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1.
Five hundred families from five different endogamous populations encompassing the main social rank in the caste hierarchy of the same geographical area of West Bengal, India, were analyzed to present variation in qualitative pattern types on fingers and palms. Sex dimorphism, homogeneous in all populations, suggests common characteristics of dermatoglyphic patterns. The pattern types are not uniformly distributed on 10 fingers and palmar configurational areas. However, most of these observations are homogeneous in nature, in both sexes among 5 populations. But the two sets of results on fingers and palms are not exactly the same. Palmar dermatoglyphic relationship reflects the better caste affinities, perhaps due to embryological development, having relatively a longer growth period compared to fingers (Cummins 1929). The present findings indicate that the qualitative dermatoglyphic affinities conform to the known ethnohistorical background of these populations, which correspond also to the results of quantitative dermatoglyphics as well as serological and biochemical markers of these populations. These observations indicate that these population groups have a common genetic background and thus traditional grouping of Indian populations on the basis of caste hierarchy may not be a reflection of the genetic origin of the population. In dermatoglyphic affinities, both qualitative and quantitative traits therefore may be quite useful in tracing the ethnohistorical background of these populations.  相似文献   

2.
The incidence of finger pattern types and the pattern intensity distribution in a Spanish sample (417 males and 416 females) drawn from the geographical area of Tierra de Campos have been studied. Sexual and bilateral differences for both dermatoglyphic traits were explored by means of chi 2-test and Mann-Whitney U-test, showing significant differences in all cases, excepting the sexual difference between left hands for pattern intensity. Kolmogorov test for distribution normality showed that pattern intensity was not normally distributed, being the distributions right skewed because of the low frequency of classes with fewer triradii. The results obtained in Tierra de Campos were compared with those observed in other Spanish and Portuguese populations, showing more heterogeneity in the pattern types than in pattern intensity. This could imply that arches account for the main source of variation between populations. Moreover, pattern type frequencies and pattern intensity in Tierra de Campos are, as expected, within the variation ranges of Southeuropean-Mediterranean populations and Caucasians as a whole, although the incidence of radial loops is located in the lower extremes of the corresponding variation ranges.  相似文献   

3.
In an area of the Jurassic mountains of Switzerland ecological aspects of the tick species Ixodes ricinus were studied. In particular, the influence of temperature, humidity and vegetation parameters on tick density and distribution were investigated several times in six different habitat types. This was carried out on two scales; on a small scale, within a habitat type and on a larger scale, where all six habitat types were included. By a marking experiment, aspects of the migration dynamics of the ticks were studied. The densities of the six habitat types differed significantly in most of the cases. An analysis of the distribution pattern within a habitat type showed a contagious distribution mostly for the forests and the forest edge, whereas a random distribution was found as well, mainly for the meadows. But these distribution patterns tend towards randomness with time. On a small scale none of the factors showed an influence on tick distribution, therefore the most important factor on this scale might be the hosts of Ixodes ricinus. On a larger scale, temperature and humidity do in some cases influence tick densities. The marking experiment suggests an extremely high turnover of the ticks in an area with an average host density, probably due to passive transportation by hosts and to activation of resting individuals.  相似文献   

4.
Various constructed ridge count phenotypes were studied in two endogamous populations from peninsular India. Heritabilities were estimated for five summed pattern ridge count traits: fingers and toes together; palms and soles together; fingers and palms together (manus); toes and soles together (pes); and fingers, palms, toes and soles together, defined as the total ridge count in man. In general, these phenotypes were found to he highly heritable, with the summed ridge counts for fingers and toes, and total ridge count showing almost Complete determination by additive polygenes. Total manus and pes pattern counts are less heritable. Little or no uterine environmental effects were detected for any of these phenotypes.  相似文献   

5.
Geographic variation in vocalizations is widespread in passerine birds, but its origins and maintenance remain unclear. One hypothesis to explain this variation is that it is associated with geographic isolation among populations and therefore should follow a vicariant pattern similar to that typically found in neutral genetic markers. Alternatively, if environmental selection strongly influences vocalizations, then genetic divergence and vocal divergence may be disassociated. This study compared genetic divergence derived from 11 microsatellite markers with a metric of phenotypic divergence derived from male bower advertisement calls. Data were obtained from 16 populations throughout the entire distribution of the satin bowerbird, an Australian wet-forest-restricted passerine. There was no relationship between call divergence and genetic divergence, similar to most other studies on birds with learned vocalizations. Genetic divergence followed a vicariant model of evolution, with the differentiation of isolated populations and isolation-by-distance among continuous populations. Previous work on Ptilonorhynchus violaceus has shown that advertisement call structure is strongly influenced by the acoustic environment of different habitats. Divergence in vocalizations among genetically related populations in different habitats indicates that satin bowerbirds match their vocalizations to the environment in which they live, despite the homogenizing influence of gene flow. In combination with convergence of vocalizations among genetically divergent populations occurring in the same habitat, this shows the overriding importance that habitat-related selection can have on the establishment and maintenance of variation in vocalizations.  相似文献   

