CHINA AS A CENTER FOR EARLY ANIMAL DOMESTICATION

The paleontological as well as the archeological record in China is unique in that there is adequate evidence of hominid association with most of the animals that we know today as domesticates beginning at very early dates. During the last few years advances have been made with studies of the dog, horse, camel,water buffalo, cattle,yak,sheep, goat, pig, and chicken in China. One drawback is that by the time most domestic animals can be dated by recorded history they are quite advanced as domesticates and are quite similar osteologicaly to their modern counterparts.     

Domestication rates in wild-type wheats and barley under primitive cultivation

Man's first cereal crops were sown from seed gathered from wild stands, and it was in the course of cultivation that domestication occurred. This paper prcsents thr preliminary rrsults of an experimcntal approach to the measurement of domestication rate in crops of wild-type einkorn wheat exposed to primitive systems of husbandry. The results indicate that in wild-type crops of einkorn, emmer and barley (a) domestication will have occurred only if they were harvested in a partially ripe (or near-ripe) state using specific harvesting methods; (b) exposure to shifting cultivation may also have been required in somr cases; and (c) given these requirements, the crops could have become completely domcsticated within two centuries, and maybe in as little as 20–30 years without any form of conscious selection. This paper (1) considers the possible length of delays in the start of domestication due to early crops of wild-type cereals lacking domestic-type mutants; (2) examines the combination of primitive husbandry practices that would have been necessary for any selective advantage to have been unconsciously conferred on these mutants; (3) considers the state of ripeness (at harvest) necessary for crops to be able to respond to these selective prcssures; (4) outlines field measurements of the selective intensities (selection coefficients) which arise when analogous husbandry practices are applied experimentally to living wild-type crops; (5) summarizes the essential features of a mathematical model which incorporatcs these measurements of selection coefficients and other key variables, and which describes the rate of increasc in domestic-type mutants that would have occurred in early populations of wild-type cereals under specific combinations of primitive husbandry practices; (6) considers why very early cultivators should have used that combination of husbandry methods which, we suggest, unconsciously brought about the domestication of wild wheats and barley; and (7) concludes by considering whether these events arc likely to have left recognizable traces in archaeological remains.     

Heredity and genetic mapping of domestication-related traits in a temperate japonica weedy rice

Rice is often found as various weedy forms in temperate or newly cultivated rice growing regions throughout the world. The emergence of these forms in the absence of true wild rice remains unclear. A genetic analysis of domestication-related traits (weed syndrome) has been conducted to better understand the appearance of these plants in rice fields. A doubled haploid (DH) population was derived from a cross between a japonica variety and a weedy plant collected in Camargue (France) to set up a genetic linkage map consisting of 68 SSR and 31 AFLP loci. Five qualitative traits related to pigmentation of different organs and 15 developmental and morphological quantitative traits were scored for genes and QTLs mapping. Despite a good reactivity in anther culture and a high fertility of the DH lines, segregation distortions were observed on chromosomal segments bearing gametophytic and sterility genes and corresponded to various QTLs evidenced in indica×japonica distant crosses. Mapping of the coloration genes was found to be in agreement with the presence of several genes previously identified and according to the genetic model governing the synthesis and distribution of anthocyan pigment in the plant. In addition, the main specific traits of weedy forms revealed the same genes/QTLs as progeny derived from a cross between Oryza sativa and its wild progenitor O. rufipogon. A large variation for most characters was found in the DH population, including transgressive variation. Significant correlations were observed between morphology and traits related to weeds and corresponded to a distinct colocalization of most of the QTLs on a limited number of chromosomal regions. The significance of these results on the origin of weedy forms and the de-domestication process is discussed. Received: 25 February 2000 / Accepted: 14 April 2000     

Differentiation in seed germination among populations of Capsicum annuum along a latitudinal gradient in Mexico

Toinvestigate variation in germination capability of wild Capsicumannuum seeds, the effects of light, fluctuating temperature,gibberellic acid (GA), soaking and sulfuric acid were analyzed in samples from14 populations from northwest Mexico. Germination was inhibited by darkness inall populations studied. Darkness inhibition of germination was overcome byfluctuating temperature and GA, factors which also increased germinationpercentage but not germination rate. Soaking treatments did not significantlyincrease germination of C. annuum seeds, while sulfuricacid treatments had negative effects on the process. Populations showed highvariation in germination response in all treatments, except for continuousdarkness. Principal component analysis differentiated some populations withhighgermination percentage and slow germination rate. Such differences did notcorrelate with climatic variables from collection sites. Given the variation ingermination patterns observed, some of these totally contrasting, we have to becautious when considering the results of studies based on a single wildpopulation.     

