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1.
The Status of the Race Concept in Physical Anthropology   总被引:2,自引:1,他引:1  
There are hereditary differences among human beings. Some of these differences have geographical correlates. Some genetic variants that produce physical or behavioral deficits occur significantly more often in some areas, or in some ethnic groups, than in others. However, none of these facts provides any intellectual support for the race concept, for racial classifications, or for social hierarchies based on ethnic-group membership.
The geographical element of the race concept is important in theory but is widely ignored in practice since it does not conform well to the facts of current human phenotype distribution. Much of the literature on supposed racial differences involves such geographically meaningless exercises as studying differences among "races" by subdividing a sample of North Americans. If races are defined as geographically delimited conspecific populations characterized by distinctive regional phenotypes, then human races do not exist now and have not existed for centuries,  相似文献   

2.
1995年10月至1997年11月,在美国阿肯色大学水稻研究推广中心,用水稻品种LA110和Jasmine-85与水稻品种Teqing、Katy、Mars、LaGrue和Newbonnet进行不完全双列杂交,对其杂交后代和亲本用美国3个主要稻瘟病菌小种(以下简称小种)IB-33、IB-45和IE-1进行接种鉴定和遗传分析研究.结果表明:亲本LA110、Jasmine-85、Teqing抗所有3个小种.Katy抗小种IB-45和IE-1,感小种IB-33.Mars抗小种IE-1,感小种IB-33和IB-45.LaGrue感所有3个小种.Newbonnet抗小种IB-45,感小种IB-33和IE-1.所有抗病亲本的抗病基因,其F1分别对相应小种呈现显性抗病性.抗病亲本杂交,LA110与Jasmine-85对小种IB-33,LA110与Teqing、Jasmine-85对小种IE-1,及Jasmine-85与Teqing对小种IE-1,是等位的抗病基因.LA110与Teqing对小种IB-33,及Jasmine-85与Teqing对小种IB-33,分别存在三对独立遗传的显性抗病基因.LA110与Teqing、Katy、Newbonnet、Jasmine-85对小种IB-45,Jasmine-85与Teqing、Katy、Newbonnet对小种IB-45,LA110与Katy、Mars对小种IE-1,Jasmine-85与Katy、Mars对小种IE-1,分别存在两对独立遗传的显性抗性基因.抗病亲本LA110或Jasmine-85与感病亲本Mars对小种IB-33,抗病亲本LA110与感病亲本Mars对小种IB-45,具有两对显性互补抗病基因,当两对显性抗病基因同时存在时,表现出抗性.抗病亲本LA110或Jasmine-85与感病亲本Katy、LaGrue、Newbonnet对小种IB-33,抗病亲本LA110与感病亲本LaGrue对小种IB-45,抗病亲本Jasmine-85与感病亲本Mars、LaGrue对小种IB-45,抗病亲本LA110或Jasmine-85与感病亲本LaGrue、Newbonnet对小种IE-1,分别存在一对显性抗病基因.两个亲本正、反交的遗传表现一致.本文也讨论了LA110、Teqing和Jasmine-85三个抗病品种在美国水稻抗病育种中利用的可能性.  相似文献   

3.
Progeny from single females of four known races of Heterodera glycines Ichinohe were used to establish relatively uniform populations. Single females from these populations were mated with males of other races in all possible combinations to study compatibility and inheritance patterns. When race 1 or 3 was crossed with either race 2 or 4, there was a significant reduction in number of females and a greater number of eggless females than in crosses of races 1 × 3 and 2 × 4. More females matured and fewer were eggless when matings were of the same race. Parasitic capabilities of races 2 and 4 were dominant or partially dominant over those of races 1 and 3, based on parasitism of F₁ hybrids. Segregation patterns were generally similar for reciprocal crosses between races. There appeared to be either one or two major genes segregating for parasitism of ''Pickett'' soybean in the different crosses. A hybrid isolate (race 3 × 4) that differed in parasitic capability from the four known races produced as many females on the resistant soybean genotype, PI 90,763, as on the susceptible Lee cultivar. Those data indicate that isolates of H. glycines with a different parasitic capability may develop from gene recombination.  相似文献   