6.
In a sample from the Biscaian Basque population, we studied the incidence of pattern types in fingers and the parallelism between the frequencies for the orientations of whorls (Wr, Ws, Wu) and the other pattern types (Lr, A, Lu). We reaffirm the importance of clarifying pattern types according to their orientation, which is of general use in the case of loops but less easily applied to whorls.  相似文献   

7.
以国家Ⅱ级保护极小种群野生植物——对开蕨(Phyllitis scolopendrium)为研究对象,分析了在海拔729、1008m群落内,其种群大小、分布频度和密度,个体形态特征指标及其在种群内、种群间差异,苗高分布规律、相对苗高组替代年龄级结构,分布格局和群落各层次的物种多样性,群落的相似性。结果表明:对开蕨在自然分布区内为偶见种,呈斑块状分布。在400m~2内,海拔1008m处(01群落)种群密度为31株,样地分布频度为43.75%,最大密度15株/25m~2;海拔729m处(02群落)种群密度为91株,样地分布频度为93.75%,最大密度30株/25m~2。通过对其自然苗高,叶片数量,有孢子囊叶片数量,最大叶片长、宽值,最小叶片长、宽值,冠径,叶片厚度7个形态指标的分析显示,种群内变异较大,随着植株高度(年龄)的增加,其变异系数均随之减小而趋于稳定;种群间在自然苗高,最大叶片长度和宽度,成熟孢子叶片数量,冠径,叶片厚度上达到极显著差异(P0.01)。其苗高分布呈现双峰型,01种群波谷出现在15.1—20.0cm处;02种群波谷出现在10.1—15.0cm处,两群落均显示有一次较大的更新过程,同时01种群在40.1—45.0cm出现间断。年龄级分析得出,01种群划分为5个龄级,近于正态分布;02种群划分为4个龄级,为倒J型分布;两种群分别处于中龄期和幼龄期,没有出现衰退型年龄结构。格局分析得出,对开蕨种群均为聚集分布。两群落的乔木、灌木、草本层的Shannon-Wiener指数、Pielou均匀度指数、Marglef丰富度指数、生态优势度和种间相遇机率较低(与地带顶级植被相比)而且分布不均;对开蕨在两群落的草本层中重要值较低,仅为伴生种。两群落相似性分析显示,乔木、灌木、草本层的相似度指数分别为66.67%、69.23%和38.46%,草本层差异较大。  相似文献   

8.
Liu YC  Milgroom MG 《Mycologia》2007,99(2):279-284
We found high diversity of vegetative compatibility (vc) types in native populations of the chestnut blight fungus, Cryphonectria parasitica, in Japan and China; almost every isolate was in a unique vc type. In Japan we found 71 vc types in a sample of 79 isolates pooled from six populations. Within two populations in China, all isolates (n=28 and 11) had unique vc types; we found 15 vc types among 25 isolates in a third Chinese population where multiple isolates were collected from some trees. None of the isolates from China and only three isolates in the 71 vc types from Japan were compatible with any of 64 vc type testers from Europe, which have known vegetative incompatibility genotypes. To our knowledge this is the first report of vc type diversity for C. parasitica in Japan or of any comparisons of vc types between Asia and Europe. The most significant result of this survey is the identification fungal isolates for expanding knowledge of the genetics of vegetative incompatibility.  相似文献   

9.
Qualitative finger and palmar dermatoglyphics of 547 individuals (293 males, 254 females) belonging to the Chuvashian population of Russia were studied to determine sexual dimorphism. The pattern types are not uniformly distributed on 10 fingers. Sex difference is homogeneous in all fingers whereas palmar patterns reflect the better sex variations for three palmar configurational areas (II, III, and IV). This is perhaps due to embryological development, having a relatively longer growth period compared with fingers (Cummins 1929). The present results of the Chuvashian population are not similar to the results of the five Indian populations of our previous study (Karmakar et al. 2002), perhaps due to a major ethnic difference.  相似文献   

