Genomic differentiation with isolation by distance along a latitudinal gradient in the spotted-leg treefrog Polypedates megacephalus

The patterns of isolation by distance (IBD) entailing increased genetic differentiation among populations have aroused extensive concerns for evolutionary biologists. Although the IBD may act on spatial processes contributing to the genetic differentiation among populations in anuran species, the factors shaping the IBD of frogs among populations in natural systems are largely unknown. Here, we studied the genetic differentiation among six populations with 24 individuals of the spotted-leg treefrog along a latitudinal gradient (1860.31 km) based on 1020 single nucleotide polymorphisms from restriction site-associated DNA sequencing. The results showed that the genetic diversity differed significantly among populations and that the insular populations had higher genetic diversity than the mainland populations. Furthermore, we also found a significant genetic differentiation among populations (F_ST = 0.277) and no sign of inbreeding (F_UNI = −0.145). The IBD was detected for all populations, and a higher degree of the IBD was indicated when controlling for the effects of the isolation between Hainan and mainland populations caused by the Qiongzhou Strait. Our findings suggest that the form of the Qiongzhou Strait plays a key role in shaping the genetic diversity and population differentiation in treefrogs.     

不同生长阶段群体数量特征对产草量作用的分析

在相同的光，温，水，肥条件下，同时对营养生长期的高羊茅和生殖生长期的多年生黑麦草人工草地产草量和群体数量特征的定量关系进行研究。在营养生长期，参数的变异程度小于生殖生长期。营养生长期各因子对产草量直接作用的程度排序这：叶面积指数〉草丛高度〉分蘖密度，生殖生长期为；草丛高度〉叶面积指数〉分蘖密度。     

Across-breed validation study confirms and identifies new loci associated with sexual precocity in Brahman and Nellore cattle

The aim of this study was to identify candidate regions associated with sexual precocity in Bos indicus. Nellore and Brahman were set as validation and discovery populations, respectively. SNP selected in Brahman to validate in Nellore were from gene regions affecting reproductive traits (G1) and significant SNP (p ≤ 10^–3) from a meta-analysis (G2). In the validation population, early pregnancy (EP) and scrotal circumference (SC) were evaluated. To perform GWAS in validation population, we used regression and Bayes C. SNP with p ≤ 10^–3 in regression and Bayes factor ≥3 in Bayes C were deemed significant. Significant SNP (for EP or SC) or SNP in their ±250 Kb vicinity region, which were in at least one discovery set (G1 or G2), were considered validated. SNP identified in both G1 and G2 were considered candidate. For EP, 145 SNP were validated in G1 and 41 in G2, and for SC, these numbers were 14 and 2. For EP, 21 candidate SNP were detected (G1 and G2). For SC, no candidate SNP were identified. Validated SNP and their vicinity region were located close to quantitative trait loci or genes related to reproductive traits and were enriched in gene ontology terms related to reproductive success. These are therefore strong candidate regions for sexual precocity in Nellore and Brahman.     

中国河西走廊草地农业的基本格局和它的系统相悖─—草原退化的机理初探─—

河西走廊的草地资源位于西北荒漠的大背景中，由山地、荒漠和绿洲三个子系统构成，其中荒漠子系统居主导地位，具有先天的脆弱性。它们在人为干预下，在自然生态系统的农业化过程中，发生了山地一绿洲一荒漠组成的耦合农业系统。由于耦合不够完善，它所固有的相悖因素未能有效控制，形成涵有系列相悖因子群的系统相悖。主要表现为时间相悖，空间相悖和种间相悖。三者互相影响，但时间相悖起主导作用，使系统的生态危机加剧。它通常表现为草原退化。对草地农业生态系统的自由能的调控，保持自由能的积累和输出基本相当，是防止草原退化的根本出路。草原退化是草地对于草食动物压迫的对策系统和动物对于草地负荷行为的对策系统的综合反映。放牧程度可以作为草原退化过程的向量系统，但不是草原退化的本质。     

鸡丘脑背外侧核纤维联系——HRP法研究

鸡丘脑背外侧核前部与上纹状体、新纹状体、外纹状体及圆核和视顶盖有纤维交互投射;丘脑背外侧核后部与上纹状体、新纹状体及圆核和视顶盖有纤维交互投射,且与丘脑其他核团有较多的联系。     