4.
D Bai  D R Knott 《Génome》1994,37(3):405-409
Six accessions of Triticum turgidum var. dicoccoides L. (4x, AABB) of diverse origin were tested with 10 races of leaf rust (Puccinia recondita f.sp. tritici Rob. ex Desm.) and 10 races of stem rust (P. graminis f.sp. tritici Eriks. &Henn.). Their infection type patterns were all different from those of lines carrying the Lr or Sr genes on the A or B genome chromosomes with the same races. The unique reaction patterns are probably controlled by genes for leaf rust or stem rust resistance that have not been previously identified. The six dicoccoides accessions were crossed with leaf rust susceptible RL6089 durum wheat and stem rust susceptible 'Kubanka' durum wheat to determine the inheritance of resistance. They were also crossed in diallel to see whether they carried common genes. Seedlings of F1, F2, and BC1F2 generations from the crosses of the dicoccoides accessions with RL6089 were tested with leaf rust race 15 and those from the crosses with 'Kubanka' were tested with stem rust race 15B-1. The F2 populations from the diallel crosses were tested with both races. The data from the crosses with the susceptible durum wheats showed that resistance to leaf rust race 15 and stem rust race 15B-1 in each of the six dicoccoides accessions is conferred by a single dominant or partially dominant gene. In the diallel crosses, the dominance of resistance appeared to be affected by different genetic backgrounds. With one exception, the accessions carry different resistance genes: CI7181 and PI 197483 carry a common gene for resistance to leaf rust race 15. Thus, wild emmer wheat has considerable genetic diversity for rust resistance and is a promising source of new rust resistance genes for cultivated wheats.  相似文献   

5.
Forty-three accessions of Phaseolus vulgaris and four of P. coccineus were classified on the basis of the reaction of their primary leaves and pods to inoculation with races 1 and 2 of the pathogen Pseudomonas phaseolicola. Four groups were recognised, (1) highly resistant to race 1 only, (2) resistant to both races, (3) slightly resistant to both races or (4) susceptible to both races. Race 1 resistance was present in a number of accessions (e.g. Red Mexican UI3, Rona, Cornell 42–242). Resistance to race 1 and 2 was present in PI 150414, GN Nebraska No. 1 sel. 27, OSU 10183 and other accessions with PI 150414 in their parentage. Studies on the inheritance of resistance in Red Mexican UI3 and PI 150414 were made in crosses with various susceptible bean cultivars. A single dominant factor was responsible for race 1 resistance in Red Mexican UI3. The resistance factor in PI 150414 to races 1 and 2 behaved as a recessive in crosses with Cascade and Seafarer but was partially dominant in crosses with Gallatin 50. These findings suggest that genetic background can influence the expression of the resistance factor from PI 150414 and largely reconcile the conflicting evidence of previous investigators.  相似文献   

6.
Genetic variation in the synthesis of halogenated secondary metabolites in the Japanese marine red alga Laurencia nipponica Yamada (Rhodomelaceae, Ceramiales) has been investigated in laboratory crossing experiments and chemical analyses, F1 tetrasporophytes and F1 gametophytes resulting from crosses within chemical races produced major metabolites characteristic of these races. F1 tetrasporophytes derived from reciprocal interracial crosses produced: (i) both parental types of secondary metabolites; (ii) either of the parental types; or (iii) a further major compound in addition to both parental types or in addition to either of the parental types. The latter cases suggest that hybrid-specific products were formed by the combined enzymatic complements of the parents, as F1 gametophytes derived from these interracial F1 tetrasporophytes yielded one or other of their parental products in an approximate 1:1 ratio. The population structure was analyzed at localities in Hokkaido, where two of the chemical races occur sympatrically. At Usujiri (Minami-kayabe), where the prepacifenol race and the laureatin race were sym-patric, hybrid gametophytes (recombination type) were found in high frequency in addition to hybrid tetra sporophytes, which strongly suggests that a new, pre-pacifenol/laureatm race is beginning to be produced by natural hybridization and recombination. By contrast, at Oshoro Bay, where the laurencin race and the epi-lauraliene race grew together, the interracial hybrids were rare: only a few tetrasporophytes (probably F1 generation) were found, suggesting that racial integrity may be retained by habitat segregation and/or the absence of recombination-type gametophytes.  相似文献   

