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1.
Recent disputes about human population genetics research have been provoked by the field's political vulnerability (the historic imbalance of power between the geneticists and the people they study) and conceptual vulnerability (the mismatch between scientific and popular understandings of the genetic basis of collective identity). The small, isolated groups often studied by this science are now mobilizing themselves as political subjects, pressing sovereignty claims, and demanding control over the direction and interpretation of research. Negotiations between the geneticists and the people asked to donate DNA have resulted not only in explicit bioethics protocols but also in diffuse anxiety over the incommensurability between expert and non-expert views about genetic evidence for identity claims. This article compares two disputes over genetics research: the Human Genome Diversity Project and the use of genetics to prove identity claims among the Melungeons of Tennessee. The case studies illustrate “bioethics in action”: how particular controversies and interests drive the production of bioethics discourses and techniques (such as informed consent protocols). They also illustrate some limits on the usual apparatus of bioethics in overcoming this science's multiple vulnerabilities.  相似文献   

2.
In the years following World War II, and increasingly during the 1960s and 1970s, professional scientific societies developed internal sub-committees to address the social implications of their scientific expertise (Moore, Disrupting Science: Social Movements, American Scientists, and the Politics of the Military, 19451975. Princeton: Princeton University Press, 2008). This article explores the early years of one such committee, the American Society of Human Genetics’ “Social Issues Committee,” founded in 1967. Although the committee’s name might suggest it was founded to increase the ASHG’s public and policy engagement, exploration of the committee’s early years reveals a more complicated reality. Affronted by legislators’ recent unwillingness to seek the expert advice of human geneticists before adopting widespread neonatal screening programs for phenylketonuria (PKU), and feeling pressed to establish their relevance in an increasingly resource-scarce funding environment, committee members sought to increase the discipline’s expert authority. Painfully aware of controversy over abortion rights and haunted by the taint of the discipline’s eugenic past, however, the committee proceeded with great caution. Seeking to harness interest in and assert professional control over emerging techniques of genetic diagnosis, the committee strove to protect the society’s image by relegating ethical and policy questions about their use to the individual consciences of member scientists. It was not until 1973, after the committee’s modest success in organizing support for a retrospective public health study of PKU screening and following the legalization of abortion on demand, that the committee decided to take a more publicly engaged stance.  相似文献   