10.
Twenty-one types of mtDNA were found in a survey of 39 Israeli Jews, of whom 18 were Sephardic and 21 Ashkenazic. The survey was made with six restriction enzymes that together recognize an average of 600 bp/genome. The differences among the types appear to be due to base substitution at 19 cleavage sites, one deletion, and one conformational mutation. The numbers of differences imply that these modern Jews stem from a minimum of 21 maternal lineages that were already distinct from one another 4,000-5,000 years ago. In three of the four cases where a type was found in more than one person, it occurred in both Ashkenazic and Sephardic populations. The diversity of types in the combined sample of two Jewish populations is lower than both that in a sample from various parts of Africa and that in a sample from various parts of East Asia. Nevertheless, it is as high as that in a sample from diverse parts of New Guinea, an area much larger than that in Israel to which the Jewish population traces back.  相似文献   

11.
水稻体细胞无性系R_1、R_2代中的雄性育性变异观察   总被引:11,自引:0,他引:11  
通过水稻幼穗培养,1991-1992两年间,在5个品种(珍汕97B、红源A、包源A、W6154s,和南广占)中共获得了50株雄性不育变异株,其中R_1代有48株,R_2代有2株。在R1代,共获得5268株再生植株,雄性不育变异的平均频率为0.91%(0.83-1.08%);在R_2代(珍汕97B)发生雄性不育变异的频率为2%。本文报道了多种花粉败育类型之间可以相互转变现象,此外不育和可育之间亦可以相互转变。对离体培养产生的雄性不育变异株用一批现有CMS(Cytoplasmicmalesterile)不育系的典型保持系、恢复系进行测交,结果表明,W6154s产生的雄性育性变异株仍保持核不育的特性;红源A产生的雄性育性变异株有的可能是嵌合体,有的其败育花粉类型虽发生了变化,但其恢保关系并没有改变,有的则可能已转成类似WA型的不育材料;南广占产生的典败变异株,其恢保关系类似WA型,可能属核不育转成CMS的首例发现。  相似文献   

12.
Numerous clones ofClosterium ehrenbergii Meneghini were isolated from soil or liquid samples from various localities and clonal uni-algal or axenic cultures were established. Mating types of these clones were determined by crossing with tester clones. No homothallic clone has been encountered, even in such an extensively surveyed area as that in Japan. By some unknown factors, mating type ratios have been found to deviate largely from 1∶1 in some populations in liquid samples, but not in populations from soil samples. Representative clones from each locality were intercrossed with those from other localities in all possible combinations. Seven reproductively isolated groups were recognized on the basis of capability and frequency of zygospore formation. Cooccurrence of more than two groups in the same sample has been encountered in five cases out of 41 localities surveyed. In four cases the two groups found together have turned out to be completely isolated but in the last case two groups of incomplete isolation were found with the other group of complete isolation.  相似文献   

13.
Two hundred and sixty-three Indians aged six and above were studied in Oklahoma for blood types, hemoglobin types, and physical traits; 53% were Seminoles and the remainder were admixed with Creek or other populations. The results indicate that they resemble the Florida Seminoles in most of their serologic traits. In physical traits they are comparable to the group studied by Krogman two decades ago. Compared with the Florida Seminoles, the Oklahoma sample are slightly taller and heavier, significantly lighter in skin color, and have a lower incidence of sickle cell gene. By both serology and morphology the Oklahoma group are most similar to Florida Seminoles, slightly less similar to other Indian groups, and still less to White and Negro populations. The Oklahoma sample of women showed a non-significantly greater fertility than those of Florida. Some indication of positive assortative mating for skin color was found in both groups.  相似文献   

14.
15.
Subtle differences in the pattern of arrangement of types of vertebrae and associated median skeletal structures between a benthic and limnetic species pair of threespine stickleback from Paxton Lake, British Columbia, are typical of those found throughout the range of the Gasterosteus aculeatus species complex. We established laboratory colonies from just three individuals of each species, and studied the effect of three generations of inbreeding on axial morphology. There was sufficient divergence in the location of individual elements between families to regenerate close to the entire range of axial diversity seen in threespine sticklebacks worldwide. Analysis of the patterns of variance and covariance between the axial locations of elements provides evidence for the action of both meristic and homeotic processes in the generation of morphological divergence within each species. Hybrid sticklebacks produced by the cross of limnetic and benthic parents tend to have intermediate morphologies, with dominance of either parental type evident for some elements. Effects of temperature and salinity were found to be small in direct comparison with between-family effects, and varied according to genetic background. These results demonstrate that considerable genetic variation for axial morphology is maintained in natural populations of threespine stickleback, and that differences between populations may be brought about rapidly by changes in frequency of alleles that have coordinated effects along the body axis.  相似文献   

