Materials.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Parent races true-breeding.. . . . . . . . . . . . . . . . . . . . . . . . . . . Crosses of Gold and Red. . . . . . . . . . . . . . . . . . . . . . . . . . . . . The exceptional female.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Nondisjunction. . . . . . . . . . . . . . . . . . . . . . ...

Poinsettia is an economically important ornamental potted plant in which certain bract colour variants are often obtained by mutation breeding. Previously, poinsettia, we identified Bract1, a GST gene involved the sequestration and transport of anthocyanins to vacuole. This carries short, highly mutable 4-bp repeat its coding region. Loss one unit leads loss function for homozygous mutants, ant...

The effects of the various evolutionary factors-mutation, cross breeding,. selection and inbreeding-can be reduced to common terms by considering the rates of change which they tend to bring about in the relative frequencies of alleles.' In the absence of such factors, there is constancy of gene frequencies from the symmetry of the Mendelian mechanism. The frequency (q) of a given gene changes ...

An understanding of the forces that contribute to the phylogenetically widespread phenomenon of sexual reproduction has posed a longstanding problem in evolutionary biology. Mutational theories contend that sex can be maintained when the deleterious mutation rate is sufficiently high, although empirical evidence is equivocal and experimental studies are rare. To test the influence of mutation o...

Pituitary dwarfism, associated with growth hormone (GH) deficiency, is an autosomal, recessively inherited disorder in shepherd dogs. As outlined in reference [49], pituitary dwarfism is a serious illness and clinical signs are not limited to physical appearance. Instead, the dwarfs suffer from a whole range of clinical manifestations. Without proper treatment, the long-term prognosis is poor. ...