孟德尔分离比9：3：3：1的4种演变

在孟德尔研究的豌豆7对等位基因与其控制的7对相对性状中,明显地表现出对应关系．在他所做的豌豆2对相对性状杂交实验中F2有4种表现型,分离比接近9:3:3:1。其实,这种现象在生物界并不是很多的．后来科学家们发现生物的性状往往不是简单地由1对等位基因决定,而是由多对等位基因相互作用的结果,在涉及2对等位基因的遗传杂交实验中,F2的表现型分离比9:3:3:1常常会发生以下几种演变。     

中国艳天牛属一新种：鞘翅目：天牛科：天牛亚科

中国艳天牛属一新种（鞘翅目：天牛科：天牛亚科）蒋书楠,陈力（西南农业大学植物保护系,四川省重庆市北碚６３０７１６）关键词天牛科,分类学,艳天牛属,新种天牛亚科艳天牛属ＡｃｒｏｃｙｒｔｉｄｕｓＪｏｒｄｏｎ的已知种类,可分为金色毛被种和银色毛被种两类。Ｊ...     

广头叶蝉属二新种：同翅目：叶蝉科：广头叶蝉亚科

本文记述采用自河南伏牛山区的广头叶蝉属Ｍａｃｒｏｐｓｉｓ Ｌｅｗｉｓ,１８３４二新种：旱柳广头叶蝉Ｍ．ｍａｔｓｕｄａｎｉｓ Ｗｅｉ ｅｔ Ｃａｉ,ｓｐ．ｎｏｖ．和大麻广头叶蝉Ｍ．ｃａｎｎａｂｉｓ Ｗｅｉ ｅｔ Ｃａｉ,ｓｐ,ｎｏｖ．模式标本保存在安徽农业大学。     

清明：天人合一

<正>清明节,兼具自然与人文两大内涵,既是二十四节气之一,也是传统祭祖节日。当太阳到达黄经15°时为清明节气,时间在4月4日或5日。《岁时百问》解释说：“万物生长此时,皆清洁而明净,故谓之清明。”天清气明,就是清明名称的由来。清明时节的习俗有很多,如踏青、放风筝、植树、扫墓祭祖、插柳等。作为二十四节气中的唯一国假,人们对清明的重视程度可见一斑。当然,清明时节在心理建设中的地位也是无可比拟的。     

昆明果蝇属一新种：双翅目：果蝇科

长鬃果蝇Drosophila(Drosophila)Iongisetae sp.nov.新种(图A—F) 体长:4.5mm,翅长4.0mm. 头部:复眼红色,具稀疏的微毛。触角第2节黄色,具2小刚毛,第3节棕黄色,触角芒上侧具3个分枝毛,下侧具1个分枝毛,末端分叉大、下颚须黄色,具2根鬃。额黄     

基因组学：重出江湖

二十世纪九十年代被认为是前基因组时代，微阵列的第一次商业化应用就是在九十年代中期。当2001年第一张人类基因组草图公开后，生物学突然进入了后基因组时代，有人提出基因组学已死的传闻并愈演愈烈。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.