Australopithecus garhi: a new species of early hominid from Ethiopia

The lack of an adequate hominid fossil record in eastern Africa between 2 and 3 million years ago (Ma) has hampered investigations of early hominid phylogeny. Discovery of 2.5 Ma hominid cranial and dental remains from the Hata beds of Ethiopia's Middle Awash allows recognition of a new species of Australopithecus. This species is descended from Australopithecus afarensis and is a candidate ancestor for early Homo. Contemporary postcranial remains feature a derived humanlike humeral/femoral ratio and an apelike upper arm-to-lower arm ratio.     

Triassic vertebrates of gondwanan aspect from the richmond basin of virginia

A new locality of early Late Triassic age in the Richmond basin of east-central Virginia has yielded abundant remains of a diversified assemblage of small to medium-sized tetrapods that closely resembles Southern Hemisphere (Gondwanan) assemblages in the predominance of certain synapsids. Associated palynomorphs indicate an early middle Carnian age for the fossiliferous strata. The discovery suggests that previously recognized differences between tetrapod assemblages of early Late Triassic age from Gondwana and Laurasia at least in part reflect differences in stratigraphic age, rather than geographic separation.     

Evolutionary genetics. Europeans trace ancestry to Paleolithic people

Y chromosome data show that living Europeans have deep roots in the region--and researchers say genetic markers may be linked to cultures known from archaeological remains. In a report on page 1155, an international team reports that a wealth of data from the Y chromosome show that more than 80% of European men have inherited their Y chromosomes--which are transmitted only from father to son--from Paleolithic ancestors who lived 25,000 to 40,000 years ago. Thus, the genetic template for European men was set as early as 40,000 years ago, then modified--but not recast--by the Neolithic farmers who arrived in the region about 10,000 years ago.     

Basal anthropoids from Egypt and the antiquity of Africa's higher primate radiation

Early anthropoid evolution in Afro-Arabia is poorly documented, with only a few isolated teeth known from before approximately 35 million years ago. Here we describe craniodental remains of the primitive anthropoid Biretia from approximately 37-million-year-old rocks in Egypt. Biretia is unique among early anthropoids in exhibiting evidence for nocturnality, but derived dental features shared with younger parapithecids draw this genus, and possibly >45-million-year-old Algeripithecus, into a morphologically and behaviorally diverse parapithecoid clade of great antiquity.     

Early human cultural and skeletal remains from guitarrero cave, northern peru

An early man site in highland Peru yielded a rich cultural assemblage in stratigraphic association with faunal remains, botanical remains, and campfire remnants that furnished secure radiocarbon dates. A human mandible and teeth, showing interesting patterns of occlusal wear, were found in a stratum dated by a charcoal sample to 10,610 B.C., the oldest such date in South America.     

Pelagic fishing at 42,000 years before the present and the maritime skills of modern humans

By 50,000 years ago, it is clear that modern humans were capable of long-distance sea travel as they colonized Australia. However, evidence for advanced maritime skills, and for fishing in particular, is rare before the terminal Pleistocene/early Holocene. Here we report remains of a variety of pelagic and other fish species dating to 42,000 years before the present from Jerimalai shelter in East Timor, as well as the earliest definite evidence for fishhook manufacture in the world. Capturing pelagic fish such as tuna requires high levels of planning and complex maritime technology. The evidence implies that the inhabitants were fishing in the deep sea.     

贵州发现的早期稻作遗存及谷物的收割和加工

贵州中水遗址近年来发现了大量的炭化稻谷遗存,它们与临省发现的稻谷品种不同,可能是属于适合当地高原环境、在本土生长的稻谷品种。贵州出土的早期农具中,石刀和杵臼的数量较多：其中石刀类型多样,是主要的谷物收割工具;杵臼形制简单,是主要的谷物脱壳工具。岜沙苗族人的现代生活场景是古代谷物收割、加工方式的最好诠释。     

Chromosomal and nucleolar RNA synthesis in root tips during mitosis

Comparative rates of RNA synthesis in chromatin and nucleolar fractions during mitosis in root-tip cells of Allium and Nigella were studied by pulse-labeling of cells with tritiated cytidine. Although the rate of RNA synthesis decreases in the condensing chromosomes during prophase, it remains normal in the nucleolar fraction as long as nucleoli are maintained. RNA synthesis stops in mitotic cells lacking distinct nucleoli. In the late telophase or very early interphase cells, RNA synthesis resumes at a faster rate in the pronucleolar bodies than in the chromatin.     