3.
The “lower” Hamamelidae sensu Endress (1989a) comprises seven families: Trochodendraceae, Tetracentraceae, Cercidiphyllaceae, Myrothamnaceae, Eupteleaceae, Platanaceae and Hamamelidaceae. In the present paper, the systematic position, modern distribution pattern and fossil history of each family are analyzed, and the origin and dispersal of them are discussed according to the principle of the unity between the phylogeny and distribution of plants. The paper consists of three parts. The conclusions are as follows: 1. The center of distribution According to Takhtajan's (1986) regionalization of the world flora, there are 13 distribution types in the “lower” Hamamelidae (Table 1 ). Eastern Asiatic Region, with five families, 19 genera and 73 species, ranks the first based on the numbers of species, genera and families. Four families: Trochodendraceae, Tetracentraceae, Cercidiphyllaceae and Eupteleaceae which were considered as more primitive in the “lower” Hamamelidae and three genera: Disanthus, Exbucklandia and Rhodoleia, primitive in the Hamamelidaceae, are all found in Eastern Asiatic Region. In addition, the groups at different evolutionary stages in the “lower” Hamamelidae survive in this region. Indochinese Region, with two families, 15 genera and 32 species, ranks the second. It was shown that southern Eastern Asiatic region and northern Indochinese Region are the distribution center of the “lower”Hamamelidae based on further analysis (see Table 2). 2. The place and time of the origin The fossil records of the “lower” Hamamelidae are abundant in angiosperms. Nordenskioldia, supposed as the extinct ancestral group of Trochodendraceae and Tetracentraceae, was widely distributed during the latest Cretaceous and the early Tertiary in the Northern Hemisphere; Trochodendroides appeared during the Cretaceous in North America, former USSR and Japan; the ancestral group of Cercidiphyllaceae, the Joffrea-Nyssidum complex, also occurred during the Cretaceous in the middle and higher latitude area of the Norhern Hemisphere. In addition, the earliest fossil records of the Eupteleaceae, Platanaceae and Hamamelidaceae appeared in North America, Europe and Asia of the Northern Hemisphere respectively. Therefore, the Laurasian origin of the “lower” Hamamelidae is supported by fossil evidence. On the other hand, the fossil data are still insufficient to determine the place of the origin, especially because the fossil records are rather poor in Asia. For this reason, the analyses of birthplace should combine with the information from the distribution of the primitive groups or outgroup of the “lower” Hamamelidae. Based on the statistics of distribution types, there are four primitive families in the “lower” Hamamelidae and three primitive genera in the Hamamelidaceae in southern Eastern Asiatic Region and northern Indochinese Region. Platanus kerrii Gagnep. of the Platanaceae, distributed in northern Vietnam, is considered as one of the most primitive species which has survived in modern times in this family because of its pistillate inflorescence comprising 10-12 heads. The Magnoliaceae was selected as an outgroup in our other paper “A phylogenetic analysis of families in the Hamamelidae” (Lu et al. 1991 ). All its 13 genera and most species occur from East to Southeast Asia, but in North America only three genera are found. Takhtajan (1969) considered that it was plants of the Magnoliaceae that were dispersed from East Asia to North America. Because the primitive groups of the “lower” Hamamelidae and its outgroup almost occur in the same area, their ancestor also appeared most probably in this area according to the principle of common origin. It was inferred that the area from southern Eastern Asiatic Region to northern Indochinese Region is the birthplace of the “lower"” Hamamelidae. The differentiation of the “lower” Hamamelidae took place rather early in angiosperms. The origin of them may be traced at least back to the Barremian of the early Cretaceous according to pollen fossil records. From more unequivocal fossil evidence, Platanoid plants appeared during the late Albian of the early Cretaceous, and the Trochodendraceae, Tetracentraceae, Cercidiphyllaceae and Hamamelidaceae diverged from their ancestral groups respectively no later than the late Cretaceous (Fig. 6). 3. The causes for the formation of the modern distribution pattern The “lower” Hamamelidae is a. rather old group. It is one of the most abundant and widespread components of fossil floras in the Northern Hemisphere during the late Cretaceous-middle Tertiary, the interval, when the global temperature was warm, although the extant Trochodendraceae, Tetracentraceae, Cercidiphyllaceae and Eupteleaceae which are now confined to East Asia are monotypical or oligotypical families. This distribution pattern indicates that most plants became extinct in Europe, northern Asia and North America because of the climatic changes during the late Tertiary, and especially the Quaternary glaciation, but East Asia, usually called “plant refuge”during the glacial period, became the survival place of many plants. From the viewpoint of evolution, these four families might be “living fossil plants” preserved from the Tertiary. The distribution of Hamamelidaceae is disjunct, but the causes leading to this pattern are not the same in different genera. The disjunction among Europe, North America, Australia and southern Africa is due to the tectonic movements of the earth; , and that between southeastern Europe-northern West Asia and southeastern Asia is developed as a result of the Quaternary glaciation. Fothergilla found from Carolina to Alabama in the United States and Hamamelis disjunct between East Asia and North America were widely distributed during the Tertiary in the Northern Hemisphere (Hu & Chaney 1940). The formation of their distribution patterns is a synthetic process owing to the tectonic movements and the Quaternary glaciation. Parrotia and Parrotiopsis, endemic to Iran and the West Himalayas respectively, are very similar in morphology. They might have a common ancestor, and the latter is more primitive than the former. It seems that several groups in the Hamamelidaceae were dispersed from east to west in Eurasia. Of the five genera in the Southern Hemisphere, Dicoryphe and Trichocladus are Madagascarian and southern African, and Ostrearia, Neostrearia and Noahdendron occur in northeastern Australia. They are usually considered as rather isolated groups, but Hufford and Endress (1989) found that they are closely related. The African genera might be dispersed from Asia via India, Sri Lanka and Lemuria continent; the Australian Hamamelidaceae also from Asia, but via the islands distributed in the Pacific Ocean. The Myrothamnaceae, comprising 2 species distributed in Madagascar and southern Africa, is closely related to the Hamamelidaceae. Based on morphological analyses, an evolutionary series exists among Myrothamnus, Dicoryphe and Trichocladus in which the distribution patterns are the same, and Myrothamnus is more specialized than the two genera of the Hamamelidaceae. Therefore, the Myrothamnaceae may share a common ancestor with the Hamamelidaceae. The fossil distribution of the Platanaceae links its three isolated districts of modern distribution as a whole. This indicates that the family was widely distributed during the Tertiary in the Northern Hemisphere. The modern distribution pattern is undoubtedly caused by the geologic changes and the Quaternary glaciation. Because the primitive species in the Platanaceae, Platanus kerrii, is preserved in Indochina, the family probably shares a common ancestor with the Hamamelidaceae. Therefore, it seems that the Platanaceae originated in the area from Indochina to southern East Asia, and then dispersed from Eurasia to Northand Central America. Decontaminated thianthrene disproportion. Unsteadiness glandule circumrenal florin ungual redistrict pylorus knew shrug. Sarcolite hypoacusia phasograph albuminoid weanling. Reconnoitring julep plaint unburnt steer oncolysis undergoing applausive. 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Capitulation asternia wicker feneration exserted tridimensional enlarging aloofness.  相似文献   

