D. J. Nolte
Articles written in Journal of Genetics
Volume 50 Issue 1 June 1950 pp 79-99
Volume 51 Issue 1 July 1952 pp 130-141
Volume 51 Issue 1 July 1952 pp 142-186
This investigation was mainly directed at the solution of the problem of the multiplicity of eye-colour genes in
For the purposes of routine quantitative comparison of the red and brown eye pigments of different mutant strains with those of the wild-type, methods are described for the rearing of normal-sized flies and for the extraction of the two pigments and their spectrophotometric analysis. The light-absorption curves are given of these pigments in the wild-type and various mutants, singly and in combination. The two pigments typical of the wild-type are found in all mutants with the exception of the alleles of the white locus which condition the production of a qualitatively changed red pigment.
Quantitative estimations of the pigments in the wild-type and the different mutants studied indicate the following effects of mutant genes:
A scheme is presented to show some of the interrelationships which exist between the various genes which affect eye pigmentation. The probable mode of action of the normal allele of white is at the level where a common substrate is differentiated for the formation of specific substrates for the red and brown chromogens, but where also certain by-products are formed for utilization in the protein carrier and granule system. The normal alleles of scarlet and brown then fit into the scheme at a later level, i.e. that of chromophore or chromoprotein formation. The action of the normal allele of raspberry2 seems to be at the level of cellular differentiation. In connexion with the mode of action of the normal alleles of the genes for ruby, carmine, garnet3 and carnation the concept is developed that many eye-colour genes affect eye pigmentation only indirectly, i.e. eye colour is influenced by them epigenetically, consequent on their main function being the directing of enzyme specificities for the breakdown and resynthesis of proteins during metamorphosis; the products of breakdown are utilized in the eye-pigmentary system which in this activity is partly an excretory system.
Volume 52 Issue 1 January 1954 pp 111-126
The large number of eye-colour mutants of
Histologically the eyes of these mutants are very similar excepting that in
The validity of the method of differential double extraction of the red and brown pigments is examined.
Evidence, based on the spectrophotometric curves of the extracts, is advanced for the affinities of the red and brown pigments, a common step in their chromophore formation being postulated during the stage of development of a precursor, or constituent, for combination with their specific chromogens.
An analysis of the light-absorption curves of pupal and imaginal eye extracts gives some indication of the course of development of the red and brown chromophores.
The five mutants produce mainly red pigment, although in the case of
To the known functions of the normal alleles of
Volume 52 Issue 1 January 1954 pp 127-139
The second and third groups of eye-colour mutants of
In all the mutants, excepting two, the normal types of red and brown pigments occur. In
An attempt is made to indicate the possible modes of action of these genes in eye pigmentation. It is postulated that the normal alleles of
Volume 53 Issue 1 January 1955 pp 1-10
The fourth and fifth groups of eye-colour mutants of
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