7.
Phenological differences between host plants can contribute to allochronic isolation of host races of phytophagous insects. Host races of the gallmaking fly, Eurosta solidaginis, that live on different species of goldenrod (Solidago altissima and S. gigantea) exhibit different emergence phenologies. These differences could result from adaptation to corresponding phenological differences between the hosts in periods of optimal suitability for gall formation and survival to adulthood. In order to test this, some flies of each host race were allowed to emerge naturally while the emergence times of others were manipulated to correspond to the emergence and oviposition periods of the other host race. Percent gall formation and survival to adulthood were examined for three oviposition periods: the peak time of emergence and oviposition of the earlier-emerging host race (that from S. gigantea), that of the later-emerging host race (that from S. altissima), and a week after the peak emergence of the host race from S. altissima. Flies of both host races were allowed to ovipuncture plants of the appropriate species during each of these periods. Plant relative growth rates were measured during each of these periods. The experiment was repeated twice over a two-year period. Relative growth rates of both host species were highest during the earliest oviposition period (the period during which the host race from S. gigantea normally emerges). Percent gall formation was significantly correlated with plant relative growth rate, but the coefficient of determination was low. In both years of the study, percent gall formation of both host races was highest during the earliest oviposition period (the period during which the host race from S. gigantea normally oviposits). Likewise, percent survival to adulthood in both host races was highest during the earliest oviposition period. There was no significant effect of oviposition period on the percent of larval death due to parasitism by Eurytoma gigantea or predation by Mordellistena unicolor. These results suggest that the host race from S. altissima does not emerge at the time that its host is optimally suited for gall formation or survival to adulthood. Therefore, differences in emergence phenologies do not appear to be due to corresponding phenological differences between the host species in suitability for gall formation or survival to adulthood.  相似文献   

8.
No correlation was found between virulence of races and their prevalence, although races which attacked one or two genes for resistence only constituted more than 71% of the isolates studied. Differences in race prevalence were not associated with their incubation or latent period. Uredospore germination of races differing in virulence indicated that a race of narrow virulence and wide prevalence germinated better over a wider range of temperature than races of higher virulence and showed better germ tube elongation at extreme temperatures. These factors may be in part responsible for the wider prevalence of some races.  相似文献   

9.
The results of experimental hybridisation between some chromosome subraces belonging to the X0 and XY chromosome races of the brachypterous grasshopper P. sapporensis are presented. Pre-zygotic reproductive isolation mechanisms in experimental pairs were not confirmed. In crossings of XY-standard x X0-standard and XY-standard x X0-Naganuma chromosome subraces, a zygotic barrier has been found. All embryos of XY-standard x X0-standard crosses and the vast majority of embryos of XY-standard x X0-Naganuma crosses were obtained from female diploid or haploid/diploid cells as a result of parthenogenesis. In very rare cases, when the zygotic barriers had been surmounted, normal embryo heterozygotes and a F1 hybrid generation were obtained in XY-standard x X0-Naganuma crosses. On the contrary, crosses between the XY-Tanno and X0-standard subraces gave viable offspring in spite of many chromosome differences such as a X-A translocation and fixed pericentric inversions in four pairs of autosomes. The results obtained do not support the hypothesis that chromosomal differences play a key role in restricting gene flow between X0 and XY races of P. sapporensis. The presence of crossing barriers explains the phenomena of the purity of the X0 and XY chromosomes races.  相似文献   