Cell number counts - The fw2.2 and CNR genes and implications for controlling plant fruit and organ size

Two key determinants of plant and organ size are cell number and cell size, and altering either one may affect the plant organ size, but cell number control often plays a predominant role in natural populations. Domesticated crops usually have larger fruit and harvested organ sizes than wild progenitors. Crop yields have increased significantly by breeding, often via heterosis, which is associated with increased plant and organ size primarily achieved by cell number increases. A small class of genes is now known that control plant and organ sizes though cell number or cell size. The fw2.2 gene was found to control a major QTL for tomato fruit size by negatively affecting cell numbers. Orthologs to these fw2.2 genes underlie QTLs for fruit sizes in other species, and their expression can be negatively correlated with increased cell number. In maize decreased or increased expression of the fw2.2 ortholog ZmCNR1, increases or decreases cell number, respectively, thereby affecting maize organ size throughout the plant and thus also whole plant size. Therefore, these genes should now be considered as more general regulators of plant cell number and organ size. The exact molecular function of these transmembrane domain proteins remains unknown, as does any clear relationship to the cell cycle. Because these genes control organ sizes in diverse plants and important crop species, and because they can affect whole plant size, interest arose into how effects of such genes could parallel agronomic crop improvements, in particular that by heterosis, as it also affects cell number. In joining these subjects here in discussion we speculate on how single gene cell number regulation and heterosis may cooperate in crop improvement.     

Domestication and stress effects on contrafreeloading and spatial learning performance in red jungle fowl (Gallus gallus) and White Leghorn layers

White Leghorn layers (WL) show modified foraging strategies, compared to their ancestor, the red jungle fowl (RJF). Birds selected for high production may invest more resources into production traits and less in other biological processes. This may affect the capacity to adapt to new or variable environments.Thirty birds of each of RJF and WL were raised in a stressful environment (unpredictable light:dark schedule) and 30 control animals of each breed in similar pens, but on a 12:12 h light:dark schedule. We studied the differences between breed and treatment with respect to contrafreeloading (CFL), spatial learning ability and the birds’ behaviour in a T-maze.WL showed less CFL, were less cautious in the test arena and showed an impaired spatial learning ability compared with RJF in both test situations. Stress impaired spatial learning in both breeds, but stressed RJF showed a more active response to the test situation than non-stressed RJF, by starting to eat faster, while stressed WL prolonged their time to start eating compared to non-stressed WL.Our results may reflect different adaptive strategies, where RJF appear better adapted to an unpredictable environment.     

Examining Usage to Ensure Utility: Co-Design of a Tool for Fall Prevention

Ambient Assisted Living (AAL) technologies can play an important role in helping elderly people achieve healthy ageing and maintain their autonomy. The balance quality tester (BQT) is a device for remote assessment of balance quality for older people at risk of falling. It has been validated both from a technical and a clinical perspective. However, for the BQT to be considered as a useful tool for long-term home monitoring of people with balance impairments, two issues are at stake: ease-of-use on a regular basis and trust in the validity of the data acquisition. To ensure this utility, a usage study has been made to understand the needs and values of different stakeholders: elders at risk of falling and their entourage, as well as health professionals. One main insight was the need to redesign the BQT, so as to fit the needs concerning ease-of-use and trust in validity of data acquisition. Using a Human-centred and Participatory Design approach, the redesigning work relates to hardware design, interaction design, interface design, and most of all to standardizing the protocol of stepping-on the BQT. This paper describes the main results, i.e. the design recommendations, and discusses the collaborative and iterative design process, which allowed the successful redesign of the BQT.     

Genomic insight into the divergence and adaptive potential of a forgotten landrace G. hirsutum L. purpurascens

Wild progenitors are an excellent source for strengthening the genetic basis and accumulation of desirable variation lost because of directional selection and adaptation in modern cultivars. Here, we re-evaluate a landrace of Gossypium hirsutum, formerly known as Gossypium purpurascens. Our study seeks to understand the genomic structure, variation, and breeding potential of this landrace, providing potential insights into the biogeographic history and genomic changes likely associated with domestication. A core set of accessions, including current varieties, obsolete accessions, G. purpurascens, and other geographical landraces, are subjected to genotyping along with multilocation phenotyping. Population fixation statistics suggests a marked differentiation between G. purpurascens and three other groups, emphasizing the divergent genomic behavior of G. purpurascens. Phylogenetic analysis establishes the primitive nature of G. purpurascens, identifying it as a vital source of functional variation, the inclusion of which in the upland cotton(cultivated G. hirsutum) gene pool may broaden the genetic basis of modern cultivars. Genome-wide association results indicate multiple loci associated with domestication regions corresponding to flowering and fiber quality. Moreover, the conserved nature of G. purpurascens can also provide insights into the evolutionary process of G. hirsutum.     

树鼩驯养繁殖实验动物标准及丙型肝炎动物模型技术平台建设的探讨

目前用于生物医学研究的树鼩大多数来源于野生捕获,由于个体间的差异较大,其实验结果的均匀性和可重复性较差,亟待解决树鼩人工饲养设施条件、繁殖关键技术、动物质量标准等一系列基础科学问题。许多文献报道了树鼩与其他实验动物比较,在肝病研究中具有巨大的开发应用潜力,在丙型肝炎动物模型研究中,亟待解决丙型肝炎病毒(HCV)细胞培养体系、HCV病毒感染剂量与感染途径、HCV病毒对树鼩体外、体内感染后病毒核酸检测、抗体检测和病理检测等技术方法的建立及动物模型评价标准问题。本文就上述问题系统性地进行初步报道,旨在为树鼩早日实现实验动物化和丙型肝炎疾病研究中应用提供科学依据。