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Biomedical subjects

P Krishnan

Publications and source records attributed to P Krishnan.

43 records · Page 3Linked to original sources
PubMedDate not supplied

FISH mapping of the 5S and 18S-28S rDNA loci in different species of Glycine.

Wild germplasms are often the only significant sources of useful traits for crops, such as soybean, that have limited genetic variability. Before these germplasms can be effectively manipulated they must be characterized at the cytological and molecular levels. Modern soybean probably arose through an ancient allotetraploid event and subsequent diploidization of the genome. However, wild Glycine species have not been intensively investigated for this ancient polyploidy. In this article we determined the number of both the 5S and 18S-28S rDNA sequences in various members of the genus Glycine using FISH. Our results distinctly establish the loss of a 5S rDNA locus from the "diploid" (2n = 40) species and the loss of two from the (2n = 80) polyploids of GLYCINE: A similar diploidization of the 18S-28S rDNA gene family has occurred in G. canescens, G. clandestina, G. soja, and G. max (L.) Merr. (2n = 40). Although of different genome types, G. tabacina and G. tomentella (2n = 80) both showed two major 18S-28S rDNA loci per haploid genome, in contrast to the four loci that would be expected in chromosomes that have undergone two doubling events in their evolutionary history. It is evident that the evolution of the subgenus Glycine is more complex than that represented in a simple diploid-doubled to tetraploid model.

Chromosomes↗
PubMedDate not supplied

A typology of migration in Canada based on migrants' characteristics.

"Data from the 1981 Census of Canada are used to develop a typology of migrants on the basis of their personal characteristics. Migrants are defined as those individuals who have changed their residence since the 1976 Census, crossing at least a municipal boundary. Socio-economic and demographic characteristics are perceived to differentiate stayers from movers, and to distinguish each migrant type [that is to say] intraprovincial, interprovincial and international. Discriminant analysis is applied to classify people into migrant types based on their personal characteristics and the typology developed."

Americas↗
PubMedDate not supplied

On a method of robust standardization.

"The need of summary measures of the incidence of a phenomenon independent of age structure (composition) and other compositional factors is noted in demographic literature. One such index is developed in this paper. A standardized index is defined as robust, if it is least sensitive [to] the age structure of the standard population. The Banerjee-Stuvel price index is shown to have this property by a computer simulation experiment."

Age Distribution↗
PubMedDate not supplied

Medical education.

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Asia↗