10.
D Bai  G J Scoles  D R Knott 《Génome》1994,37(3):410-418
Six accessions of Triticum triaristatum (Willd) Godr. &Gren. (syn. Aegilops triaristata) (6x, UUMMUnUn), having good resistance to both leaf rust (Puccinia recondita f.sp. tritici Rob. ex Desm) races and stem rust (P. graminis f.sp. tritici Eriks. &Henn.) races, were successfully crossed with both susceptible durum wheats (T. turgidum var. durum L., 2n = 28, AABB) and bread wheats (T. aestivum, 2n = 42, AABBDD). In some crosses, embryo rescue was necessary. The T. triaristatum resistance was expressed in all F1 hybrids. Backcrossing of the F1 hybrids to their wheat parents to produce BC1F1 plants was more difficult (seed set 0-7.14%) than to produce F1 hybrids (seed set 12.50-78.33%). The low female fertility of the F1 hybrids was due to low chromosome pairing. Only gametes with complete or nearly complete genomes from the F1 hybrids were viable. In BC2F4 populations from the cross MP/Ata2//2*MP, monosomic or disomic addition lines (2n = 21 II + 1 I or 22 II) with resistance to leaf rust race 15 (IT 1) were selected. In BC2F2 populations from the crosses CS/Ata4//2*MP and MP/Ata4//2*MP, monosomic or disomic addition lines with resistance to either leaf rust race 15 or stem rust race 15B-1 (both IT 1) were selected. Rust tests and cytology on the progeny of the disomic addition lines confirmed that the genes for rust resistance were located on the added T. triaristatum chromosomes. The homoeologous groups of the T. triaristatum chromosomes in the addition lines from the crosses MP/Ata2//2*MP, CS/Ata4//2*MP, and MP/Ata4//2*MP were determined to be 5, 2, and 7, respectively, through the detecting of RFLPs among genomes using a set of homoeologous group specific wheat cDNA probes. The addition lines with resistance to leaf rust race 15 from the crosses MP/Ata2//2*MP and CS/Ata4//2*MP were resistant to another nine races of leaf rust and the addition line with resistance to stem rust race 15B-1 from the cross MP/Ata4//2*MP was resistant to another nine races of stem rust as were their T. triaristatum parents. Since such genes provide resistance against a wide spectrum of rust races they should be very valuable in wheat breeding for rust resistance.  相似文献   

11.
12.
Mimetic colour pattern races of Heliconius butterflies provide a striking example of adaptive radiation and numerous crossing experiments have investigated the genetics of these racial differences. However, colour pattern differentiation between closely related Heliconius species has not been previously studied. Here we present data from crosses between H. erato cyrbia and its sister species, H. himera. The genetic architecture underlying colour pattern divergence between these species is identical to that observed between races of H. erato. As in inter-racial crosses, colour pattern differences resulted from segregation at a few major loci. Evidence from 1321 offspring in 4 F1, 17 backcross, 7 F2 and 21 further crosses showed that two major loci controlled most of the colour pattern differences between H. erato and H. himera. There were strong interactions between these loci in their patterns of expression and evidence for other loci with relatively minor phenotypic effects. More importantly, based on patterns of expression within broods and linkage with Aconitase, we conclude that these major loci were homologous with those known to be responsible for colour pattern differences within H. erato. Our crosses also permit a re-evaluation of the relationships between colour pattern races of H. erato. This suggests that H. e. hydara, which occurs across a major mtDNA break, is the ancestral phenotype from which other races have evolved. Based on this assumption, we find no evidence to support the recent suggestion that apparently homologous colour pattern alleles have arisen multiple times.  相似文献   

13.
The Australian rodent, Uromys caudimaculatus, consists of two chromosome races, a) The Southern Race is characterized by the possession of two to twelve B-chromosomes. These vary considerably in size, morphology, and C- and G-banding characteristics, they behave as univalent at meiosis and are inherited in a random manner, b) The Northern Race lacks Bchromosomes, but possesses large blocks of distal C-positive heterochromatin on between 18 and 28 of the 46 chromosomes. The C-blocks may be entirely G-positive, entirely G-negative, or G-banded, suggesting heterogeneity within the C-blocks. There is extensive variation both between and within populations of the northern race in the number and size of the distal heterochromatic blocks. There is no apparent difference between the races in chiasma frequency. The northern race does have a much higher proportion of interstitial versus distal chiasmata, although it is probable that this is merely a reflection of lack of crossing over in the heterochromatic blocks rather than an actual shift of chiasma localisation within the euchromatin. Despite the extensive differences between the races in the amount and organization of constitutive heterochromatin, hybrids show no abnormalities at meiosis and they are fully fertile.  相似文献   