16.
Variation in the frequency of individuals of Xanthisma texanum with B chromosomes among populations at the local level and variation in the frequency and distribution through time of individuals with B chromosomes within populations was investigated in a small area of southwestern Oklahoma and adjacent Texas between 1974 and 1987. The chromosome numbers of 1,224 individuals were determined from meiotic material; 15.8% of these had B chromosomes, less than 1% had three or four B chromosomes; none had more than four B chromosomes. The frequency of plants with B chromosomes among all sites sampled ranged from 0 to 33% and from 0 to 25% in sites separated by only a hundred meters; large differences in sample size occurred. Even at the subsite level large differences in frequencies in plants with B chromosomes were found. Within single sites, B chromosome frequency was not constant through time: the pattern of change differed among subsites within populations. In some cases the frequency went to zero. No correlations between environmental parameters and B chromosome frequency were documented.  相似文献   

17.
This study investigates prehension in 20 tufted capuchins (Cebus apella) in a reaching task requiring individuals to grasp a small food item fixed to a tray. The aim was twofold: 1) to describe capuchins' grasping techniques in detail, focusing on digit movements and on different areas of contact between the grasping fingers; and 2) to assess the relationship between grip types and manual laterality in this species. Capuchins picked up small food items using a wide variety of grips. In particular, 16 precision grip variants and 4 power grip variants were identified. The most frequently used precision grip involved the distal lateral areas of the thumb and the index finger, while the most preferred kind of power grip involved the thumb and the palm, with the thumb being enclosed by the other fingers. Immature capuchins picked up small food items using power grips more often than precision grips, while adult individuals exhibited no significant preference for either grip type. The analysis performed on the time capuchins took to grasp the food and withdraw it from the tray hole revealed that 1) precision grips were as efficient as power grips; 2) for precision grips, the left hand was faster than the right hand; and 3) for power grips, both hands were equally quick. Hand preference analysis, based on the frequency for the use of either hand for grasping actions, revealed no significant hand bias at group level. Likewise, there was no significant relationship between grip type and hand preference.  相似文献   

18.
Digital patterns of a sample on twins were analyzed to estimate the resemblance between monozygotic (MZ) and dizygotic (DZ) twins and to evaluate the mode of inheritance by the use of maximum likelihood based variance decomposition analysis. MZ twin resemblance of finger pattern types appears to be more pronounced than in DZ twins, which suggests the presence of genetic factors in the forming of fingertip patterns. The most parsimonious model shows twin resemblance in count of all three basic finger patterns on 10 fingers. It has significant dominant genetic variance component across all fingers. In the general model, the dominant genetic variance component proportion is similar for all fingertips (about 60%) and the sibling environmental variance is significantly nonzero, but the proportion between additive and dominant variance components was different. Application of genetic model fitting technique of segregation analyses clearly shows mode of inheritance. A dominant genetic variance component or a specific genetic system modifies the phenotypic expression of the fingertip patterns. The present study provided evidence of strong genetic component in finger pattern types and seems more informative compared to the earlier traditional method of correlation analysis.  相似文献   

19.
It remains unclear whether the frequency of marital coitus does in fact decline universally across the life course, what shape that decay normally takes, and what best accounts for it: increasing marriage duration, women's age or age of their partners. Using cross-sectional Demographic and Health Survey (DHS) data of 91,744 non-abstaining women in their first marriage, a generalized linear model is used to determine if there is a consistent pattern in the life course pattern of degradation in the frequency of marital coitus. Datasets were drawn from nineteen countries in Asia, Africa and the Americas. Use of very large samples allows proper disentangling of the effects of women's age, husband's age and marital duration, and use of samples from multiple countries allows consideration of the influence of varied prevailing fertility regimes and fertility-related practices on life course trajectories. It is found that declining coital frequency over time seems a shared demographic feature of human populations, but whether marriage duration, wife's age or husband's age is most responsible for that decline varies by country. In many cases, coital frequency actually increases with women's age into their thirties, once husband's age and marriage duration are taken into account, but in most cases coital frequency declines with husband's age and marital duration.  相似文献   

20.
Pubic hair was studied in 520 men and 270 women belonging to the various parts of the Northern Nigeria. An attempt has been made to study the pubic hair pattern in three age groups. The distribution of pubic hair was classified into four types, designated as horizontal, sagittal, acuminate and disperse. The acuminate or "masculine" type is present in approximately half of the men and 10 percent of the women. It is characteristic of 39.8 per cent of 19-20 years old males, and persists in 20.2 per cent of adult males. In the majority the division into "masculine" and "feminine" types is found to be satisfactory. There is definite relationship between the age of an individual and hair pattern. In males the decrease in frequency of the horizontal pattern with age is associated with increase in general hirsutism and is associated by the development of a disperse pubic hair pattern.  相似文献   

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