African DNA lineages in mitochondrial gene pool of Europeans

Mitochondrial DNA (mtDNA) nucleotide sequences of African origin have been found at low frequency (1%, in average) in different European populations. In the present study, data on mtDNA variability in populations of Eurasia and Africa are analyzed and search of African-specific lineages present in Europeans is conducted. The results of analysis indicate that, despite a high diversity of African mtDNA haplotypes found in Europeans, monophyletic clusters of African mtDNA lineages, arisen in Europe and characterized by long-term diversity, are nearly absent in Europe. Only two respective clusters (belonging to haplogroups L1b and L3b), which evolutionary age does not exceed 6.5 thousands years, were revealed. Comparative analysis of distribution of frequencies of autosomal microsatellite alleles found in Russian individuals, carrying the African-specific mitochondrial haplotypes, in populations of Europe and Africa has indicated that autosomal genotypes of those Russian individuals are characterized by the presence of alleles characteristic mostly for Europeans.     

Differentiation of mitochondrial DNA and Y chromosomes in Russian populations

The genetic composition of the Russian population was investigated by analyzing both mitochondrial DNA (mtDNA) and Y-chromosome loci polymorphisms that allow for the different components of a population gene pool to be studied, depending on the mode of DNA marker inheritance. mtDNA sequence variation was examined by using hypervariable segment I (HVSI) sequencing and restriction analysis of the haplogroup-specific sites in 325 individuals representing 5 Russian populations from the European part of Russia. The Y-chromosome variation was investigated in 338 individuals from 8 Russian populations (including 5 populations analyzed for mtDNA variation) using 12 binary markers. For both uniparental systems most of the observed haplogroups fell into major West Eurasian haplogroups (97.9% and 99.7% for mtDNA and Y-chromosome haplogroups, respectively). Multidimensional scaling analysis based on pairwise F(ST) values between mtDNA HVSI sequences in Russians compared to other European populations revealed a considerable heterogeneity of Russian populations; populations from the southern and western parts of Russia are separated from eastern and northern populations. Meanwhile, the multidimensional scaling analysis based on Y-chromosome haplogroup F(ST) values demonstrates that the Russian gene pool is close to central-eastern European populations, with a much higher similarity to the Baltic and Finno-Ugric male pools from northern European Russia. This discrepancy in the depth of penetration of mtDNA and Y-chromosome lineages characteristic for the most southwestern Russian populations into the east and north of eastern Europe appears to indicate that Russian colonization of the northeastern territories might have been accomplished mainly by males rather than by females.     

Evolutionarily singular strategies and the adaptive growth and branching of the evolutionary tree

We present a general framework for modelling adaptive trait dynamics in which we integrate various concepts and techniques from modern ESS-theory. The concept of evolutionarily singular strategies is introduced as a generalization of the ESS-concept. We give a full classification of the singular strategies in terms of ESS-stability, convergence stability, the ability of the singular strategy to invade other populations if initially rare itself, and the possibility of protected dimorphisms occurring within the singular strategy's neighbourhood. Of particular interest is a type of singular strategy that is an evolutionary attractor from a great distance, but once in its neighbourhood a population becomes dimorphic and undergoes disruptive selection leading to evolutionary branching. Modelling the adaptive growth and branching of the evolutionary tree can thus be considered as a major application of the framework. A haploid version of Levene's soft selection model is developed as a specific example to demonstrate evolutionary dynamics and branching in monomorphic and polymorphic populations.     

Distinguishing features of immature stages of Panchaetothripinae (Thysanoptera: Thripidae) known in New Zealand

Diagnostic morphological characters of the juvenile Panchaetothripinae in New Zealand are illustrated. Keys developed enable colonies with only immature stages to be identified without needing to rear adults. Live larvae or larvae in ethanol are distinguished by the presence of expanded tips of body setae (Parthenothrips dracaenae), the absence of setae at the abdomen tip (Hercinothrips bicinctus), setae at abdomen tip not longer than abdominal tip width (Heliothrips haemorrhoidalis) and abdominal tip setae longer than abdominal tip width (Sigmothrips aotearoana, endemic species). The presence or absence of spine-like setae on abdominal segments 9 and 10, and the number and length of setae on the wing buds, enable identification of pupae. Abdominal spine-like setae were on the prepupa and pupa of H. bicinctus and S. aotearoana, species that pupate off the plant, and are probably defensive structures. This is the first record of spine-like setae on segment 10 of terebrantian pupae.     

Enzymatic 7β hydroxylation of 4,4,10β-trimethyl-trans-decal-3β-ol (TMD)

4,4,10β-Trimethyl-trans-decal-3β-ol (TMD, 1), an inhibitor of 2,3-oxidosqualene cyclase, is converted by S₁₀ rat liver homogenate (RLH) to 4,4,10β-trimethyl-trans-decalin-3β,7β-diol (2) as its chief metabolite in 15 to 32% yield. Identification of 2 was accomplished by (a) gas-liquid chromatography/mass spectroscopy (GLC-MS) molecular-weight determination; (b) identity of GLC retention times with those of synthetic 2 and derived dione 15 on three columns; and (c) isotopic dilution and recrystallization to constant specific activity of both ³H-2 and its diacetate. Resolution of TMD was effected via formation of diastereomeric esters 18 and 19; and both d-TMD and l-TMD were found to be metabolized in RLH to 2, with d-TMD, the enantiomer having the nonsteroidal absolute configuration, being about twice as effectively hydroxylated.     

11个绵羊品种MSTN基因非翻译区的变异

利用PCR-RFLP技术对特克塞尔羊、夏洛莱羊、小尾寒羊、蒙古羊、乌珠穆沁羊、阿勒泰羊、呼伦贝尔羊、塔什库尔干羊、多浪羊、湖羊和岗巴羊11个品种的345个个体的肌肉生长抑制素(Myostatin, MSTN)基因非翻译区(UTR)的变异进行了多态性分析。结果表明大小为271 bp和1 003 bp的扩增片段经限制性内切酶MboⅡ和BsaⅠ酶切后表现多态, 经卡方检验所有品种在该基因座位均处于平衡状态(P>0.05), 3种基因型在11个绵羊品种中的分布差异极显著(P<0.01)。通过限制性内切酶HpyCH4Ⅳ 酶切实验, 证明我国9个地方绵羊品种不存在特克塞尔绵羊中发现的导致肌肉发达的SNP位点, 并在3′UTR区发现了个别碱基突变位点能够形成miRNA作用的靶基序, 测序表明3′UTR区的突变频率较高。     

抗菌肽对种植体周围炎主要致病菌生长抑制作用的研究

目的研究抗菌肽KSL及其衍生物KSL—W对种植体周围炎主要致病菌的体外抑菌效果。方法应用二倍稀释法检测KSL和KSL—W对血链球菌、具梭核杆菌和牙龈卟啉单胞菌的最小抑菌浓度（MIC）和最小杀菌浓度（MBC）;MTT法检测KSL和KSL—W对成骨样细胞MG-63的细胞毒性。结果KSL和KSL—W对具梭核杆菌的MIC和MBC分别为0．0156mg／mL和0．0313mg／mL,对牙龈卟啉单胞菌的MIC和MBC分别为0．125mg／mL和0．5mg／mL,在0．5mg／mL的浓度范围内对血链球菌没有抑制作用;KSL和KSL-W在0．5mg／mL的浓度范围内没有细胞毒性。结论KSL和KSL—W没有细胞毒性,对具梭核杆菌和牙龈卟啉单胞菌具有抑制作用。