14.
Cultivated common bean germplasm is especially diverse due to the parallel domestication of two genepools in the Mesoamerican and Andean centers of diversity and introgression between these gene pools. Classification into morphological races has helped to provide a framework for utilization of this cultivated germplasm. Meanwhile, core collections along with molecular markers are useful tools for organizing and analyzing representative sets of these genotypes. In this study, we evaluated 604 accessions from the CIAT core germplasm collection representing wide genetic variability from both primary and secondary centers of diversity with a newly developed, fluorescent microsatellite marker set of 36 genomic and gene-based SSRs to determine molecular diversity and with seed protein analysis to determine phaseolin alleles. The entire collection could be divided into two genepools and five predominant races with the division between the Mesoamerica race and the Durango–Jalisco group showing strong support within the Mesoamerican genepool and the Nueva Granada and Peru races showing less diversity overall and some between-group admixture within the Andean genepool. The Chile race could not be distinguished within the Andean genepool but there was support for the Guatemala race within the Mesoamerican genepool and this race was unique in its high level of diversity and distance from other Mesoamerican races. Based on this population structure, significant associations were found between SSR loci and seed size characteristics, some on the same linkage group as the phaseolin locus, which previously had been associated with seed size, or in other regions of the genome. In conclusion, this study has shown that common bean has very significant population structure that can help guide the construction of genetic crosses that maximize diversity as well as serving as a basis for additional association studies.  相似文献   

15.
A host race is a population that is partially reproductively isolated from other conspecific populations as a direct consequence of adaptation to a specific host. The initial step in host race formation is the establishment of genetically based polymorphisms in, for example, morphology, preference, or performance. In this study we investigated whether polymorphisms observed in Galerucella nymphaeae have a genetic component. Galerucella nymphaeae, the water lily leaf beetle, is a herbivore which feeds and oviposits on the plant hosts Nuphar lutea and Nymphaea alba (both Nymphaeaceae) and Rumex hydrolapathum and Polygonum amphibium (both Polygonaceae). A full reciprocal crossing scheme (16 crosses, each replicated 10 times) and subsequent transplantation of 1,001 egg clutches revealed a genetic basis for differences in body length and mandibular width. The heritability value of these traits, based on midparent-offspring regression, ranged between 0.53 and 0.83 for the different diets. Offspring from Nymphaeaceae parents were on average 12% larger and had on average 18% larger mandibles than offspring from Polygonaceae parents. Furthermore, highly significant correlations were found between feeding preference of the offspring and the feeding preference of their parents. Finally, two fitness components were measured: development time and survival. Development time was influenced by diet, survival both by cross type and diet, the latter of which suggest adaptation of the beetles. This suggestion is strengthened by a highly significant cross x diet interaction effect for development time as well as for survival, which is generally believed to indicate local adaptation. Although no absolute genetic incompatibility among putative host races was observed, survival of the between-host family offspring, on each diet separately, was lower than the survival of the within-host family offspring on that particular host. Survival of offspring of two Nymphaeaceae parents was about two times higher on Nymphaeaceae than on Polygonaceae, whereas survival of offspring of two Polygonaceae parents was 11 times higher on Polygonaceae than on Nymphaeaceae (based on untransformed data). Based on these results, we conclude that genetically determined polymorphisms in morphology and feeding preference exist in G. nymphaeae, resulting in differential performance. Furthermore, in each diet separately, offspring of between-host family crosses were less fit than offspring of within-host family crosses. These results support the hypothesis that within this species two host races can be distinguished.  相似文献   

16.
In this paper I begin by arguing that there are significant intellectual and normative continuities between pre-Victorian hereditarianism and later Victorian eugenical ideologies. Notions of mental heredity and of the dangers of transmitting hereditary ‘taints’ were already serious concerns among medical practitioners and laymen in the early nineteenth century. I then show how the Victorian period witnessed an increasing tendency for these traditional concerns about hereditary transmission and the integrity of bloodlines to be projected onto the level of national health. Tracing the gradual emergence of eugenical thought, I also highlight some of the more fundamental social, political and intellectual factors that promoted this predilection for extrapolating from the individual lineage to the nation and race. In doing so I argue that fully fledged eugenical thought was always unlikely to emerge prior to the early Victorian period. However, I am also able to show that Francis Galton's 1865 eugenical proposals were far from innovative and that identifying him as the ‘father’ of the eugenics movement is highly misleading.  相似文献   