气候条件限制下的人类活动——全新世早中期中国栽培水稻分布的变化对气候变迁的响应

水稻栽培是新石器时代重要的人类活动之一,其发展同气候之间的联系是研究稻作起源和文明发展的一个关键问题。该文利用搜集到的全新世早中期(12 000～5 500 aBP)中国的栽培水稻出土遗址点数据,对全新世早中期中国水稻栽培同气候的关系进行了分析。结果表明,栽培水稻的起源与初期发展具有"边缘效应",即分布于野生稻分布的边缘地带;而其早期的发展和分布也具有类似的特征,即主要受气候因素的影响,因此全新世早中期栽培水稻的分布范围的变化受到气候条件的限制,该时期环境变化受气候"主导"。     

修饰回交法在陆地棉育种中的作用

1988年,选择丰产、优质及抗病的棉花品种,分别设置了丰优和丰抗两组试验。丰优组3个试验分别在江浦和徐州两地,丰抗组2个试验在盐城和徐州两地进行。结果表明,修饰回交群体比对照增产7.47%～91.5%;也比回交、复交、双交及单交群体增产,且大多数达显著水平。修饰回交能同步提高陆地棉的皮棉产量与比强度、早熟性或抗枯萎病性,并在改变上述经济性状间的负相关方面表现了优于回交、复交、双交和单交的效应。这表明陆地棉经济性状间的负相关主要是由基因连锁导致的,由一因多效引起的可能性很小。应用修饰回交法培育丰优和丰抗的新品种具有良好的前景,本课题组用此法育成的丰优新品系已开始试种。     

An aptian plant with attached leaves and flowers: implications for angiosperm origin

Recent phylogenetic studies and fossil finds support a new view of the ancestral angiosperm. A diminutive fossil angiosperm from the Aptian of Australia has attached leaves, with intermediate pinnate-palmate, low-rank venation, and lateral axes bearing pistillate organs subtended by bracts and bracteoles that are the oldest direct evidence of flowers. A variety of data suggests a similar morphology for the ancestral angiosperm. This hypothesis explains similarities between rhizomatous to herbaceous Magnoliidae and basal monocots, scarcity of early agniosperm wood, and lack of recognition of earlier remains.     

An Early Cretaceous tribosphenic mammal and metatherian evolution

Derived features of a new boreosphenidan mammal from the Lower Cretaceous Yixian Formation of China suggest that it has a closer relationship to metatherians (including extant marsupials) than to eutherians (including extant placentals). This fossil dates to 125 million years ago and extends the record of marsupial relatives with skeletal remains by 50 million years. It also has many foot structures known only from climbing and tree-living extant mammals, suggesting that early crown therians exploited diverse niches. New data from this fossil support the view that Asia was likely the center for the diversification of the earliest metatherians and eutherians during the Early Cretaceous.     

小河西文化生业模式初探

小河西文化是西辽河流域新石器时代较早阶段的文化遗存。通过对小河西文化的气候与环境、聚落、生产生活工具、动植物遗存和原始农业的分析来看,小河西文化的生业模式以渔猎采集为主,辅之以简单的农业为补充,其原始农业已经处于萌芽阶段。     

Early Adaptive Radiation of Birds: Evidence from Fossils from Northeastern China

Late Jurassic and Early Cretaceous birds from northeastern China, including many complete skeletons of Confuciusornis, provide evidence for a fundamental dichotomy in the class Aves that may antedate the temporal occurrence of the Late Jurassic Archaeopteryx. The abundance of Confuciusornis may provide evidence of avian social behavior. Jurassic skeletal remains of an ornithurine bird lend further support to the idea of an early separation of the line that gave rise to modern birds. Chaoyangia, an ornithurine bird from the Early Cretaceous of China, has premaxillary teeth.     