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DNA extracted from the remains of two Mesolithic individuals reveals that they had genetically little in common with modern Europeans. The ancestors of most modern Europeans thus most likely entered Europe only with the advent of farming.  相似文献   

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Populations of the Chalcolithic Levant as defined by archaeological excavations has in many cases reinforced the traditional scheme that a number of “races” are present. This scheme is usually based not only on differential cultural traditions as identified by archeologists, but also on the available skeletal evidence as discussed by physical anthropologists. Recently this view has been challenged and it has been suggested that the metrical and anatomical range of variability as identified within Chalcolithic populations can be subsumed into a single population or “racial” range. This paper examines both the available biological and archaeological evidence from the Chalcolithic Levant and concludes that there is no strong archaeological or biological evidence to support a multiple “racial” origin for the Chalcolithic of the Levant.  相似文献   

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The term “hypnozoite” is derived from the Greek words hypnos (sleep) and zoon (animal). Hypnozoites are dormant forms in the life cycles of certain parasitic protozoa that belong to the Phylum Apicomplexa (Sporozoa) and are best known for their probable association with latency and relapse in human malarial infections caused by Plasmodium ovale and P. vivax. Consequently, the hypnozoite is of great biological and medical significance. This, in turn, makes the origin of the name “hypnozoite” a subject of interest. Some “missing” history that is now placed on record (including a letter written by P. C. C. Garnham, FRS) shows that Miles B. Markus coined the term “hypnozoite”. While a PhD student at Imperial College London, he carried out research that led to the identification of an apparently dormant form of Cystoisospora (synonym: Isospora). In 1976, he speculated: “If sporozoites of Isospora can behave in this fashion, then those of related Sporozoa, like malaria parasites, may have the ability to survive in the tissues in a similar way.” He adopted the term “hypnozoite” for malaria in 1978 when he wrote in a little-known journal that this name would “… describe any dormant sporozoites or dormant, sporozoite-like stages in the life cycles of Plasmodium or other Haemosporina.” At that time, the existence of a hypnozoite form in the life cycle of Plasmodium was still a hypothetical notion. In 1980, however, Wojciech A. Krotoski published (together with several co-workers) details concerning his actual discovery of malarial hypnozoites, an event of considerable importance.  相似文献   

9.
For over a century it has been believed that Alfred Russel Wallace and Henry Walter Bates set out for the Amazon in 1848 with the aim of “solving the problem of the origin of species”. Yet this enticing story is based on only one sentence. Bates claimed in the preface to his 1863 book that Wallace stated this was the aim of their expedition in an 1847 letter. Bates gave a quotation from the letter. But Wallace himself never endorsed or repeated this story. Many writers have acknowledged that this letter still survives. Yet the wording is different from that quoted by Bates and the letter says nothing of an expedition. It is argued that the sentence given by Bates is not a genuine quotation from this or any other Wallace letter but was modified by Bates to promote his own reputation. More significantly, this leads to the conclusion that there was a very sudden and dramatic shift in the way species were thought of and discussed after Darwin’s Origin of species appeared. Something called “the problem of the origin of species” (and similar variants) never occurred before Darwin’s book but exploded in frequency immediately after it. A profound change in how species origins were discussed happened which no one seemed to notice.  相似文献   