17.
This paper considers how an idea of the Australian Aborigine impacted upon the development of racial thinking throughout the nineteenth century. We distinguish three phases of this development. Against the background of what was considered to be a distinctly human capacity to rise above nature, our central argument however is that the extreme and irremediable savagery attributed to the Aborigine led to the mid‐nineteenth shift to a polygenist, or an innatist, idea of race. The first part of our discussion, covering the early 1800s, elicits a specifically humanist puzzlement at the unimproved condition of the Aborigines. But, as we will show in the central part of our discussion, it was not only the Aborigines' inclination but their capacity for ‘improvement’ that came to be doubted. Challenging the very basis upon which ‘the human’ had been defined, and the unity of humankind assumed, the Aborigine could not be accommodated within a prevailing conception of racial difference as a mere variety of the human. The elaboration of polygenism may therefore be understood as arising out of this humanist incomprehension: as an attempt to account for the ontologically inexplicable difference of the Australian Aborigine. In the final part of our discussion, we trace the legacy of the Aborigine's place within polygenism through the evolutionary thought of the late nineteenth century. Despite an explicit return to monogenism, here the Aborigine is invoked to support the claim that race constitutes a more or less permanent difference and, for certain races, a more or less permanent deficiency. And as, in these terms, the anomalous Aborigine became an anachronism, so Australia's indigenous peoples came to embody the most devastating conclusion of evolutionary thought: that in the human struggle for existence certain races were destined not even to survive.  相似文献   

18.
Two important new books by Greg Carter and Kenneth Prewitt provide detailed historical perspectives on how understandings of race and race categories have evolved since the founding of the republic. Prewitt focuses on an analysis of racial classification in the US census – the so-called ‘statistical races’ –and its changing role in US policy, culminating in recommendations for radical change. Carter takes as his theme population mixing across the races, offering a positive, even celebratory, but little known account of the moments and movements that have praised mixing. As pressures mount on the ‘statistical races’ in the late twentieth century, Prewitt uses the political space opened up by these debates to offer fundamental changes to US methods of ethno-racial data collection, including the removal of these questions from the census. The jury is in recess for further deliberations.  相似文献   

19.
The evolution of selfing from outcrossing is a common transition, yet little is known about the mutations and selective factors that promote this shift. In the mustard family, single-locus self-incompatibility (SI) enforces outcrossing. In this study, we test whether mutations causing self-compatibility (SC) are linked to the self-incompatibility locus (S-locus) in Leavenworthia alabamica, a species where two selfing races (a2 and a4) co-occur with outcrossing populations. We also infer the ecological circumstances associated with origins of selfing using molecular sequence data. Genealogical reconstruction of the Lal2 locus, the putative ortholog of the SRK locus, showed that both selfing races are fixed for one of two different S-linked Lal2 sequences, whereas outcrossing populations harbor many S-alleles. Hybrid crosses demonstrated that S-linked mutations cause SC in each selfing race. These results strongly suggest two origins of selfing in this species, a result supported by population admixture analysis of 16 microsatellite loci and by a population tree built from eight nuclear loci. One selfing race (a4) shows signs of a severe population bottleneck, suggesting that reproductive assurance might have caused the evolution of selfing in this case. In contrast, the population size of race a2 cannot be distinguished from that of outcrossing populations after correcting for differences in selfing rates. Coalescent-based analyses suggest a relatively old origin of selfing in the a4 race (~150 ka ago), whereas selfing evolved recently in the a2 race (~12-48 ka ago). These results imply that S-locus mutations have triggered two recent shifts to selfing in L. alabamica, but that these transitions are not always associated with a severe population bottleneck, suggesting that factors other than reproductive assurance may play a role in its evolution.  相似文献   

20.
ABSTRACT  Significant differences in views on race (once a core anthropological concept) occur between scientists from different countries. In light of the ongoing race debate, we present the concept's current status in Europe. On three occasions in 2002–03, we surveyed European anthropologists' opinions toward the biological race concept. The participants were asked whether they agreed that there are biological races within the species Homo sapiens . A dependence was sought between the type of response and several factors. Three of these factors—country of academic education, discipline, and age—were found to be significant in differentiating the replies. Respondents educated in Western Europe, physical anthropologists, and middle-aged persons reject race more frequently than respondents educated in Eastern Europe, people in other branches of science, and those from both younger and older generations. The survey shows that the views of anthropologists on race are sociopolitically (ideologically) influenced and highly dependent on education. [Keywords: human races, race concept, physical anthropology, Europe]  相似文献   

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