套袋对茄果类蔬菜品质和产量的影响

采用田间对比试验,研究了套袋措施对早春露地茄子和番茄农药残留及品质的影响。结果表明:套袋能有效防止害虫对露地茄子和番茄果实的直接为害,减少农药使用次数,降低产品农药残留,并改善果实外观色泽,提高产品的商品性能和生产效益。     

Rapid extinction of the moas (Aves: Dinornithiformes): model, test, and implications

A Leslie matrix population model supported by carbon-14 dating of early occupation layers lacking moa remains suggests that human hunting and habitat destruction drove the 11 species of moa to extinction less than 100 years after Polynesian settlement of New Zealand. The rapid extinction contrasts with models that envisage several centuries of exploitation.     

辣椒疫霉菌在土壤中消长动态研究

为有效防治辣椒疫霉病，对辣椒疫霉病田土壤进行了病菌分离、菌株配对培养、越冬存活形式等研究。结果表明：病田土壤中的疫霉菌数量有明显的季节性变化。以5-8月最多，冬季和初春最少；湖南长沙地区疫霉菌的配对型有A2和A1A2两种类型，多以卵孢子形态在土壤中越冬；病田土壤和植物病残体是辣椒疫霉病最主要的初侵染源。     

牙鲆早期发育和变态期间Pitx2基因的表达

Pitx2基因被认为是脊椎动物中调节内脏器官左右不对称的关键转录因子。为进一步探讨牙鲆变态期间的左右不对称是否也受Pitx2的左特异活性调节,采用逆转录聚合酶链式反应(RT-PCR),拟在变态的牙鲆的头部组织中克隆编码Pitx2基因的部分cDNA序列,并通过以18s rRNA为内标的半定量RT-PCR研究其在牙鲆早期发育和变态期间的表达情况。克隆和测序的结果表明Pitx2在牙鲆早期发育和变态期间也存在基因表达;而半定量的结果表明它的左特异性功能很可能在变态的早期阶段发挥作用。但是,牙鲆变态期间的右眼移动是否受Pitx2的左特异活性调控,以及变态期间的左右不对称和内脏器官的左右不对称是否拥有相同的分子机制,仍需进一步研究。     

牙鲆早期发育和变态期间Pitx2基因的表达(英文)

Pitx2基因被认为是脊椎动物中调节内脏器官左右不对称的关键转录因子。为进一步探讨牙鲆变态期间的左右不对称是否也受Pitx2的左特异活性调节,采用逆转录聚合酶链式反应(RT-PCR),拟在变态的牙鲆的头部组织中克隆编码Pitx2基因的部分cDNA序列,并通过以18s rRNA为内标的半定量RT-PCR研究其在牙鲆早期发育和变态期间的表达情况。克隆和测序的结果表明Pitx2在牙鲆早期发育和变态期间也存在基因表达;而半定量的结果表明它的左特异性功能很可能在变态的早期阶段发挥作用。但是,牙鲆变态期间的右眼移动是否受Pitx2的左特异活性调控,以及变态期间的左右不对称和内脏器官的左右不对称是否拥有相同的分子机制,仍需进一步研究。     

A Reassessment of Astraspis desiderata, the Oldest North American Vertebrate

The fossil evidence for the early evolution of vertebrates consists of the remains of agnathans, jawless vertebrates, from the Ordovician of Australia, North America, and Bolivia. Because of the fragmentary nature of the material, it has not been possible to reconstruct these animals sufficiently well to understand their relation to each other and to later vertebrates. Though two genera have been known from the Harding Sandstone of North America since 1892, there are still only three articulated specimens known, two of Astraspis desiderata and one of Eriptychius americanus. The most recently found specimen of Astraspis was reexamined and found to show the orbit, a series of eight branchial openings and a complete tail, structures hitherto undescribed in any Ordovician vertebrate. A reconstruction ofAstraspis shows, on the basis of the series of branchial openings, that it is a primitive craniate and not a heterostracan as previously thought.