Numerical taxonomic study of the graft chimaera + Laburno-cytisus adamii (Cytisus purpureus + Laburnum anagyroides)

A numerical taxonomic study of a graft chimaera is presented. This was made with the primary aim of elucidating the phonetic relationships between the chimaera and the two parents, but also illustrates some points concerning the weighting of characters and congruence between different sets of characters.
Branches were used as Operational Taxonomic Units, three of each of the biological kinds. The different branches of each kind were highly similar, with the chimaera being the most variable. Phonetically, the chimaera lay well offset from the line joining the parents, but otherwise about midway. Analyses made with characters determined mainly by one parent or the other showed that there is considerable interaction between the parental genotypes to yield the phenotype of the chimaera.
These relationships are much the same whether based on spatial or non-spatial quantitative characters, provided that the values are standardized; otherwise size and shape differences may be misleading. Qualitative characters can give rise to difficulties in such work, though they had little effect in the present example. The findings are discussed in relation to gene dominance.     

Statistical inference of the time-varying structure of gene-regulation networks

Background  

Biological networks are highly dynamic in response to environmental and physiological cues. This variability is in contrast to conventional analyses of biological networks, which have overwhelmingly employed static graph models which stay constant over time to describe biological systems and their underlying molecular interactions.     

A probability matrix for the identification of vibrios

A probability matrix for computer-assisted identification of vibrios has been constructed, based on the API 20E system. Data were gathered from 173 strains representing 31 taxa of vibrios and related organisms, from a variety of sources. The matrix was tested internally by four statistical programs. Program OVERMAT tested the separation and program MOSTTYP the discretion and homogeneity of the taxa. Most of the taxa were satisfactory but a few were less so; reasons for this are discussed. Program CHARSEP and program DIACHAR tested the separation and diagnostic values, respectively, of the characters used. The overall test error was 4–5%. The matrix was assessed externally by its performance in the identification of vibrio-like strains isolated from freshwater. Of 243 wild strains, 79–4% were identified with ten taxa, with a Willcox score of ζ 0–99.