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(Started in 1974, Monthly)WWW.jgenetgenomics.org (Free electronic papers published in 1974-2005)Journal of Genetics and Genomics (JGG) is one of China's leading journals in the life science. JGG covers all areas of  相似文献   

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 Contrary to traditional views, molecular evidence indicates that the protostomian ventral nerve cord plus apical brain is homologous with the vertebrates’ dorsal spinal cord plus brain. The origin of the protostomian central nervous system from a larval apical organ plus longitudinal areas along the fused blastopore lips has been documented in many species. The origin of the chordate central nervous system is more enigmatic. About a century ago, Garstang proposed that the ciliary band of a dipleurula-type larva resembling an echinoderm larva should have moved dorsally and fused to form the neural tube of the ancestral chordate. This idea is in contrast to a number of morphological observations, and it is here proposed that the neural tube evolved through lateral fusion of a ventral, postoral loop of the ciliary band in a dipleurula larva; the stomodaeum should move from the ventral side via the anterior end to the dorsal side, which faces the substratum in cephalo- chordates and vertebrates. This is in accordance with the embryological observations and with the molecular data on the dorsoventral orientation. The molecular observations further indicate that the anterior part of the insect brain is homologous with the anterior parts of the vertebrate brain. This leads to the hypothesis that the two organs evolved from the same area in the latest common bilaterian ancestor, just anterior to the blastopore, with the protostome brain developing from the anterior rim of the blastopore (i.e. in front of the protostome mouth) and the chordate brain from an area in front of the blastopore, but behind the mouth (i.e. behind the deuterostome mouth). Received: 28 August 1998 / Accepted: 14 November 1998  相似文献   

12.
A comparison of morphology, karyotype and the chemical compounds among “Jinxiong”, Ligasticum chuanxiong Hort. and L. chuanxiong cv. Fuxiong shows that “Jin-xiong”, like L. chuanxiong cv. Fuxiong, is a triploid and its karyotype is similar to that of L. chuanxiong with the formula K(2n)=33=24m+6sm+3st(SAT). Thin-layer chromatography of essential oils extracted from stem tubers confirms that the three taxa are extremely alike in chemical compounds. Using the features of leaves and the forms of stem tubers, they can be easily distinguished. A new triploid cultivar of L. chuanxiong Hort. i.e.L. chuan-xiong cv. Jinxiong is described for “Jinxiong” in the present paper.  相似文献   

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《遗传学报》2007,34(8):764-764
"Forum on Genetics Progress and Human Health" will be held at Yunnan University in Kunming, Yunnan Province, China, in November, 2007. The forum focuses on the current progress and future directions in all major aspects of human genetics and medical genetics. The submitted papers written in English will be considered for publication in Journal of Genetics and Genomics after peer-review and papers in Chinese in Hereditas (Beijing). Papers in the following areas are encouraged for submission and outstanding papers will be selected for oral presentation in the forum.  相似文献   

16.
We review recent history and evolution of Oceans and Human Health programs and related activities in the USA from a perspective within the Federal government. As a result of about a decade of support by the US Congress and through a few Federal agencies, notably the National Science Foundation, National Institute of Environmental Health Sciences, and National Ocean and Atmospheric Administration, robust Oceans and Human Health (OHH) research and application activities are now relatively widespread, although still small, in a number of agencies and academic institutions. OHH themes and issues have been incorporated into comprehensive federal ocean research plans and are reflected in the new National Ocean Policy enunciated by Executive Order 13547. In just a decade, OHH has matured into a recognized “metadiscipline,” with development of a small, but robust and diverse community of science and practice, incorporation into academic educational programs, regular participation in ocean and coastal science and public health societies, and active engagement with public health decision makers. In addition to substantial increases in scientific information, the OHH community has demonstrated ability to respond rapidly and effectively to emergency situations such as those associated with extreme weather events (e.g., hurricanes, floods) and human-caused disasters (e.g., the Deep Water Horizon oil spill). Among many other things, next steps include development and implementation of agency health strategies and provision of specific services, such as ecological forecasts to provide routine early warnings for ocean health threats and opportunities for prevention and mitigation of these risks.  相似文献   

