕麦及其制品是一种健康食品,促进了燕麦产业发展,对燕麦品种培育提出了更高要求。在此背景下,现代生物技术与常规育种技术结合是满足这一需求的重要途经。本文综述了国内外燕麦分子育种方面的研究进展:(1)我国燕麦种质资源的收集与遗传多样性研究。我国的燕麦种质资源收集工作起始于20世纪50年代,迄今收集并保存了5282份燕麦种质资源。对这些资源的遗传多样性分析研究表明,国内的燕麦种质资源中内蒙古和山西的资源多样性最高;(2)利用各种分子标记构建燕麦遗传连锁图谱研究;(3)一些重要农艺性状的QTL定位研究以及全基因组关联分析研究。包括产量、含油量、β-葡聚糖含量、蛋白质含量、抽穗期、抗病基因、抗冻性等重要农艺性状;(4)标记辅助基因组选择技术在燕麦中的应用;(5)燕麦遗传工程育种研究进展。同时,本文将国内的主要研究进展与国外相关的最新研究成果进行了比较,并对当前分子育种中存在的问题及今后的研究方向进行了探讨,希望能为今后通过生物技术手段培育燕麦新品种提供一定的参考。     

脊椎动物FoxO基因亚族的进化

本研究以脊椎动物FoxO作为研究对象,选取NCBI上公布的多个FoxO基因编码蛋白的核苷酸序列,重点分析Fox O蛋白质结构和功能的相似性与差异性,重建FoxO基因的系统发育树并进行选择压力分析,对FoxO基因亚族的起源和进化进行研究分析。结果显示:脊椎动物FoxO蛋白间Forhead结构域十分保守但核定位信号区结构差异较明显,尤其是FoxO6蛋白,并且多个磷酸化位点在哺乳动物FoxO6中缺失,削弱核输出信号,但在斑马鱼和原鸡的FoxO6中未缺失这些位点,推测其胞质定位调控作用仍十分重要。FoxO3中多个磷酸化位点可能与寿命延长作用相关。系统发育树表明FoxO1是FoxO基因的祖先基因,不同FoxO基因进化速率不同。选择压力分析结果显示FoxO基因过程每个位点经历不同的选择压,并且获得25个正选择位点,这些正选择位点可能对FoxO不同基因的形成和新功能的产生中具有十分重要的作用。     

2型糖尿病小鼠模型构建的研究进展

2型糖尿病(type 2 diabetes mellitus, T2DM)的病因主要在于细胞控制动态平衡能力的缺失,以及这些细胞所构成的组织或器官功能的失调。为了更好地研究和治疗2型糖尿病,人们借助不同动物模型去了解不同细胞、组织和器官的功能。在动物模型的选择上,小鼠因为其基因和表型能很好地模拟2型糖尿病而被广泛使用。2型糖尿病小鼠模型种类繁多,包括:自发突变性模型、热量过量性模型、外科和化学诱导性模型、常用转基因小鼠模型、专门用于研究环境对基因影响性的模型、CRISPR-Cas9构建模型以及特定的糖尿病肾病模型。本文就2型糖尿病现有的小鼠动物模型及其构建的方式给予简要综述,以期帮助广大科研工作者了解并更好地选择2型糖尿病小鼠实验模型。     

Evolutionary history and climate conditions constrain the flower colours of woody plants in China

进化历史和气候条件共同影响中国木本植物花色的分布 本研究以中国木本植物为研究对象,主要探讨两个问题：(1)不同生活型物种花色组成的差异;(2)生物地理区、进化年龄和气候条件对不同花色地理分布格局的影响。研究使用7673种木本植物的物种分布数据和花色信息(分为白色、红色、黄色、黄绿色、绿色和蓝紫色),并结合属级系统进化树来比较不同生活型(包括灌木、乔木和藤本)物种花色组成的差异,分析不同生物地理区、进化年龄和现代气候对花色地理格局的影响。研究结果表明,与乔木和藤本植物相比,灌木具有更高比例 的由花青素着色的红色花和蓝紫色花物种。中国木本植物的花色地理格局受到区域效应和现代气候(尤其是降水和UVB辐射)的共同影响。倾向于蜂媒传粉的黄色花和蓝紫色花物种和由花青素着色、耐环境胁迫的红色花和蓝紫色花物种比例在中国西北部地区更高。绿色花物种的进化起源更早,但进化时间对花色地理格局的解释力很弱。这些结果说明中国木本植物花色的地理格局受到进化历史和现代环境的共同影响。     

基于Hyperion的锡林郭勒草原光合植被、非光合植被覆盖度估算

掌握草原生态系统光合植被覆盖度(fPV)与非光合植被覆盖度(fNPV)时空动态对了解干旱半干旱草原生态系统特征(覆盖状况、火灾负载、载畜量、干扰及恢复等)及进行科学、有效地草地资源管理具有重要的意义。选取锡林郭勒典型草原为试验区,以Hypeiron高光谱数据为数据源,利用NDVI-CAI三元线性混合模型对试验区fPV和fNPV的时空动态分布进行了估算,并对不同端元选择方法(最小包含端元特征法、纯净象元指数法和实测法)对估算结果的影响进行了比较分析。研究结果表明,NDVI-CAI三元线性混合模型是同时估测锡林郭勒草原fPV和fNPV的有效方法,且估算的fPV和fNPV的季节变化与牧草的物候发育特征相吻合。不同端元选择方法对估算精度具有一定的影响,其中基于最小包含端元特征法提取端元进行估算的精度最高,fPV估算的均方根误差RMSE=4.57,估算精度EA=91.2%;fNPV估算的RMSE=5.90,EA=67.91%(样本数N=52)。