Heterochromatin is both necessary for the expression of heterochromatic genes and
inhibitory for the expression of euchromatic genes. These two properties of heterochromatin …

Position‐effect variegation (PEV) was discovered in 1930 in a study of X‐ray‐induced
chromosomal rearrangements. Rearrangements that place euchromatic genes adjacent to a …

Monoclonal antibodies were prepared against a fraction of nuclear proteins of Drosophila
melanogaster identified as tightly binding to DNA. Four of these antibodies were directed …

A euchromatic gene placed in the vicinity of heterochromatin by a chromosomal
rearrangement generally exhibits position effect variegation (PEV), a clonally inherited …

Background The recent availability of genome sequences has provided unparalleled
insights into the broad-scale patterns of transposable element (TE) sequences in eukaryotic …

Messenger RNA transcribed in cultured Drosophila cells adapted for growth under
conditions permitting labeling to high specific activity has been analyzed by the technique of …

P-element transformants of a single rRNA gene (rDNA) were used to investigate the
relationship between the organization of the nucleolus organizer (NO) and rDNA function in …

Sex chromosomes originated from autosomes but have evolved a highly specialized
chromatin structure. Drosophila Y chromosomes are composed entirely of silent …

Interphase chromosome organization in four different Drosophila melanogaster tissues,
covering three to four levels of polyteny, has been analyzed. The results are based primarily …

Publisher Summary This chapter describes that the problems relating to the organization of
heterochromatin are prominent in the general thinking about the organization of genetic …