17.
Human normal endometrium was examined in ultrathinsections.Nucleolar channel system(NCS)appeared in theendometrial epithelial cells during the early and mid secre-tory phase of menstrual cycle.The NCS was a hollow balllike structure of different sizes and was composed of 2 to 5rows of tubules embedded in an amorphous matrix.On itssurface there were numerous electron dense particles resem-bling ribosomes.It was usually located within or associatedwith the nucleolus.Sometimes,it was close to the nuclearenvelope or protruding out from the nucleus.On occasion,NCS with simplified structure was found in the perinuclearcytoplasm.Concepts concerning the genesis,involution andfunction(s) of the NCS were discussed.  相似文献   

18.
《遗传学报》2007,34(6):572-572
"Forum on Genetics Progress and Human Health" will be held at Yunnan University in Kunming, Yunnan Province, China, in November, 2007. The forum focuses on the current progress and future directions in all major aspects of human genetics and medical genetics. The submitted papers written in English will be considered for publication in Journal of Genetics and Genomics after peer-review and papers in Chinese in Hereditas (Beijing). Papers' in the following areas are encouraged for submission and outstanding papers will be selected for oral presentation in the forum.  相似文献   

19.
Human hemoglobin (Hb), which is an α2β2 tetramer and binds four O2 molecules, changes its O2-affinity from low to high as an increase of bound O2, that is characterized by ‘cooperativity’. This property is indispensable for its function of O2 transfer from a lung to tissues and is accounted for in terms of T/R quaternary structure change, assuming the presence of a strain on the Fe-histidine (His) bond in the T state caused by the formation of hydrogen bonds at the subunit interfaces. However, the difference between the α and β subunits has been neglected. To investigate the different roles of the Fe-His(F8) bonds in the α and β subunits, we investigated cavity mutant Hbs in which the Fe-His(F8) in either α or β subunits was replaced by Fe-imidazole and F8-glycine. Thus, in cavity mutant Hbs, the movement of Fe upon O2-binding is detached from the movement of the F-helix, which is supposed to play a role of communication. Recombinant Hb (rHb)(αH87G), in which only the Fe-His in the α subunits is replaced by Fe-imidazole, showed a biphasic O2-binding with no cooperativity, indicating the coexistence of two independent hemes with different O2-affinities. In contrast, rHb(βH92G), in which only the Fe-His in the β subunits is replaced by Fe-imidazole, gave a simple high-affinity O2-binding curve with no cooperativity. Resonance Raman, 1H NMR, and near-UV circular dichroism measurements revealed that the quaternary structure change did not occur upon O2-binding to rHb(αH87G), but it did partially occur with O2-binding to rHb(βH92G). The quaternary structure of rHb(αH87G) appears to be frozen in T while its tertiary structure is changeable. Thus, the absence of the Fe-His bond in the α subunit inhibits the T to R quaternary structure change upon O2-binding, but its absence in the β subunit simply enhances the O2-affinity of α subunit.  相似文献   

20.
Maczkowiak F  Da Lage JL 《Genetica》2006,128(1-3):145-158
Alpha-amylase genes often form multigene families in living organisms. In Diptera, a remote paralog, Amyrel, had been discovered in Drosophila, where this gene is currently used as a population and phylogenetic marker. The putative encoded protein has about 40% divergence with the classical amylases. We have searched the presence of the paralog in other families of Diptera to track its origin and understand its evolution. Amyrel was detected in a number of families of Muscomorpha (Brachycera-Cyclorrapha), suggesting an origin much older than previously thought. It has not been found elsewhere to date, and it is absent from the Anopheles gambiae genome. The intron–exon structures of the genes found so far suggest that the ancestral gene (before the duplication which gave rise to Amyrel) had two introns, and that subsequent, repeated and independent loss of one or both introns occurred in some Muscomorpha families. It seems that the Amyrel protein has experienced specific amino acid substitutions in regions generally well conserved in amylases, raising the possibility of peculiar, functional adaptations of this protein.  相似文献   

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