新疆塔里木盆地两河流域野生麻资源调查

麻具有药用、轻纺、保健、造纸、制作药烟、蜜源等多种经济价值.新疆塔里木盆地两河(叶尔羌河、塔里木河)流域是野生麻(大叶白麻Poacynum hendersonii、白麻P.pictum、罗布麻Apocynum venetum)的主要产区,其中大叶白麻分布广,面积大,储量多.按有关分类方法,将野生麻资源划分为6个群系12个群丛.野生麻分布面积23.56万hm2,有麻面积18.12万hm2,其中大叶白麻占99.51%;白麻占0.49%.鲜麻总产量59.35万t,折合干麻总产量24.41万t.为更好的利用野生麻资源,在对其种类、分布、面积、生物量调查的基础上,对麻的开发前景、野生麻田的保护管理及改良培育、人工麻田的建立、科技攻关5个方面提出了建议.     

2种方法在荒漠草原植物种群分布格局中的适用性比较

研究首次比较了2种方法在测定荒漠草原6种植物种群分布格局中的适用性.结果表明,方差均值比率法及聚集强度指数法中的多个指数都适合于这6种植物分布格局的计算.但其中的聚块性指数法的运算难度较大,宜慎用.比较结果这6种植物种群皆为聚集分布,但聚集程度有所差别.     

贺兰山野生有蹄类动物的经济价值及种群动态变化

记述了贺兰山的4种野生有蹄类动物——马麝、马鹿、岩羊、鹅喉羚的经济价值及目前的种群动态变化,对贺兰山野生有蹄类动物的种群致危原因进行了分析,并据此提出了相应的保护管理建议。     

电刺激疑核对TNBS诱导的IBD大鼠TGF－β表达的影响

为探讨疑核对炎症性肠病（inflammatory bowel disease,IBD）相关细胞因子TGF-β的调控作用以及在IBD的发生发展过程中发挥的作用,以三硝基苯磺酸（TNBS）诱导IBD大鼠动物模型通过Real-Time PCR和ELISA方法,利用疑核定位技术,检测急性电刺激疑核前后,细胞因子TGF-β在TNBS诱导的IBD大鼠结肠、胸腺、脾脏、外周血淋巴细胞中mRNA水平的变化和血清中蛋白浓度的变化。结果表明,急性电刺激IBD大鼠疑核后TGF-βmRNA表达水平在结肠、脾脏和外周血淋巴细胞中均显著高于对照组和假刺激组;而在胸腺中TGF-βmRNA表达降低。急性电刺激IBD大鼠疑核后血清中TGF一8蛋白浓度显著高于对照组和假刺激组。由此认为,疑核可能通过对IBD相关细胞因子TGF一8的调控,介导IBD的发生、发展过程,从而对IBD的发生、发展发挥调节作用。     

Including an additional systematic environmental effect within a generation in an evaluation model improves accuracy of prediction of breeding values in a closed herd of pigs

The present study evaluated the advantage of mixed‐model techniques over a selection index under different magnitudes of an additional systematic environmental effect (ASEE) in terms of accuracy of prediction and expected genetic gain. The data attempted to simulate a closed herd in a pig breeding program. The base population (G₀) consisted of 10 males and 50 females. Six generations (G₀ to G₅) were selected by using a selection index of three traits without overlapping. Additional systematic environmental constants with four levels in a generation were assigned from a uniform distribution at different ranges. Breeding values of animals in the last generation (G₅) were estimated on the basis of an index of individual phenotype (SI‐U), SI‐U adjusted for ASEE using a least‐squares mean (SI‐A), best linear unbiased prediction using an animal model excluding ASEE (AM‐E), and an animal model including ASEE (AM‐I). Accuracy of prediction and expected genetic gain were larger by the animal model than by the selection index, even if heritability of the traits selected was high and ASEE was set to zero. When ASEE was zero, the accuracy of prediction and expected genetic gain given by SI‐U and AM‐I were similar to those given by SI‐A and AM‐E, respectively. However, the differences in accuracy and expected gain between SI‐U and AI‐A and between AM‐I and AM‐E increased as the range of ASEE increased. It was concluded that selection based on an animal model was more effective than index selection, even if the herd environment was uniform and traits with high heritability were selected, and that it should be always included in an evaluation model, however slight any systematic environmental effect may be in a closed herd.