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401.
From approximately 1000 papers with data on protein polymorphism in some 216 breeds of cattle, 10 polymorphic proteins were compared in means and variances of gene frequencies (arcsin p½) for ten well-recognized breed groups for 196 of the breeds. The polymorphic proteins were α-lactalbumin, β-lactoglobulin, caseins (αsl, β and x), serum albumin, transferrin, haemoglobin, amylase I and carbonic anhydrase II. The breed groups were North European, Pied Lowland, European Red brachyceros, Channel Island brachyceros, Upland brachyceros, primigenius-brachyceros mixed, primigenius, Indian Zebu, African Humped (with Zebu admixture), and African Humped (Sanga).
The coherence within groups and the differences between groups are often impressive. Only carbonic anhydrase II fails to differentiate at least some of the major breed groups.
In some cases paradoxical distributions of rare genetic variants can be explained by a more detailed inspection of breed history.
The chemical data support the morphological and geographical divisions of cattle into major breed groups. There are three distinct but related brachyceros groups; for some polymorphisms the two Channel Island breeds, the Jersey and the Guernsey, are quite divergent. Although some authorities have considered the Pied Lowland as primigenius, it is a very distinct breed group.  相似文献   
402.
In a random coefficient repeated measures model, the regression coefficients relating the observations to some underlying variable, such as time, are themselves taken to be random distributed over experimental units. In this paper, a general approach to repeated measures analysis is extended to this wider model. In the model three specific error structures for the random regression coefficients have been studied, viz, the random coefficients variance matrix is considered to be (i) diagonal, (ii) proportional to the identity matrix and (iii) completely general. An example will be analyzed to illustrate the procedure.  相似文献   
403.
COMBO: a defined freshwater culture medium for algae and zooplankton   总被引:9,自引:0,他引:9  
In order to conduct experiments on interactions between animals and food organisms, it is necessary to develop a medium that adequately supports the growth of both algae and zooplankton without the need to alter the medium to accommodate either the algae or the animals. We devised a freshwater medium, named COMBO, that supports excellent growth of both algae and zooplankton. Two types of algae, Ankistrodesmus falcatus and Stephanodiscus hantzschii, were reared in COMBO and their growth rates were not significantly different from those of algae grown in a reference medium (WC). One of these algae, A. falcatus, was then fed to a cladoceran, Daphnia pulicaria, which was also cultured in COMBO, and the resulting fecundities of D. pulicaria were compared to those of animals reared in natural surface water. We also determined whether the value of COMBO as a medium for D. pulicaria was affected by modifications in nitrogen or phosphorus concentration to evaluate whether the new medium will be useful in nutritional research. Lowering the N or P content of COMBO did not affect the reproductive performance of D. pulicaria. Other researchers have also reported excellent growth and reproduction by numerous algae and zooplankton reared in COMBO. Our results suggest that COMBO is an effective artificial, defined culture medium capable of supporting robust growth and reproduction of both freshwater algae and zooplankton. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
404.
Ohne ZusammenfassungBesonderen Dank schuldet der Verfasser Herrn Dipl.-LandwirtIsenbeck für die Unterstützung bei der Übersetzung dieser Arbeit.  相似文献   
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A simple, of less than 20 min duration, quasi-isocratic high-pressure liquid chromatographic system designed for effective analysis of phenylthiohydantoin-amino acids derived from Edman sequencing is described. A second 30-min quasi-isocratic system is presented which may be used when sequenced samples contain extraneous 254 nm-absorbing material. Conditions affecting chromatogram reproducibility are also examined.  相似文献   
410.
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