ISSN:
1573-4927
Keywords:
sepiapterin synthase
;
variegation
;
purple
;
Drosophila melanogaster
;
pteridine eye pigments
;
drosopterin
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Abstract A variegated position effect on the autonomous gene, purple, has been studied enzymologically in Drosophila melanogaster. Sepiapterin synthase, the enzyme system associated with pr +, was examined for activity in different developmental stages of the fly. The results indicate that T(Y:2) pr c5, cn/prc4 cn flies (flies in which pr + has been translocated and which exhibit variegation) have a reduced amount of enzyme activity as compared with both Oregon-R and pr 1 flies. This reduction in activity was not found in larval stages, which suggests that the inactivation process probably occurs in late larval or early pupal stages. The phenotype of the variegated adult has white eyes with red-colored spots and patches where drosopterins occur. The phenotype of the fly carrying the translocation is modified by the presence of additional Y chromosomes. This extends the observation from other systems that extra heterochromatin acts to suppress the variegated position effect. The advantages of studying the variegation by measuring enzyme activity, as well as the phenotypic expression, are several; for example, the developmental time at which variegation occurs may be estimated even though drosopterin synthesis is not occurring.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00484485
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